Search Results

Search found 50550 results on 2022 pages for 'method resolution order'.

Page 250/2022 | < Previous Page | 246 247 248 249 250 251 252 253 254 255 256 257  | Next Page >

  • C#/.NET Little Wonders: The Concurrent Collections (1 of 3)

    - by James Michael Hare
    Once again we consider some of the lesser known classes and keywords of C#.  In the next few weeks, we will discuss the concurrent collections and how they have changed the face of concurrent programming. This week’s post will begin with a general introduction and discuss the ConcurrentStack<T> and ConcurrentQueue<T>.  Then in the following post we’ll discuss the ConcurrentDictionary<T> and ConcurrentBag<T>.  Finally, we shall close on the third post with a discussion of the BlockingCollection<T>. For more of the "Little Wonders" posts, see the index here. A brief history of collections In the beginning was the .NET 1.0 Framework.  And out of this framework emerged the System.Collections namespace, and it was good.  It contained all the basic things a growing programming language needs like the ArrayList and Hashtable collections.  The main problem, of course, with these original collections is that they held items of type object which means you had to be disciplined enough to use them correctly or you could end up with runtime errors if you got an object of a type you weren't expecting. Then came .NET 2.0 and generics and our world changed forever!  With generics the C# language finally got an equivalent of the very powerful C++ templates.  As such, the System.Collections.Generic was born and we got type-safe versions of all are favorite collections.  The List<T> succeeded the ArrayList and the Dictionary<TKey,TValue> succeeded the Hashtable and so on.  The new versions of the library were not only safer because they checked types at compile-time, in many cases they were more performant as well.  So much so that it's Microsoft's recommendation that the System.Collections original collections only be used for backwards compatibility. So we as developers came to know and love the generic collections and took them into our hearts and embraced them.  The problem is, thread safety in both the original collections and the generic collections can be problematic, for very different reasons. Now, if you are only doing single-threaded development you may not care – after all, no locking is required.  Even if you do have multiple threads, if a collection is “load-once, read-many” you don’t need to do anything to protect that container from multi-threaded access, as illustrated below: 1: public static class OrderTypeTranslator 2: { 3: // because this dictionary is loaded once before it is ever accessed, we don't need to synchronize 4: // multi-threaded read access 5: private static readonly Dictionary<string, char> _translator = new Dictionary<string, char> 6: { 7: {"New", 'N'}, 8: {"Update", 'U'}, 9: {"Cancel", 'X'} 10: }; 11:  12: // the only public interface into the dictionary is for reading, so inherently thread-safe 13: public static char? Translate(string orderType) 14: { 15: char charValue; 16: if (_translator.TryGetValue(orderType, out charValue)) 17: { 18: return charValue; 19: } 20:  21: return null; 22: } 23: } Unfortunately, most of our computer science problems cannot get by with just single-threaded applications or with multi-threading in a load-once manner.  Looking at  today's trends, it's clear to see that computers are not so much getting faster because of faster processor speeds -- we've nearly reached the limits we can push through with today's technologies -- but more because we're adding more cores to the boxes.  With this new hardware paradigm, it is even more important to use multi-threaded applications to take full advantage of parallel processing to achieve higher application speeds. So let's look at how to use collections in a thread-safe manner. Using historical collections in a concurrent fashion The early .NET collections (System.Collections) had a Synchronized() static method that could be used to wrap the early collections to make them completely thread-safe.  This paradigm was dropped in the generic collections (System.Collections.Generic) because having a synchronized wrapper resulted in atomic locks for all operations, which could prove overkill in many multithreading situations.  Thus the paradigm shifted to having the user of the collection specify their own locking, usually with an external object: 1: public class OrderAggregator 2: { 3: private static readonly Dictionary<string, List<Order>> _orders = new Dictionary<string, List<Order>>(); 4: private static readonly _orderLock = new object(); 5:  6: public void Add(string accountNumber, Order newOrder) 7: { 8: List<Order> ordersForAccount; 9:  10: // a complex operation like this should all be protected 11: lock (_orderLock) 12: { 13: if (!_orders.TryGetValue(accountNumber, out ordersForAccount)) 14: { 15: _orders.Add(accountNumber, ordersForAccount = new List<Order>()); 16: } 17:  18: ordersForAccount.Add(newOrder); 19: } 20: } 21: } Notice how we’re performing several operations on the dictionary under one lock.  With the Synchronized() static methods of the early collections, you wouldn’t be able to specify this level of locking (a more macro-level).  So in the generic collections, it was decided that if a user needed synchronization, they could implement their own locking scheme instead so that they could provide synchronization as needed. The need for better concurrent access to collections Here’s the problem: it’s relatively easy to write a collection that locks itself down completely for access, but anything more complex than that can be difficult and error-prone to write, and much less to make it perform efficiently!  For example, what if you have a Dictionary that has frequent reads but in-frequent updates?  Do you want to lock down the entire Dictionary for every access?  This would be overkill and would prevent concurrent reads.  In such cases you could use something like a ReaderWriterLockSlim which allows for multiple readers in a lock, and then once a writer grabs the lock it blocks all further readers until the writer is done (in a nutshell).  This is all very complex stuff to consider. Fortunately, this is where the Concurrent Collections come in.  The Parallel Computing Platform team at Microsoft went through great pains to determine how to make a set of concurrent collections that would have the best performance characteristics for general case multi-threaded use. Now, as in all things involving threading, you should always make sure you evaluate all your container options based on the particular usage scenario and the degree of parallelism you wish to acheive. This article should not be taken to understand that these collections are always supperior to the generic collections. Each fills a particular need for a particular situation. Understanding what each container is optimized for is key to the success of your application whether it be single-threaded or multi-threaded. General points to consider with the concurrent collections The MSDN points out that the concurrent collections all support the ICollection interface. However, since the collections are already synchronized, the IsSynchronized property always returns false, and SyncRoot always returns null.  Thus you should not attempt to use these properties for synchronization purposes. Note that since the concurrent collections also may have different operations than the traditional data structures you may be used to.  Now you may ask why they did this, but it was done out of necessity to keep operations safe and atomic.  For example, in order to do a Pop() on a stack you have to know the stack is non-empty, but between the time you check the stack’s IsEmpty property and then do the Pop() another thread may have come in and made the stack empty!  This is why some of the traditional operations have been changed to make them safe for concurrent use. In addition, some properties and methods in the concurrent collections achieve concurrency by creating a snapshot of the collection, which means that some operations that were traditionally O(1) may now be O(n) in the concurrent models.  I’ll try to point these out as we talk about each collection so you can be aware of any potential performance impacts.  Finally, all the concurrent containers are safe for enumeration even while being modified, but some of the containers support this in different ways (snapshot vs. dirty iteration).  Once again I’ll highlight how thread-safe enumeration works for each collection. ConcurrentStack<T>: The thread-safe LIFO container The ConcurrentStack<T> is the thread-safe counterpart to the System.Collections.Generic.Stack<T>, which as you may remember is your standard last-in-first-out container.  If you think of algorithms that favor stack usage (for example, depth-first searches of graphs and trees) then you can see how using a thread-safe stack would be of benefit. The ConcurrentStack<T> achieves thread-safe access by using System.Threading.Interlocked operations.  This means that the multi-threaded access to the stack requires no traditional locking and is very, very fast! For the most part, the ConcurrentStack<T> behaves like it’s Stack<T> counterpart with a few differences: Pop() was removed in favor of TryPop() Returns true if an item existed and was popped and false if empty. PushRange() and TryPopRange() were added Allows you to push multiple items and pop multiple items atomically. Count takes a snapshot of the stack and then counts the items. This means it is a O(n) operation, if you just want to check for an empty stack, call IsEmpty instead which is O(1). ToArray() and GetEnumerator() both also take snapshots. This means that iteration over a stack will give you a static view at the time of the call and will not reflect updates. Pushing on a ConcurrentStack<T> works just like you’d expect except for the aforementioned PushRange() method that was added to allow you to push a range of items concurrently. 1: var stack = new ConcurrentStack<string>(); 2:  3: // adding to stack is much the same as before 4: stack.Push("First"); 5:  6: // but you can also push multiple items in one atomic operation (no interleaves) 7: stack.PushRange(new [] { "Second", "Third", "Fourth" }); For looking at the top item of the stack (without removing it) the Peek() method has been removed in favor of a TryPeek().  This is because in order to do a peek the stack must be non-empty, but between the time you check for empty and the time you execute the peek the stack contents may have changed.  Thus the TryPeek() was created to be an atomic check for empty, and then peek if not empty: 1: // to look at top item of stack without removing it, can use TryPeek. 2: // Note that there is no Peek(), this is because you need to check for empty first. TryPeek does. 3: string item; 4: if (stack.TryPeek(out item)) 5: { 6: Console.WriteLine("Top item was " + item); 7: } 8: else 9: { 10: Console.WriteLine("Stack was empty."); 11: } Finally, to remove items from the stack, we have the TryPop() for single, and TryPopRange() for multiple items.  Just like the TryPeek(), these operations replace Pop() since we need to ensure atomically that the stack is non-empty before we pop from it: 1: // to remove items, use TryPop or TryPopRange to get multiple items atomically (no interleaves) 2: if (stack.TryPop(out item)) 3: { 4: Console.WriteLine("Popped " + item); 5: } 6:  7: // TryPopRange will only pop up to the number of spaces in the array, the actual number popped is returned. 8: var poppedItems = new string[2]; 9: int numPopped = stack.TryPopRange(poppedItems); 10:  11: foreach (var theItem in poppedItems.Take(numPopped)) 12: { 13: Console.WriteLine("Popped " + theItem); 14: } Finally, note that as stated before, GetEnumerator() and ToArray() gets a snapshot of the data at the time of the call.  That means if you are enumerating the stack you will get a snapshot of the stack at the time of the call.  This is illustrated below: 1: var stack = new ConcurrentStack<string>(); 2:  3: // adding to stack is much the same as before 4: stack.Push("First"); 5:  6: var results = stack.GetEnumerator(); 7:  8: // but you can also push multiple items in one atomic operation (no interleaves) 9: stack.PushRange(new [] { "Second", "Third", "Fourth" }); 10:  11: while(results.MoveNext()) 12: { 13: Console.WriteLine("Stack only has: " + results.Current); 14: } The only item that will be printed out in the above code is "First" because the snapshot was taken before the other items were added. This may sound like an issue, but it’s really for safety and is more correct.  You don’t want to enumerate a stack and have half a view of the stack before an update and half a view of the stack after an update, after all.  In addition, note that this is still thread-safe, whereas iterating through a non-concurrent collection while updating it in the old collections would cause an exception. ConcurrentQueue<T>: The thread-safe FIFO container The ConcurrentQueue<T> is the thread-safe counterpart of the System.Collections.Generic.Queue<T> class.  The concurrent queue uses an underlying list of small arrays and lock-free System.Threading.Interlocked operations on the head and tail arrays.  Once again, this allows us to do thread-safe operations without the need for heavy locks! The ConcurrentQueue<T> (like the ConcurrentStack<T>) has some departures from the non-concurrent counterpart.  Most notably: Dequeue() was removed in favor of TryDequeue(). Returns true if an item existed and was dequeued and false if empty. Count does not take a snapshot It subtracts the head and tail index to get the count.  This results overall in a O(1) complexity which is quite good.  It’s still recommended, however, that for empty checks you call IsEmpty instead of comparing Count to zero. ToArray() and GetEnumerator() both take snapshots. This means that iteration over a queue will give you a static view at the time of the call and will not reflect updates. The Enqueue() method on the ConcurrentQueue<T> works much the same as the generic Queue<T>: 1: var queue = new ConcurrentQueue<string>(); 2:  3: // adding to queue is much the same as before 4: queue.Enqueue("First"); 5: queue.Enqueue("Second"); 6: queue.Enqueue("Third"); For front item access, the TryPeek() method must be used to attempt to see the first item if the queue.  There is no Peek() method since, as you’ll remember, we can only peek on a non-empty queue, so we must have an atomic TryPeek() that checks for empty and then returns the first item if the queue is non-empty. 1: // to look at first item in queue without removing it, can use TryPeek. 2: // Note that there is no Peek(), this is because you need to check for empty first. TryPeek does. 3: string item; 4: if (queue.TryPeek(out item)) 5: { 6: Console.WriteLine("First item was " + item); 7: } 8: else 9: { 10: Console.WriteLine("Queue was empty."); 11: } Then, to remove items you use TryDequeue().  Once again this is for the same reason we have TryPeek() and not Peek(): 1: // to remove items, use TryDequeue. If queue is empty returns false. 2: if (queue.TryDequeue(out item)) 3: { 4: Console.WriteLine("Dequeued first item " + item); 5: } Just like the concurrent stack, the ConcurrentQueue<T> takes a snapshot when you call ToArray() or GetEnumerator() which means that subsequent updates to the queue will not be seen when you iterate over the results.  Thus once again the code below will only show the first item, since the other items were added after the snapshot. 1: var queue = new ConcurrentQueue<string>(); 2:  3: // adding to queue is much the same as before 4: queue.Enqueue("First"); 5:  6: var iterator = queue.GetEnumerator(); 7:  8: queue.Enqueue("Second"); 9: queue.Enqueue("Third"); 10:  11: // only shows First 12: while (iterator.MoveNext()) 13: { 14: Console.WriteLine("Dequeued item " + iterator.Current); 15: } Using collections concurrently You’ll notice in the examples above I stuck to using single-threaded examples so as to make them deterministic and the results obvious.  Of course, if we used these collections in a truly multi-threaded way the results would be less deterministic, but would still be thread-safe and with no locking on your part required! For example, say you have an order processor that takes an IEnumerable<Order> and handles each other in a multi-threaded fashion, then groups the responses together in a concurrent collection for aggregation.  This can be done easily with the TPL’s Parallel.ForEach(): 1: public static IEnumerable<OrderResult> ProcessOrders(IEnumerable<Order> orderList) 2: { 3: var proxy = new OrderProxy(); 4: var results = new ConcurrentQueue<OrderResult>(); 5:  6: // notice that we can process all these in parallel and put the results 7: // into our concurrent collection without needing any external locking! 8: Parallel.ForEach(orderList, 9: order => 10: { 11: var result = proxy.PlaceOrder(order); 12:  13: results.Enqueue(result); 14: }); 15:  16: return results; 17: } Summary Obviously, if you do not need multi-threaded safety, you don’t need to use these collections, but when you do need multi-threaded collections these are just the ticket! The plethora of features (I always think of the movie The Three Amigos when I say plethora) built into these containers and the amazing way they acheive thread-safe access in an efficient manner is wonderful to behold. Stay tuned next week where we’ll continue our discussion with the ConcurrentBag<T> and the ConcurrentDictionary<TKey,TValue>. For some excellent information on the performance of the concurrent collections and how they perform compared to a traditional brute-force locking strategy, see this wonderful whitepaper by the Microsoft Parallel Computing Platform team here.   Tweet Technorati Tags: C#,.NET,Concurrent Collections,Collections,Multi-Threading,Little Wonders,BlackRabbitCoder,James Michael Hare

    Read the article

  • SQL SERVER – Find Most Expensive Queries Using DMV

    - by pinaldave
    The title of this post is what I can express here for this quick blog post. I was asked in recent query tuning consultation project, if I can share my script which I use to figure out which is the most expensive queries are running on SQL Server. This script is very basic and very simple, there are many different versions are available online. This basic script does do the job which I expect to do – find out the most expensive queries on SQL Server Box. SELECT TOP 10 SUBSTRING(qt.TEXT, (qs.statement_start_offset/2)+1, ((CASE qs.statement_end_offset WHEN -1 THEN DATALENGTH(qt.TEXT) ELSE qs.statement_end_offset END - qs.statement_start_offset)/2)+1), qs.execution_count, qs.total_logical_reads, qs.last_logical_reads, qs.total_logical_writes, qs.last_logical_writes, qs.total_worker_time, qs.last_worker_time, qs.total_elapsed_time/1000000 total_elapsed_time_in_S, qs.last_elapsed_time/1000000 last_elapsed_time_in_S, qs.last_execution_time, qp.query_plan FROM sys.dm_exec_query_stats qs CROSS APPLY sys.dm_exec_sql_text(qs.sql_handle) qt CROSS APPLY sys.dm_exec_query_plan(qs.plan_handle) qp ORDER BY qs.total_logical_reads DESC -- logical reads -- ORDER BY qs.total_logical_writes DESC -- logical writes -- ORDER BY qs.total_worker_time DESC -- CPU time You can change the ORDER BY clause to order this table with different parameters. I invite my reader to share their scripts. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, SQL, SQL Authority, SQL Optimization, SQL Performance, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, SQLAuthority News, SQLServer, T SQL, Technology Tagged: SQL DMV

    Read the article

  • AuthnRequest Settings in OIF / SP

    - by Damien Carru
    In this article, I will list the various OIF/SP settings that affect how an AuthnRequest message is created in OIF in a Federation SSO flow. The AuthnRequest message is used by an SP to start a Federation SSO operation and to indicate to the IdP how the operation should be executed: How the user should be challenged at the IdP Whether or not the user should be challenged at the IdP, even if a session already exists at the IdP for this user Which NameID format should be requested in the SAML Assertion Which binding (Artifact or HTTP-POST) should be requested from the IdP to send the Assertion Which profile should be used by OIF/SP to send the AuthnRequest message Enjoy the reading! Protocols The SAML 2.0, SAML 1.1 and OpenID 2.0 protocols define different message elements and rules that allow an administrator to influence the Federation SSO flows in different manners, when the SP triggers an SSO operation: SAML 2.0 allows extensive customization via the AuthnRequest message SAML 1.1 does not allow any customization, since the specifications do not define an authentication request message OpenID 2.0 allows for some customization, mainly via the OpenID 2.0 extensions such as PAPE or UI SAML 2.0 OIF/SP allows the customization of the SAML 2.0 AuthnRequest message for the following elements: ForceAuthn: Boolean indicating whether or not the IdP should force the user for re-authentication, even if the user has still a valid session By default set to false IsPassive Boolean indicating whether or not the IdP is allowed to interact with the user as part of the Federation SSO operation. If false, the Federation SSO operation might result in a failure with the NoPassive error code, because the IdP will not have been able to identify the user By default set to false RequestedAuthnContext Element indicating how the user should be challenged at the IdP If the SP requests a Federation Authentication Method unknown to the IdP or for which the IdP is not configured, then the Federation SSO flow will result in a failure with the NoAuthnContext error code By default missing NameIDPolicy Element indicating which NameID format the IdP should include in the SAML Assertion If the SP requests a NameID format unknown to the IdP or for which the IdP is not configured, then the Federation SSO flow will result in a failure with the InvalidNameIDPolicy error code If missing, the IdP will generally use the default NameID format configured for this SP partner at the IdP By default missing ProtocolBinding Element indicating which SAML binding should be used by the IdP to redirect the user to the SP with the SAML Assertion Set to Artifact or HTTP-POST By default set to HTTP-POST OIF/SP also allows the administrator to configure the server to: Set which binding should be used by OIF/SP to redirect the user to the IdP with the SAML 2.0 AuthnRequest message: Redirect or HTTP-POST By default set to Redirect Set which binding should be used by OIF/SP to redirect the user to the IdP during logout with SAML 2.0 Logout messages: Redirect or HTTP-POST By default set to Redirect SAML 1.1 The SAML 1.1 specifications do not define a message for the SP to send to the IdP when a Federation SSO operation is started. As such, there is no capability to configure OIF/SP on how to affect the start of the Federation SSO flow. OpenID 2.0 OpenID 2.0 defines several extensions that can be used by the SP/RP to affect how the Federation SSO operation will take place: OpenID request: mode: String indicating if the IdP/OP can visually interact with the user checkid_immediate does not allow the IdP/OP to interact with the user checkid_setup allows user interaction By default set to checkid_setup PAPE Extension: max_auth_age : Integer indicating in seconds the maximum amount of time since when the user authenticated at the IdP. If MaxAuthnAge is bigger that the time since when the user last authenticated at the IdP, then the user must be re-challenged. OIF/SP will set this attribute to 0 if the administrator configured ForceAuthn to true, otherwise this attribute won't be set Default missing preferred_auth_policies Contains a Federation Authentication Method Element indicating how the user should be challenged at the IdP By default missing Only specified in the OpenID request if the IdP/OP supports PAPE in XRDS, if OpenID discovery is used. UI Extension Popup mode Boolean indicating the popup mode is enabled for the Federation SSO By default missing Language Preference String containing the preferred language, set based on the browser's language preferences. By default missing Icon: Boolean indicating if the icon feature is enabled. In that case, the IdP/OP would look at the SP/RP XRDS to determine how to retrieve the icon By default missing Only specified in the OpenID request if the IdP/OP supports UI Extenstion in XRDS, if OpenID discovery is used. ForceAuthn and IsPassive WLST Command OIF/SP provides the WLST configureIdPAuthnRequest() command to set: ForceAuthn as a boolean: In a SAML 2.0 AuthnRequest, the ForceAuthn field will be set to true or false In an OpenID 2.0 request, if ForceAuthn in the configuration was set to true, then the max_auth_age field of the PAPE request will be set to 0, otherwise, max_auth_age won't be set IsPassive as a boolean: In a SAML 2.0 AuthnRequest, the IsPassive field will be set to true or false In an OpenID 2.0 request, if IsPassive in the configuration was set to true, then the mode field of the OpenID request will be set to checkid_immediate, otherwise set to checkid_setup Test In this test, OIF/SP is integrated with a remote SAML 2.0 IdP Partner, with the OOTB configuration. Based on this setup, when OIF/SP starts a Federation SSO flow, the following SAML 2.0 AuthnRequest would be generated: <samlp:AuthnRequest ProtocolBinding="urn:oasis:names:tc:SAML:2.0:bindings:HTTP-POST" ID="id-E4BOT7lwbYK56lO57dBaqGUFq01WJSjAHiSR60Q4" Version="2.0" IssueInstant="2014-04-01T21:39:14Z" Destination="https://acme.com/saml20/sso">   <saml:Issuer Format="urn:oasis:names:tc:SAML:2.0:nameid-format:entity">https://sp.com/oam/fed</saml:Issuer>   <samlp:NameIDPolicy AllowCreate="true"/></samlp:AuthnRequest> Let's configure OIF/SP for that IdP Partner, so that the SP will require the IdP to re-challenge the user, even if the user is already authenticated: Enter the WLST environment by executing:$IAM_ORACLE_HOME/common/bin/wlst.sh Connect to the WLS Admin server:connect() Navigate to the Domain Runtime branch:domainRuntime() Execute the configureIdPAuthnRequest() command:configureIdPAuthnRequest(partner="AcmeIdP", forceAuthn="true") Exit the WLST environment:exit() After the changes, the following SAML 2.0 AuthnRequest would be generated: <samlp:AuthnRequest ForceAuthn="true" ProtocolBinding="urn:oasis:names:tc:SAML:2.0:bindings:HTTP-POST" ID="id-E4BOT7lwbYK56lO57dBaqGUFq01WJSjAHiSR60Q4" Version="2.0" IssueInstant="2014-04-01T21:39:14Z" Destination="https://acme.com/saml20/sso">   <saml:Issuer Format="urn:oasis:names:tc:SAML:2.0:nameid-format:entity">https://sp.com/oam/fed</saml:Issuer>   <samlp:NameIDPolicy AllowCreate="true"/></samlp:AuthnRequest> To display or delete the ForceAuthn/IsPassive settings, perform the following operatons: Enter the WLST environment by executing:$IAM_ORACLE_HOME/common/bin/wlst.sh Connect to the WLS Admin server:connect() Navigate to the Domain Runtime branch:domainRuntime() Execute the configureIdPAuthnRequest() command: To display the ForceAuthn/IsPassive settings on the partnerconfigureIdPAuthnRequest(partner="AcmeIdP", displayOnly="true") To delete the ForceAuthn/IsPassive settings from the partnerconfigureIdPAuthnRequest(partner="AcmeIdP", delete="true") Exit the WLST environment:exit() Requested Fed Authn Method In my earlier "Fed Authentication Method Requests in OIF / SP" article, I discussed how OIF/SP could be configured to request a specific Federation Authentication Method from the IdP when starting a Federation SSO operation, by setting elements in the SSO request message. WLST Command The OIF WLST commands that can be used are: setIdPPartnerProfileRequestAuthnMethod() which will configure the requested Federation Authentication Method in a specific IdP Partner Profile, and accepts the following parameters: partnerProfile: name of the IdP Partner Profile authnMethod: the Federation Authentication Method to request displayOnly: an optional parameter indicating if the method should display the current requested Federation Authentication Method instead of setting it delete: an optional parameter indicating if the method should delete the current requested Federation Authentication Method instead of setting it setIdPPartnerRequestAuthnMethod() which will configure the specified IdP Partner entry with the requested Federation Authentication Method, and accepts the following parameters: partner: name of the IdP Partner authnMethod: the Federation Authentication Method to request displayOnly: an optional parameter indicating if the method should display the current requested Federation Authentication Method instead of setting it delete: an optional parameter indicating if the method should delete the current requested Federation Authentication Method instead of setting it This applies to SAML 2.0 and OpenID 2.0 protocols. See the "Fed Authentication Method Requests in OIF / SP" article for more information. Test In this test, OIF/SP is integrated with a remote SAML 2.0 IdP Partner, with the OOTB configuration. Based on this setup, when OIF/SP starts a Federation SSO flow, the following SAML 2.0 AuthnRequest would be generated: <samlp:AuthnRequest ProtocolBinding="urn:oasis:names:tc:SAML:2.0:bindings:HTTP-POST" ID="id-E4BOT7lwbYK56lO57dBaqGUFq01WJSjAHiSR60Q4" Version="2.0" IssueInstant="2014-04-01T21:39:14Z" Destination="https://acme.com/saml20/sso">   <saml:Issuer Format="urn:oasis:names:tc:SAML:2.0:nameid-format:entity">https://sp.com/oam/fed</saml:Issuer>   <samlp:NameIDPolicy AllowCreate="true"/></samlp:AuthnRequest> Let's configure OIF/SP for that IdP Partner, so that the SP will request the IdP to use a mechanism mapped to the urn:oasis:names:tc:SAML:2.0:ac:classes:X509 Federation Authentication Method to authenticate the user: Enter the WLST environment by executing:$IAM_ORACLE_HOME/common/bin/wlst.sh Connect to the WLS Admin server:connect() Navigate to the Domain Runtime branch:domainRuntime() Execute the setIdPPartnerRequestAuthnMethod() command:setIdPPartnerRequestAuthnMethod("AcmeIdP", "urn:oasis:names:tc:SAML:2.0:ac:classes:X509") Exit the WLST environment:exit() After the changes, the following SAML 2.0 AuthnRequest would be generated: <samlp:AuthnRequest ProtocolBinding="urn:oasis:names:tc:SAML:2.0:bindings:HTTP-POST" ID="id-E4BOT7lwbYK56lO57dBaqGUFq01WJSjAHiSR60Q4" Version="2.0" IssueInstant="2014-04-01T21:39:14Z" Destination="https://acme.com/saml20/sso">   <saml:Issuer Format="urn:oasis:names:tc:SAML:2.0:nameid-format:entity">https://sp.com/oam/fed</saml:Issuer>   <samlp:NameIDPolicy AllowCreate="true"/>   <samlp:RequestedAuthnContext Comparison="minimum">      <saml:AuthnContextClassRef xmlns:saml="urn:oasis:names:tc:SAML:2.0:assertion">         urn:oasis:names:tc:SAML:2.0:ac:classes:X509      </saml:AuthnContextClassRef>   </samlp:RequestedAuthnContext></samlp:AuthnRequest> NameID Format The SAML 2.0 protocol allows for the SP to request from the IdP a specific NameID format to be used when the Assertion is issued by the IdP. Note: SAML 1.1 and OpenID 2.0 do not provide such a mechanism Configuring OIF The administrator can configure OIF/SP to request a NameID format in the SAML 2.0 AuthnRequest via: The OAM Administration Console, in the IdP Partner entry The OIF WLST setIdPPartnerNameIDFormat() command that will modify the IdP Partner configuration OAM Administration Console To configure the requested NameID format via the OAM Administration Console, perform the following steps: Go to the OAM Administration Console: http(s)://oam-admin-host:oam-admin-port/oamconsole Navigate to Identity Federation -> Service Provider Administration Open the IdP Partner you wish to modify In the Authentication Request NameID Format dropdown box with one of the values None The NameID format will be set Default Email Address The NameID format will be set urn:oasis:names:tc:SAML:1.1:nameid-format:emailAddress X.509 Subject The NameID format will be set urn:oasis:names:tc:SAML:1.1:nameid-format:X509SubjectName Windows Name Qualifier The NameID format will be set urn:oasis:names:tc:SAML:1.1:nameid-format:WindowsDomainQualifiedName Kerberos The NameID format will be set urn:oasis:names:tc:SAML:2.0:nameid-format:kerberos Transient The NameID format will be set urn:oasis:names:tc:SAML:2.0:nameid-format:transient Unspecified The NameID format will be set urn:oasis:names:tc:SAML:1.1:nameid-format:unspecified Custom In this case, a field would appear allowing the administrator to indicate the custom NameID format to use The NameID format will be set to the specified format Persistent The NameID format will be set urn:oasis:names:tc:SAML:2.0:nameid-format:persistent I selected Email Address in this example Save WLST Command To configure the requested NameID format via the OIF WLST setIdPPartnerNameIDFormat() command, perform the following steps: Enter the WLST environment by executing:$IAM_ORACLE_HOME/common/bin/wlst.sh Connect to the WLS Admin server:connect() Navigate to the Domain Runtime branch:domainRuntime() Execute the setIdPPartnerNameIDFormat() command:setIdPPartnerNameIDFormat("PARTNER", "FORMAT", customFormat="CUSTOM") Replace PARTNER with the IdP Partner name Replace FORMAT with one of the following: orafed-none The NameID format will be set Default orafed-emailaddress The NameID format will be set urn:oasis:names:tc:SAML:1.1:nameid-format:emailAddress orafed-x509 The NameID format will be set urn:oasis:names:tc:SAML:1.1:nameid-format:X509SubjectName orafed-windowsnamequalifier The NameID format will be set urn:oasis:names:tc:SAML:1.1:nameid-format:WindowsDomainQualifiedName orafed-kerberos The NameID format will be set urn:oasis:names:tc:SAML:2.0:nameid-format:kerberos orafed-transient The NameID format will be set urn:oasis:names:tc:SAML:2.0:nameid-format:transient orafed-unspecified The NameID format will be set urn:oasis:names:tc:SAML:1.1:nameid-format:unspecified orafed-custom In this case, a field would appear allowing the administrator to indicate the custom NameID format to use The NameID format will be set to the specified format orafed-persistent The NameID format will be set urn:oasis:names:tc:SAML:2.0:nameid-format:persistent customFormat will need to be set if the FORMAT is set to orafed-custom An example would be:setIdPPartnerNameIDFormat("AcmeIdP", "orafed-emailaddress") Exit the WLST environment:exit() Test In this test, OIF/SP is integrated with a remote SAML 2.0 IdP Partner, with the OOTB configuration. Based on this setup, when OIF/SP starts a Federation SSO flow, the following SAML 2.0 AuthnRequest would be generated: <samlp:AuthnRequest ProtocolBinding="urn:oasis:names:tc:SAML:2.0:bindings:HTTP-POST" ID="id-E4BOT7lwbYK56lO57dBaqGUFq01WJSjAHiSR60Q4" Version="2.0" IssueInstant="2014-04-01T21:39:14Z" Destination="https://acme.com/saml20/sso">   <saml:Issuer Format="urn:oasis:names:tc:SAML:2.0:nameid-format:entity">https://sp.com/oam/fed</saml:Issuer> <samlp:NameIDPolicy AllowCreate="true"/></samlp:AuthnRequest> After the changes performed either via the OAM Administration Console or via the OIF WLST setIdPPartnerNameIDFormat() command where Email Address would be requested as the NameID Format, the following SAML 2.0 AuthnRequest would be generated: <samlp:AuthnRequest ForceAuthn="false" IsPassive="false" ProtocolBinding="urn:oasis:names:tc:SAML:2.0:bindings:HTTP-POST" ID="id-E4BOT7lwbYK56lO57dBaqGUFq01WJSjAHiSR60Q4" Version="2.0" IssueInstant="2014-04-01T21:39:14Z" Destination="https://acme.com/saml20/sso">   <saml:Issuer Format="urn:oasis:names:tc:SAML:2.0:nameid-format:entity">https://sp.com/oam/fed</saml:Issuer> <samlp:NameIDPolicy Format="urn:oasis:names:tc:SAML:1.1:nameid-format:emailAddress" AllowCreate="true"/></samlp:AuthnRequest> Protocol Binding The SAML 2.0 specifications define a way for the SP to request which binding should be used by the IdP to redirect the user to the SP with the SAML 2.0 Assertion: the ProtocolBinding attribute indicates the binding the IdP should use. It is set to: Either urn:oasis:names:tc:SAML:2.0:bindings:HTTP-POST for HTTP-POST Or urn:oasis:names:tc:SAML:2.0:bindings:Artifact for Artifact The SAML 2.0 specifications also define different ways to redirect the user from the SP to the IdP with the SAML 2.0 AuthnRequest message, as the SP can send the message: Either via HTTP Redirect Or HTTP POST (Other bindings can theoretically be used such as Artifact, but these are not used in practice) Configuring OIF OIF can be configured: Via the OAM Administration Console or the OIF WLST configureSAMLBinding() command to set the Assertion Response binding to be used Via the OIF WLST configureSAMLBinding() command to indicate how the SAML AuthnRequest message should be sent Note: the binding for sending the SAML 2.0 AuthnRequest message will also be used to send the SAML 2.0 LogoutRequest and LogoutResponse messages. OAM Administration Console To configure the SSO Response/Assertion Binding via the OAM Administration Console, perform the following steps: Go to the OAM Administration Console: http(s)://oam-admin-host:oam-admin-port/oamconsole Navigate to Identity Federation -> Service Provider Administration Open the IdP Partner you wish to modify Check the "HTTP POST SSO Response Binding" box to request the IdP to return the SSO Response via HTTP POST, otherwise uncheck it to request artifact Save WLST Command To configure the SSO Response/Assertion Binding as well as the AuthnRequest Binding via the OIF WLST configureSAMLBinding() command, perform the following steps: Enter the WLST environment by executing:$IAM_ORACLE_HOME/common/bin/wlst.sh Connect to the WLS Admin server:connect() Navigate to the Domain Runtime branch:domainRuntime() Execute the configureSAMLBinding() command:configureSAMLBinding("PARTNER", "PARTNER_TYPE", binding, ssoResponseBinding="httppost") Replace PARTNER with the Partner name Replace PARTNER_TYPE with the Partner type (idp or sp) Replace binding with the binding to be used to send the AuthnRequest and LogoutRequest/LogoutResponse messages (should be httpredirect in most case; default) httppost for HTTP-POST binding httpredirect for HTTP-Redirect binding Specify optionally ssoResponseBinding to indicate how the SSO Assertion should be sent back httppost for HTTP-POST binding artifactfor for Artifact binding An example would be:configureSAMLBinding("AcmeIdP", "idp", "httpredirect", ssoResponseBinding="httppost") Exit the WLST environment:exit() Test In this test, OIF/SP is integrated with a remote SAML 2.0 IdP Partner, with the OOTB configuration which requests HTTP-POST from the IdP to send the SSO Assertion. Based on this setup, when OIF/SP starts a Federation SSO flow, the following SAML 2.0 AuthnRequest would be generated: <samlp:AuthnRequest ProtocolBinding="urn:oasis:names:tc:SAML:2.0:bindings:HTTP-POST" ID="id-E4BOT7lwbYK56lO57dBaqGUFq01WJSjAHiSR60Q4" Version="2.0" IssueInstant="2014-04-01T21:39:14Z" Destination="https://acme.com/saml20/sso">   <saml:Issuer Format="urn:oasis:names:tc:SAML:2.0:nameid-format:entity">https://sp.com/oam/fed</saml:Issuer>   <samlp:NameIDPolicy AllowCreate="true"/></samlp:AuthnRequest> In the next article, I will cover the various crypto configuration properties in OIF that are used to affect the Federation SSO exchanges.Cheers,Damien Carru

    Read the article

  • Async CTP (C# 5): How to make WCF work with Async CTP

    - by javarg
    If you have recently downloaded the new Async CTP you will notice that WCF uses Async Pattern and Event based Async Pattern in order to expose asynchronous operations. In order to make your service compatible with the new Async/Await Pattern try using an extension method similar to the following: WCF Async/Await Method public static class ServiceExtensions {     public static Task<DateTime> GetDateTimeTaskAsync(this Service1Client client)     {         return Task.Factory.FromAsync<DateTime>(             client.BeginGetDateTime(null, null),             ar => client.EndGetDateTime(ar));     } } The previous code snippet adds an extension method to the GetDateTime method of the Service1Client WCF proxy. Then used it like this (remember to add the extension method’s namespace into scope in order to use it): Code Snippet var client = new Service1Client(); var dt = await client.GetDateTimeTaskAsync(); Replace the proxy’s type and operation name for the one you want to await.

    Read the article

  • Problem when using ajax for refresh captcha with refresh button [closed]

    - by jowan
    But it doesn't work, I just get my image be vanished and I try METHOD 2, I think it can work but I'm wrong coz i just get display with code of image not new captcha image I am stack and confuse about what method exactly work to refresh my own captcha.. Any wrong in my code or my method can't be used to refresh captcha.. Could anyone tell me how to refresh captcha exactly ? Thanks in Advance JQUERY CODE $('.refresh_captcha').click( function(){ $.ajax({ type: 'POST', url: 'captcha_mk.php', success: function(data){ //$('img').attr('src', data); // METHOD 1 ( I try it and my image is lost ) $('div').html('<img src=' + data); // METHOD 2 ( display code of image not captcha image) } }); });

    Read the article

  • RIDC Accelerator for Portal

    - by Stefan Krantz
    What is RIDC?Remote IntraDoc Client is a Java enabled API that leverages simple transportation protocols like Socket, HTTP and JAX/WS to execute content service operations in WebCenter Content Server. Each operation by design in the Content Server will execute stateless and return a complete result of the request. Each request object simply specifies the in a Map format (key and value pairs) what service to call and what parameters settings to apply. The result responded with will be built on the same Map format (key and value pairs). The possibilities with RIDC is endless since you can consume any available service (even custom made ones), RIDC can be executed from any Java SE application that has any WebCenter Content Services needs. WebCenter Portal and the example Accelerator RIDC adapter frameworkWebCenter Portal currently integrates and leverages WebCenter Content Services to enable available use cases in the portal today, like Content Presenter and Doc Lib. However the current use cases only covers few of the scenarios that the Content Server has to offer, in addition to the existing use cases it is not rare that the customer requirements requires additional steps and functionality that is provided by WebCenter Content but not part of the use cases from the WebCenter Portal.The good news to this is RIDC, the second good news is that WebCenter Portal already leverages the RIDC and has a connection management framework in place. The million dollar question here is how can I leverage this infrastructure for my custom use cases. Oracle A-Team has during its interactions produced a accelerator adapter framework that will reuse and leverage the existing connections provisioned in the webcenter portal application (works for WebCenter Spaces as well), as well as a very comprehensive design patter to minimize the work involved when exposing functionality. Let me introduce the RIDCCommon framework for accelerating WebCenter Content consumption from WebCenter Portal including Spaces. How do I get started?Through a few easy steps you will be on your way, Extract the zip file RIDCCommon.zip to the WebCenter Portal Application file structure (PortalApp) Open you Portal Application in JDeveloper (PS4/PS5) select to open the project in your application - this will add the project as a member of the application Update the Portal project dependencies to include the new RIDCCommon project Make sure that you WebCenter Content Server connection is marked as primary (a checkbox at the top of the connection properties form) You should by this stage have a similar structure in your JDeveloper Application Project Portal Project PortalWebAssets Project RIDCCommon Since the API is coming with some example operations that has already been exposed as DataControl actions, if you open Data Controls accordion you should see following: How do I implement my own operation? Create a new Java Class in for example com.oracle.ateam.portal.ridc.operation call it (GetDocInfoOperation) Extend the abstract class com.oracle.ateam.portal.ridc.operation.RIDCAbstractOperation and implement the interface com.oracle.ateam.portal.ridc.operation.IRIDCOperation The only method you actually are required to implement is execute(RIDCManager, IdcClient, IdcContext) The best practice to set object references for the operation is through the Constructor, example below public GetDocInfoOperation(String dDocName)By leveraging the constructor you can easily force the implementing class to pass right information, you can also overload the Constructor with more or less parameters as required Implement the execute method, the work you supposed to execute here is creating a new request binder and retrieve a response binder with the information in the request binder.In this case the dDocName for which we want the DocInfo Secondly you have to process the response binder by extracting the information you need from the request and restore this information in a simple POJO Java BeanIn the example below we do this in private void processResult(DataBinder responseData) - the new SearchDataObject is a Member of the GetDocInfoOperation so we can return this from a access method. Since the RIDCCommon API leverage template pattern for the operations you are now required to add a method that will enable access to the result after the execution of the operationIn the example below we added the method public SearchDataObject getDataObject() - this method returns the pre processed SearchDataObject from the execute method  This is it, as you can see on the code below you do not need more than 32 lines of very simple code 1: public class GetDocInfoOperation extends RIDCAbstractOperation implements IRIDCOperation { 2: private static final String DOC_INFO_BY_NAME = "DOC_INFO_BY_NAME"; 3: private String dDocName = null; 4: private SearchDataObject sdo = null; 5: 6: public GetDocInfoOperation(String dDocName) { 7: super(); 8: this.dDocName = dDocName; 9: } 10:   11: public boolean execute(RIDCManager manager, IdcClient client, 12: IdcContext userContext) throws Exception { 13: DataBinder dataBinder = createNewRequestBinder(DOC_INFO_BY_NAME); 14: dataBinder.putLocal(DocumentAttributeDef.NAME.getName(), dDocName); 15: 16: DataBinder responseData = getResponseBinder(dataBinder); 17: processResult(responseData); 18: return true; 19: } 20: 21: private void processResult(DataBinder responseData) { 22: DataResultSet rs = responseData.getResultSet("DOC_INFO"); 23: for(DataObject dobj : rs.getRows()) { 24: this.sdo = new SearchDataObject(dobj); 25: } 26: super.setMessage(responseData.getLocal(ATTR_MESSAGE)); 27: } 28: 29: public SearchDataObject getDataObject() { 30: return this.sdo; 31: } 32: } How do I execute my operation? In the previous section we described how to create a operation, so by now you should be ready to execute the operation Step one either add a method to the class  com.oracle.ateam.portal.datacontrol.ContentServicesDC or a class of your own choiceRemember the RIDCManager is a very light object and can be created where needed Create a method signature look like this public SearchDataObject getDocInfo(String dDocName) throws Exception In the method body - create a new instance of GetDocInfoOperation and meet the constructor requirements by passing the dDocNameGetDocInfoOperation docInfo = new GetDocInfoOperation(dDocName) Execute the operation via the RIDCManager instance rMgr.executeOperation(docInfo) Return the result by accessing it from the executed operationreturn docInfo.getDataObject() 1: private RIDCManager rMgr = null; 2: private String lastOperationMessage = null; 3:   4: public ContentServicesDC() { 5: super(); 6: this.rMgr = new RIDCManager(); 7: } 8: .... 9: public SearchDataObject getDocInfo(String dDocName) throws Exception { 10: GetDocInfoOperation docInfo = new GetDocInfoOperation(dDocName); 11: boolean boolVal = rMgr.executeOperation(docInfo); 12: lastOperationMessage = docInfo.getMessage(); 13: return docInfo.getDataObject(); 14: }   Get the binaries! The enclosed code in a example that can be used as a reference on how to consume and leverage similar use cases, user has to guarantee appropriate quality and support.  Download link: https://blogs.oracle.com/ATEAM_WEBCENTER/resource/stefan.krantz/RIDCCommon.zip RIDC API Referencehttp://docs.oracle.com/cd/E23943_01/apirefs.1111/e17274/toc.htm

    Read the article

  • SQL SERVER – Puzzle to Win Print Book – Explain Value of PERCENTILE_CONT() Using Simple Example

    - by pinaldave
    From last several days I am working on various Denali Analytical functions and it is indeed really fun to refresh the concept which I studied in the school. Earlier I wrote article where I explained how we can use PERCENTILE_CONT() to find median over here SQL SERVER – Introduction to PERCENTILE_CONT() – Analytic Functions Introduced in SQL Server 2012. Today I am going to ask question based on the same blog post. Again just like last time the intention of this puzzle is as following: Learn new concept of SQL Server 2012 Learn new concept of SQL Server 2012 even if you are on earlier version of SQL Server. On another note, SQL Server 2012 RC0 has been announced and available to download SQL SERVER – 2012 RC0 Various Resources and Downloads. Now let’s have fun following query: USE AdventureWorks GO SELECT SalesOrderID, OrderQty, ProductID, PERCENTILE_CONT(0.5) WITHIN GROUP (ORDER BY ProductID) OVER (PARTITION BY SalesOrderID) AS MedianCont FROM Sales.SalesOrderDetail WHERE SalesOrderID IN (43670, 43669, 43667, 43663) ORDER BY SalesOrderID DESC GO The above query will give us the following result: The reason we get median is because we are passing value .05 to PERCENTILE_COUNT() function. Now run read the puzzle. Puzzle: Run following T-SQL code: USE AdventureWorks GO SELECT SalesOrderID, OrderQty, ProductID, PERCENTILE_CONT(0.9) WITHIN GROUP (ORDER BY ProductID) OVER (PARTITION BY SalesOrderID) AS MedianCont FROM Sales.SalesOrderDetail WHERE SalesOrderID IN (43670, 43669, 43667, 43663) ORDER BY SalesOrderID DESC GO Observe the result and you will notice that MidianCont has different value than before, the reason is PERCENTILE_CONT function has 0.9 value passed. For first four value the value is 775.1. Now run following T-SQL code: USE AdventureWorks GO SELECT SalesOrderID, OrderQty, ProductID, PERCENTILE_CONT(0.1) WITHIN GROUP (ORDER BY ProductID) OVER (PARTITION BY SalesOrderID) AS MedianCont FROM Sales.SalesOrderDetail WHERE SalesOrderID IN (43670, 43669, 43667, 43663) ORDER BY SalesOrderID DESC GO Observe the result and you will notice that MidianCont has different value than before, the reason is PERCENTILE_CONT function has 0.1 value passed. For first four value the value is 709.3. Now in my example I have explained how the median is found using this function. You have to explain using mathematics and explain (in easy words) why the value in last columns are 709.3 and 775.1 Hint: SQL SERVER – Introduction to PERCENTILE_CONT() – Analytic Functions Introduced in SQL Server 2012 Rules Leave a comment with your detailed answer by Nov 25's blog post. Open world-wide (where Amazon ships books) If you blog about puzzle’s solution and if you win, you win additional surprise gift as well. Prizes Print copy of my new book SQL Server Interview Questions Amazon|Flipkart If you already have this book, you can opt for any of my other books SQL Wait Stats [Amazon|Flipkart|Kindle] and SQL Programming [Amazon|Flipkart|Kindle]. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL Function, SQL Puzzle, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, T SQL, Technology

    Read the article

  • SQL SERVER – Introduction to FIRST _VALUE and LAST_VALUE – Analytic Functions Introduced in SQL Server 2012

    - by pinaldave
    SQL Server 2012 introduces new analytical functions FIRST_VALUE() and LAST_VALUE(). This function returns first and last value from the list. It will be very difficult to explain this in words so I’d like to attempt to explain its function through a brief example. Instead of creating a new table, I will be using the AdventureWorks sample database as most developers use that for experiment purposes. Now let’s have fun following query: USE AdventureWorks GO SELECT s.SalesOrderID,s.SalesOrderDetailID,s.OrderQty, FIRST_VALUE(SalesOrderDetailID) OVER (ORDER BY SalesOrderDetailID) FstValue, LAST_VALUE(SalesOrderDetailID) OVER (ORDER BY SalesOrderDetailID) LstValue FROM Sales.SalesOrderDetail s WHERE SalesOrderID IN (43670, 43669, 43667, 43663) ORDER BY s.SalesOrderID,s.SalesOrderDetailID,s.OrderQty GO The above query will give us the following result: What’s the most interesting thing here is that as we go from row 1 to row 10, the value of the FIRST_VALUE() remains the same but the value of the LAST_VALUE is increasing. The reason behind this is that as we progress in every line – considering that line and all the other lines before it, the last value will be of the row where we are currently looking at. To fully understand this statement, see the following figure: This may be useful in some cases; but not always. However, when we use the same thing with PARTITION BY, the same query starts showing the result which can be easily used in analytical algorithms and needs. Let us have fun through the following query: Let us fun following query. USE AdventureWorks GO SELECT s.SalesOrderID,s.SalesOrderDetailID,s.OrderQty, FIRST_VALUE(SalesOrderDetailID) OVER (PARTITION BY SalesOrderID ORDER BY SalesOrderDetailID) FstValue, LAST_VALUE(SalesOrderDetailID) OVER (PARTITION BY SalesOrderID ORDER BY SalesOrderDetailID) LstValue FROM Sales.SalesOrderDetail s WHERE SalesOrderID IN (43670, 43669, 43667, 43663) ORDER BY s.SalesOrderID,s.SalesOrderDetailID,s.OrderQty GO The above query will give us the following result: Let us understand how PARTITION BY windows the resultset. I have used PARTITION BY SalesOrderID in my query. This will create small windows of the resultset from the original resultset and will follow the logic or FIRST_VALUE and LAST_VALUE in this resultset. Well, this is just an introduction to these functions. In the future blog posts we will go deeper to discuss the usage of these two functions. By the way, these functions can be applied over VARCHAR fields as well and are not limited to the numeric field only. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL Function, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, T SQL, Technology

    Read the article

  • Understanding the static keyword

    - by user985482
    I have some experience in developing with Java, Javascript and PHP. I am reading Microsoft Visual C# 2010 Step by Step which I feel it is a very good book on introducing you to the C# language. I seem to be having problems in understanding the static keyword. From what I understand this far if a class is declared static all methods and variable have to be static. The main method always is a static method so in the class that the main method exists all variables and methods are declared static if you have to call them in the main method. Also I have noticed that in order to call a static method from another class you do not need to create an object of that you can use the class name. What are the advantages of declaring static variables and methods? When should I declare static variable and methods?

    Read the article

  • Saving game data to server [on hold]

    - by Eugene Lim
    What's the best method to save the player's data to the server? Method to store the game saves Which one of the following method should I use ? Using a database structure(e.g.. mySQL) to store the game data as blobs? Using the server hard disk to store the saved game data as binary data files? Method to send saved game data to server What method should I use ? socketIO web socket a web-based scripting language to receive the game data as binary? for example, a php script to handle binary data and save it to file Meta-data I read that some games store saved game meta-data in database structures. What kind of meta data is useful to store?

    Read the article

  • How to create a PeopleCode Application Package/Application Class using PeopleTools Tables

    - by Andreea Vaduva
    This article describes how - in PeopleCode (Release PeopleTools 8.50) - to enable a grid without enabling each static column, using a dynamic Application Class. The goal is to disable the following grid with three columns “Effort Date”, ”Effort Amount” and “Charge Back” , when the Check Box “Finished with task” is selected , without referencing each static column; this PeopleCode could be used dynamically with any grid. If the check box “Finished with task” is cleared, the content of the grid columns is editable (and the buttons “+” and “-“ are available): So, you create an Application Package “CLASS_EXTENSIONS” that contains an Application Class “EWK_ROWSET”. This Application Class is defined with Class extends “ Rowset” and you add two news properties “Enabled” and “Visible”: After creating this Application Class, you use it in two PeopleCode Events : Rowinit and FieldChange : This code is very ‘simple’, you write only one command : ” &ERS2.Enabled = False” → and the entire grid is “Enabled”… and you can use this code with any Grid! So, the complete PeopleCode to create the Application Package is (with explanation in [….]) : ******Package CLASS_EXTENSIONS : [Name of the Package: CLASS_EXTENSIONS] --Beginning of the declaration part------------------------------------------------------------------------------ class EWK_ROWSET extends Rowset; [Definition Class EWK_ROWSET as a subclass of Class Rowset] method EWK_ROWSET(&RS As Rowset); [Constructor is the Method with the same name of the Class] property boolean Visible get set; property boolean Enabled get set; [Definition of the property “Enabled” in read/write] private [Before the word “private”, all the declarations are publics] method SetDisplay(&DisplaySW As boolean, &PropName As string, &ChildSW As boolean); instance boolean &EnSW; instance boolean &VisSW; instance Rowset &NextChildRS; instance Row &NextRow; instance Record &NextRec; instance Field &NextFld; instance integer &RowCnt, &RecCnt, &FldCnt, &ChildRSCnt; instance integer &i, &j, &k; instance CLASS_EXTENSIONS:EWK_ROWSET &ERSChild; [For recursion] Constant &VisibleProperty = "VISIBLE"; Constant &EnabledProperty = "ENABLED"; end-class; --End of the declaration part------------------------------------------------------------------------------ method EWK_ROWSET [The Constructor] /+ &RS as Rowset +/ %Super = &RS; end-method; get Enabled /+ Returns Boolean +/; Return &EnSW; end-get; set Enabled /+ &NewValue as Boolean +/; &EnSW = &NewValue; %This.InsertEnabled=&EnSW; %This.DeleteEnabled=&EnSW; %This.SetDisplay(&EnSW, &EnabledProperty, False); [This method is called when you set this property] end-set; get Visible /+ Returns Boolean +/; Return &VisSW; end-get; set Visible /+ &NewValue as Boolean +/; &VisSW = &NewValue; %This.SetDisplay(&VisSW, &VisibleProperty, False); end-set; method SetDisplay [The most important PeopleCode Method] /+ &DisplaySW as Boolean, +/ /+ &PropName as String, +/ /+ &ChildSW as Boolean +/ [Not used in our example] &RowCnt = %This.ActiveRowCount; &NextRow = %This.GetRow(1); [To know the structure of a line ] &RecCnt = &NextRow.RecordCount; For &i = 1 To &RowCnt [Loop for each Line] &NextRow = %This.GetRow(&i); For &j = 1 To &RecCnt [Loop for each Record] &NextRec = &NextRow.GetRecord(&j); &FldCnt = &NextRec.FieldCount; For &k = 1 To &FldCnt [Loop for each Field/Record] &NextFld = &NextRec.GetField(&k); Evaluate Upper(&PropName) When = &VisibleProperty &NextFld.Visible = &DisplaySW; Break; When = &EnabledProperty; &NextFld.Enabled = &DisplaySW; [Enable each Field/Record] Break; When-Other Error "Invalid display property; Must be either VISIBLE or ENABLED" End-Evaluate; End-For; End-For; If &ChildSW = True Then [If recursion] &ChildRSCnt = &NextRow.ChildCount; For &j = 1 To &ChildRSCnt [Loop for each Rowset child] &NextChildRS = &NextRow.GetRowset(&j); &ERSChild = create CLASS_EXTENSIONS:EWK_ROWSET(&NextChildRS); &ERSChild.SetDisplay(&DisplaySW, &PropName, &ChildSW); [For each Rowset child, call Method SetDisplay with the same parameters used with the Rowset parent] End-For; End-If; End-For; end-method; ******End of the Package CLASS_EXTENSIONS:[Name of the Package: CLASS_EXTENSIONS] About the Author: Pascal Thaler joined Oracle University in 2005 where he is a Senior Instructor. His area of expertise is Oracle Peoplesoft Technology and he delivers the following courses: For Developers: PeopleTools Overview, PeopleTools I &II, Batch Application Engine, Language Oriented Object PeopleCode, Administration Security For Administrators : Server Administration & Installation, Database Upgrade & Data Management Tools For Interface Users: Integration Broker (Web Service)

    Read the article

  • Drawing graphics in Java game

    - by wolf
    I am quite new to game development, so here is a question (maybe a stupid one): In my sidescroller i have a bunch of different graphics objects that i need to draw (player, background tiles, creatures, projectiles etc). Most tutorials i've read so far show that each object has its own draw method, which is then called from some other method. What if I had one method that does all the drawing? Lets say i keep all my objects in an array or queue (or multiple arrays) and then go through each of them, get an image and draw it. So basically would it be better (and why) to have each object have its own draw method or one method that does all the drawing? Or does it matter at all? I feel like the second option is more comfortable, because then all the stuff to do with drawing would be in one place...

    Read the article

  • Guidance on building an au pair-to-family networking site.

    - by Philip Kidd
    I'm building a website for an au pair agency business that will connect au pairs to families around Europe. I know nothing about website building, HTML etc. so I'm using a wysiwyg editer (weebly). How I would like the site to function: Families upload their information into profiles Au pairs do the same families can view a limited part of an au pairs' profile until they pay a deposit After deposit is payed, all au pairs' profile information becomes open to families Families can order au pairs and confirm their order with another payment payment must be made before 'order' is confirmed By 'order' I mean full communications become open between the family and the au pair they have 'ordered' as well as travel information being sent to another agency the site needs to be linked with a bank account (e.g paypal) and another agency, who will look after the flight bookings etc. A website already exists for this business however it just contains information on the business and application forms - if the site becomes fully automated it will relieve a lot of strain on administration in the office (dealing with applications, travel information etc.)

    Read the article

  • SQL SERVER – Recover the Accidentally Renamed Table

    - by pinaldave
    I have no answer to following question. I saw a desperate email marked as urgent delivered in my mailbox. “I accidentally renamed table in my SSMS. I was scrolling very fast and I made mistakes. It was either because I double clicked or clicked on F2 (shortcut key for renaming). However, I have made the mistake and now I have no idea how to fix this. I am in big trouble. Help me get my original tablename.” I have seen many similar scenarios in my life and they give me a very good opportunity to preach wisdom but when the house is burning, we cannot talk about how we should have conserved the water earlier. The goal at that point is to put off the fire as fast as we can. I decided to answer this email with my best knowledge. If you have renamed the table, I think you pretty much is out of luck. Here are few things which you can do which can give you idea about what your tablename can be if you are lucky. Method 1: (Not Recommended but try your luck) Check your naming convention of your system. I have often seen that many organizations name their index as IX_TableName_Colms or name their keys as FK_TableName1_TableName2_Cols. If your organization is following the same you can get the name from your table, you may refer your keys. Again, note that this is quite possible that your tablename was already renamed and your keys were not updated. This can easily lead you to select incorrect name. I think follow this if you are confident or move to the next method. Method 2: (Not Recommended but try your luck) This method is also based on your orgs naming convention. If you use the name of the table in any columnname (some organizations use tablename in their incremental identity column name), you can get that name from there. Method 3: (Not Recommended but try your luck) If you know where your table was used in your stored procedures, you can script your stored procedure and find the name of the table back. Method 4: (Try your luck) All the best organizations first create a data model of the schema and there is good chance that this table is used there, you should take your chances and refer original document. If your organization is good at managing docs or source code, you will get the name of the table back for sure. Method 5: (It WORKS but try on a development server) There is no sure way to get you the name of the table which you accidentally renamed however, there is one way which will work for sure. You need to take your latest full backup and restore it on your development server (remember not on production or where you have renamed this column). Now restore latest differential file of the full backup. Now restore all the log files one by one making sure that you are restoring before the point of time of you renamed the tablename. Now go to explore and this will give you the name of the table which you have renamed. If you are confident that the same table existed with the same name when the last full backup was made, you do not have to go to all the steps. You can just get the name of the table directly from last backup’s restore. Read the article about Backup Timeline. Wisdom: How can I miss to preach wisdom when I get the opportunity to do so? Here are a few points to remember. Use a different account to explore production environment. Do not use the same account which have all the rights and permissions all the time. Use the account which has read only permissions if there are no modification required. Use policy based management to prevent changes which are accidental. If there was policy of valid names, the accidental change of the table was not possible unless it was intentional delibarate changes. Have a proper auditing of the system in place. You can use DDL triggers but be careful with its usage (get it reviewed properly first). (Add your suggestion here) I guess Method 5 will work all the time (using point in time restore). Everything else is chance of luck and if you are lucky are bad – you will get further incorrect name. Now go back and read the first line of this blog. Out of five method four methods are just lucky guesses. The method 5 will work but again it is a lengthy process if the size of the database is huge or if you do not have full backup. Did I miss anything obvious? Please leave a comment and I will publish your answer with due credit. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Puzzle, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

    Read the article

  • How to write reusable code in node.js

    - by lortabac
    I am trying to understand how to design node.js applications, but it seems there is something I can't grasp about asynchronous programming. Let's say my application needs to access a database. In a synchronous environment I would implement a data access class with a read() method, returning an associative array. In node.js, because code is executed asynchronously, this method can't return a value, so, after execution, it will have to "do" something as a side effect. It will then contain some code which does something else than just reading data. Let's suppose I want to call this method multiple times, each time with a different success callback. Since the callback is included in the method itself, I can't find a clean way to do this without either duplicating the method or specifying all possible callbacks in a long switch statement. What is the proper way to handle this problem? Am I approaching it the wrong way?

    Read the article

  • SL150 Modular Tape Library Demo Equipment Purchase Opportunity Limited Special Pricing on Demo Configuration

    - by Cinzia Mascanzoni
    Oracle is pleased to announce that, for a limited time, Oracle VADs may purchase special SL150 Modular Tape Library configurations for demonstration purposes at a significantly reduced price. Submit your order today for these special SL150 Modular Tape Library configurations and you can start showcasing these products in partner demonstrations and proof-of-concepts. VADs may also sell demo units to their VARs so that they may use them in their customer evaluations to help shorten the sales cycle. The offer also allows VARs to sell the demo configuration after a prescribed demonstration period to support the demo product’s cost of ownership. Why wait? Order today! Rules and Guidelines Only authorized VADs are allowed to purchase the special SL150 Modular Tape Library configurations. Purchase time frame is from now until February 28, 2013. Only the predetermined configurations are approved for purchase at the prescribed discounts. Supply is allocated per region and it’s limited. Order MUST be placed via the Oracle Partner Store* (OPS) where applicable. See below for online and offline order processes. If reselling to a VAR, VAD must include the Partner Demonstration Hardware Terms with the order (online via OPS or with offline VAD Ordering Document). Please mark your calendars for the SL150 Modular Tape Library Demo Program webcast on Sept 5th. The objective of this call is to share the details of this demo program with you. For details on how to connect to the webcast, contact your VAD Manager

    Read the article

  • Should I add parameters to instance methods that use those instance fields as parameters?

    - by john smith optional
    I have an instance method that uses instance fields in its work. I can leave the method without that parameters as they're available to me, or I can add them to the parameter list, thus making my method more "generic" and not reliable on the class. On the other hand, additional parameters will be in parameters list. Which approach is preferable and why? Edit: at the moment I don't know if my method will be public or private. Edit2: clarification: both method and fields are instance level.

    Read the article

  • My Dog, Cross-Channel Shopping, and Fusion SCM

    - by Kathryn Perry
    A guest post by Mark Carson, Director, Oracle Fusion Supply Chain Management I was walking my dog Max in an open space behind my house. As we tromped through the tall weeds I remembered it is tick season and that I should get Max some protection. While he sniffed merrily in the tick infested brush, I started shopping in the middle of an open field on my phone. I thought it would be convenient to pick up the tick medicine from a pet store on the way home. Searching the pet store website I saw that they had the medicine, but there was no information on whether the store had any in stock and there were no options for shipping it to the store for pickup. I could return it, but not pick it up which seamed kind of odd. I really didn't feel like making calls to the local stores to find out if they had it. Since the product is popular, I tried one of the large 'everything' stores. Browsing its website I could see that it could be shipped to me, shipped to the store for free, and that the store nearest to me had it in stock. Needless to say, this store became a better option. This experience is a small example of why retailers, distributors, and manufactures have placed a high priority on enabling 'cross-channel commerce.' Shoppers like you and me expect to be able to search, compare, buy and return products on-line and over the phone using a variety of devices including PDAs, tablets and in-store kiosks. The pet store lost my business because its web channel had limited information about its stores. I have spoken with many customers and prospects about cross-channel commerce. They all realize the business implications and urgency behind cross-channel commerce but recognize there are challenges to enable it. New and existing applications must be integrated together globally through a consistent cross-channel business process. Integration is required between applications that provide the initial shopping experience and delivery applications associated with warehouses, stores, and partners. The enablement must be accomplished in a flexible way to react to fast-changing product portfolios and new acquisitions, while at the same time minimizing costs through reuse of existing systems. Meanwhile, the business must continue to grow and decision makers need to balance new capability with peak seasons. The challenges above are not unique to retail. Any customer in any industry who has multiple points for capturing orders and multiple points for fulfilling orders will face these challenges. With this in mind, we had a unique opportunity in Fusion SCM to re-think how to build a set of modular and flexible applications in the order management space that would make these challenges easier to conquer. The results are Fusion Distributed Order Orchestration and Global Order Promising. These applications can help companies, such as the pet store, enable true cross-channel commerce. The apps provide highly adaptable and flexible business processes to automate order orchestration across multiple cross-channel systems. They also show a global view of supply across warehouses, stores, and partners for real-time availability and more accurate order promising. Additional capability includes a standards-based integration framework for seamless execution and the ability to reuse existing systems for faster and lower cost implementations. OK, that was a mouthful of features and benefits. As Max waited to cross the street (he can do basic math too), I wondered if he could relate. He does not care about leash laws, pick-up courtesy, where he can/can't walk, what time of day it is, or even ticks. He does not care about how all these things could make walking complicated. He just wants to walk. Similarly, customers just want to shop and companies just want to make it easier to sell and deliver. You can learn more about Distributed Order Orchestration and Global Order Promising in cross-channel here.

    Read the article

  • Localization in php, best practice or approach?

    - by sree
    I am Localizing my php application. I have a dilemma on choosing best method to accomplish the same. Method 1: Currently am storing words to be localized in an array in a php file <?php $values = array ( 'welcome' => 'bienvenida' ); ?> I am using a function to extract and return each word according to requirement Method 2: Should I use a txt file that stores string of the same? <?php $welcome = 'bienvenida'; ?> My question is which is a better method, in terms of speed and effort to develop the same and why? Edit: I would like to know which method out of two is faster in responding and why would that be? also, any improvement on the above code would be appreciated!!

    Read the article

  • Facebook: Sending private messages to FB profile from a static website [migrated]

    - by Frondor
    I need to setup a static website for people to: Complete a form. And using anything from Facebook API, GET the form output via message to a Facebook Profile. I've been punching my head against "facebook developers" page all night long and can't find out how to do it. Seems quite easy, but the problem is that I don't know if you'll get my point :) Like the Send Dialog feature, you can set a certain user as recipient which will be displayed on the "To:" field once the dialog appears. FB.ui({ method: 'send', to: 'UserID', link: 'http://www.nytimes.com/2011/06/15/arts/people-argue-just-to-win-scholars-assert.html', }); Ok, All I need is to be able to use the same behavior but instead of setting a "to:" parameter, I'd like to set a "message:" parameter. I don't know how I can solve this becuase there's no parameter like this on the API actually. This is what I need to build (It's a prototype, this code won't work) <form action="mysite.com" id="order"> <input type="radio" name="chocolate" value="white">White <br/> <input type="radio" name="chocolate" value="black">Black <br/> <input type="submit" value="Order" /> </form> jQuery gets the values $(document).ready(function() { $("#order").on("submit", function(e) { e.preventDefault(); var formOutput = $(this).serialize(); var order = "I'd like to eat" + formOutput + "chocolate"; }); }); Facebook sdk sends this output ('order' string) FB.ui({ method: 'send', //or whatever to: 'UserID', message: order, //Its just an example, note the variable coming from the form link: 'http://www.nytimes.com/2011/06/15/arts/people-argue-just-to-win-scholars-assert.html', }); As we all know, what I wrote isn't possible, so I'm asking for any alternative solution if somebody can give me, I'm not very friendly with facebook APIs :) I though in another solution which consist in using the form output directly on the 'link:' parameter of FB.ui and then reading it with jQuery on some landing page. For example, on the message sent, the linked content redirects to this URL: http://mysite.com/dashboard.html?chocolate=white and the dashboard page source code: <script> var choco = getUrlParameter('chocolate'); $("#dashboard").text("This person wants" + choco + "chocolate") </script> <div id="dashboard"></div> And this way, I will be able to see which kind of chocolate the person selected by parsing some parameters on the URL when clicking on the link section of the message: using a code like this: FB.ui({ method: 'send', //or whatever to: 'MyUserID', link: 'http://mysite.com/dashboard.html?chocolate=white', }); But no this try, my biggest problem is that I don't know how to dynamically "customize" that "link:" paramenter with jQuery. I think the best solution is to use a code like this along with the dashboard page in order to "translate" the shared URLs and see what kind of chocolate people are demanding xD FB.ui({ //declaring a variable (example) var string = getFormData().serialize; var orderString = "mysite.com/dashboard.html?" + string; // end the variables // start facebook API code method: 'send', //or whatever to: 'MyUserID', link: orderString, }); I was working here until I gave up and started to post this http://jsfiddle.net/Frondor/sctepn06/2/ Thanks in advance, I'll love you for ever if you help me solving this :D

    Read the article

  • Object oriented EDI handling in PHP

    - by Robert van der Linde
    I'm currently starting a new sub project where I will: Retrieve the order information from our mainframe Save the order information to our web-apps' database Send the order as EDI (either D01b or D93a) Receive the order response, despatch advice and invoice messages Do all kinds of fun things with the resulting datasets. However I am struggling with my initial class designs. The order information will be retrieved from the mainframe which will result in a "AOrder" class, this isn't a problem, I am not sure about how to mold this local object into an EDI string. Should I create EDIOrder/EDIOrderResponse/etc classes with matching decorators (EDIOrderD01BDecorator, EDIOrderD93ADecorator)? Do I need builder objects or can I do: // $myOrder is instance of AOrder $myOrder->toEDIOrder(); $decorator = new EDIOrderD01BDecorator($myOrder); $edi = $decorator->getEDIString(); And it'll have to work the other way around as well. Is the following code a good way of handling this problem or should I go about this differently? $ediString = $myEDIMessageBroker->fetch(); $ediOrderResponse = EDIOrderResponse::fromString($ediString); I'm just not so sure about how I should go about designing the classes and interactions between them. Thanks for reading and helping.

    Read the article

  • Vector with Constant-Time Remove - still a Vector?

    - by Darrel Hoffman
    One of the drawbacks of most common implementations of the Vector class (or ArrayList, etc. Basically any array-backed expandable list class) is that their remove() operation generally operates in linear time - if you remove an element, you must shift all elements after it one space back to keep the data contiguous. But what if you're using a Vector just to be a list-of-things, where the order of the things is irrelevant? In this case removal can be accomplished in a few simple steps: Swap element to be removed with the last element in the array Reduce size field by 1. (No need to re-allocate the array, as the deleted item is now beyond the size field and thus not "in" the list any more. The next add() will just overwrite it.) (optional) Delete last element to free up its memory. (Not needed in garbage-collected languages.) This is clearly now a constant-time operation, since only performs a single swap regardless of size. The downside is of course that it changes the order of the data, but if you don't care about the order, that's not a problem. Could this still be called a Vector? Or is it something different? It has some things in common with "Set" classes in that the order is irrelevant, but unlike a Set it can store duplicate values. (Also most Set classes I know of are backed by a tree or hash map rather than an array.) It also bears some similarity to Heap classes, although without the log(N) percolate steps since we don't care about the order.

    Read the article

  • Preseed Partman: multiple partitions on one disk /tmp /data /usr swap

    - by Moritz
    trying to get preseeding on 12.04 64bit with what should be a basic setup to work: /dev/sda - the only drive beeing used / - rootfs - 100GB /boot - 1GB /tmp - 10GB /data - should take all available space swap - 10GB - d-i partman-auto/expert_recipe string \ boot-root :: \ 1000 50 1000 ext4 \ $primary{ } $bootable{ } \ method{ format } format{ } \ use_filesystem{ } filesystem{ ext4 } \ mountpoint{ /boot } \ . \ 500 1000 10000 ext4 \ method{ format } format{ } \ use_filesystem{ } filesystem{ ext4 } \ mountpoint{ /tmp } \ . \ 500 5000 100000000 ext4 \ method{ format } format{ } \ use_filesystem{ } filesystem{ ext4 } \ mountpoint{ /data } \ . \ 64 2000 10000 linux-swap \ method{ swap } format{ } \ . \ 500 3000 100000 ext4 \ method{ format } format{ } \ use_filesystem{ } filesystem{ ext4 } \ mountpoint{ / } \ . If i only use the code for /boot,swap and / it works. Also i was wondering weather i have to specify some other recipe name than "boot-root", but trying "thisNameIsNotDefinedInPartman" the result was the same. The Error message displayed by the ubuntu installer is always "no root file system is defined" Thanks for your help, Moritz

    Read the article

  • Building Queries Systematically

    - by Jeremy Smyth
    The SQL language is a bit like a toolkit for data. It consists of lots of little fiddly bits of syntax that, taken together, allow you to build complex edifices and return powerful results. For the uninitiated, the many tools can be quite confusing, and it's sometimes difficult to decide how to go about the process of building non-trivial queries, that is, queries that are more than a simple SELECT a, b FROM c; A System for Building Queries When you're building queries, you could use a system like the following:  Decide which fields contain the values you want to use in our output, and how you wish to alias those fields Values you want to see in your output Values you want to use in calculations . For example, to calculate margin on a product, you could calculate price - cost and give it the alias margin. Values you want to filter with. For example, you might only want to see products that weigh more than 2Kg or that are blue. The weight or colour columns could contain that information. Values you want to order by. For example you might want the most expensive products first, and the least last. You could use the price column in descending order to achieve that. Assuming the fields you've picked in point 1 are in multiple tables, find the connections between those tables Look for relationships between tables and identify the columns that implement those relationships. For example, The Orders table could have a CustomerID field referencing the same column in the Customers table. Sometimes the problem doesn't use relationships but rests on a different field; sometimes the query is looking for a coincidence of fact rather than a foreign key constraint. For example you might have sales representatives who live in the same state as a customer; this information is normally not used in relationships, but if your query is for organizing events where sales representatives meet customers, it's useful in that query. In such a case you would record the names of columns at either end of such a connection. Sometimes relationships require a bridge, a junction table that wasn't identified in point 1 above but is needed to connect tables you need; these are used in "many-to-many relationships". In these cases you need to record the columns in each table that connect to similar columns in other tables. Construct a join or series of joins using the fields and tables identified in point 2 above. This becomes your FROM clause. Filter using some of the fields in point 1 above. This becomes your WHERE clause. Construct an ORDER BY clause using values from point 1 above that are relevant to the desired order of the output rows. Project the result using the remainder of the fields in point 1 above. This becomes your SELECT clause. A Worked Example   Let's say you want to query the world database to find a list of countries (with their capitals) and the change in GNP, using the difference between the GNP and GNPOld columns, and that you only want to see results for countries with a population greater than 100,000,000. Using the system described above, we could do the following:  The Country.Name and City.Name columns contain the name of the country and city respectively.  The change in GNP comes from the calculation GNP - GNPOld. Both those columns are in the Country table. This calculation is also used to order the output, in descending order To see only countries with a population greater than 100,000,000, you need the Population field of the Country table. There is also a Population field in the City table, so you'll need to specify the table name to disambiguate. You can also represent a number like 100 million as 100e6 instead of 100000000 to make it easier to read. Because the fields come from the Country and City tables, you'll need to join them. There are two relationships between these tables: Each city is hosted within a country, and the city's CountryCode column identifies that country. Also, each country has a capital city, whose ID is contained within the country's Capital column. This latter relationship is the one to use, so the relevant columns and the condition that uses them is represented by the following FROM clause:  FROM Country JOIN City ON Country.Capital = City.ID The statement should only return countries with a population greater than 100,000,000. Country.Population is the relevant column, so the WHERE clause becomes:  WHERE Country.Population > 100e6  To sort the result set in reverse order of difference in GNP, you could use either the calculation, or the position in the output (it's the third column): ORDER BY GNP - GNPOld or ORDER BY 3 Finally, project the columns you wish to see by constructing the SELECT clause: SELECT Country.Name AS Country, City.Name AS Capital,        GNP - GNPOld AS `Difference in GNP`  The whole statement ends up looking like this:  mysql> SELECT Country.Name AS Country, City.Name AS Capital, -> GNP - GNPOld AS `Difference in GNP` -> FROM Country JOIN City ON Country.Capital = City.ID -> WHERE Country.Population > 100e6 -> ORDER BY 3 DESC; +--------------------+------------+-------------------+ | Country            | Capital    | Difference in GNP | +--------------------+------------+-------------------+ | United States | Washington | 399800.00 | | China | Peking | 64549.00 | | India | New Delhi | 16542.00 | | Nigeria | Abuja | 7084.00 | | Pakistan | Islamabad | 2740.00 | | Bangladesh | Dhaka | 886.00 | | Brazil | Brasília | -27369.00 | | Indonesia | Jakarta | -130020.00 | | Russian Federation | Moscow | -166381.00 | | Japan | Tokyo | -405596.00 | +--------------------+------------+-------------------+ 10 rows in set (0.00 sec) Queries with Aggregates and GROUP BY While this system might work well for many queries, it doesn't cater for situations where you have complex summaries and aggregation. For aggregation, you'd start with choosing which columns to view in the output, but this time you'd construct them as aggregate expressions. For example, you could look at the average population, or the count of distinct regions.You could also perform more complex aggregations, such as the average of GNP per head of population calculated as AVG(GNP/Population). Having chosen the values to appear in the output, you must choose how to aggregate those values. A useful way to think about this is that every aggregate query is of the form X, Y per Z. The SELECT clause contains the expressions for X and Y, as already described, and Z becomes your GROUP BY clause. Ordinarily you would also include Z in the query so you see how you are grouping, so the output becomes Z, X, Y per Z.  As an example, consider the following, which shows a count of  countries and the average population per continent:  mysql> SELECT Continent, COUNT(Name), AVG(Population)     -> FROM Country     -> GROUP BY Continent; +---------------+-------------+-----------------+ | Continent     | COUNT(Name) | AVG(Population) | +---------------+-------------+-----------------+ | Asia          |          51 |   72647562.7451 | | Europe        |          46 |   15871186.9565 | | North America |          37 |   13053864.8649 | | Africa        |          58 |   13525431.0345 | | Oceania       |          28 |    1085755.3571 | | Antarctica    |           5 |          0.0000 | | South America |          14 |   24698571.4286 | +---------------+-------------+-----------------+ 7 rows in set (0.00 sec) In this case, X is the number of countries, Y is the average population, and Z is the continent. Of course, you could have more fields in the SELECT clause, and  more fields in the GROUP BY clause as you require. You would also normally alias columns to make the output more suited to your requirements. More Complex Queries  Queries can get considerably more interesting than this. You could also add joins and other expressions to your aggregate query, as in the earlier part of this post. You could have more complex conditions in the WHERE clause. Similarly, you could use queries such as these in subqueries of yet more complex super-queries. Each technique becomes another tool in your toolbox, until before you know it you're writing queries across 15 tables that take two pages to write out. But that's for another day...

    Read the article

  • Sleepyti.me Calculates an Ideal Bedtime Based On Your Morning Schedule

    - by Jason Fitzpatrick
    Sleepyti.me is a web-based sleep calculator that uses average sleep cycle lengths to calculate what time you should go to bed in order to rise at a predetermined well rested and alert. Plug in the time you need to wake up and hit Calculator. Sleepyti.me charts out the 90 minute sleep cycles that will occur over your sleep period and, working backwards, suggests time you should fall asleep in order to wake up in between those cycles in order to increase alertness and have an easier time peeling yourself out of bed. For example, let’s say you need to get up at 7:00 AM. It will suggest you fall asleep at 10:00 PM/11:30 PM/1:00 AM/2:30 AM in order to align your sleep cycles with your proposed rising time. Hit up the link below to take it for a spin. Sleepyti.me How to Own Your Own Website (Even If You Can’t Build One) Pt 3 How to Sync Your Media Across Your Entire House with XBMC How to Own Your Own Website (Even If You Can’t Build One) Pt 2

    Read the article

< Previous Page | 246 247 248 249 250 251 252 253 254 255 256 257  | Next Page >