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  • More efficient SQL than using "A UNION (B in A)"?

    - by machinatus
    Edit 1 (clarification): Thank you for the answers so far! The response is gratifying. I want to clarify the question a little because based on the answers I think I did not describe one aspect of the problem correctly (and I'm sure that's my fault as I was having a difficult time defining it even for myself). Here's the rub: The result set should contain ONLY the records with tstamp BETWEEN '2010-01-03' AND '2010-01-09', AND the one record where the tstamp IS NULL for each order_num in the first set (there will always be one with null tstamp for each order_num). The answers given so far appear to include all records for a certain order_num if there are any with tstamp BETWEEN '2010-01-03' AND '2010-01-09'. For example, if there were another record with order_num = 2 and tstamp = 2010-01-12 00:00:00 it should not be included in the result. Original question: Consider an orders table containing id (unique), order_num, tstamp (a timestamp), and item_id (the single item included in an order). tstamp is null, unless the order has been modified, in which case there is another record with identical order_num and tstamp then contains the timestamp of when the change occurred. Example... id order_num tstamp item_id __ _________ ___________________ _______ 0 1 100 1 2 101 2 2 2010-01-05 12:34:56 102 3 3 113 4 4 124 5 5 135 6 5 2010-01-07 01:23:45 136 7 5 2010-01-07 02:46:00 137 8 6 100 9 6 2010-01-13 08:33:55 105 What is the most efficient SQL statement to retrieve all of the orders (based on order_num) which have been modified one or more times during a certain date range? In other words, for each order we need all of the records with the same order_num (including the one with NULL tstamp), for each order_num WHERE at least one of the order_num's has tstamp NOT NULL AND tstamp BETWEEN '2010-01-03' AND '2010-01-09'. It's the "WHERE at least one of the order_num's has tstamp NOT NULL" that I'm having difficulty with. The result set should look like this: id order_num tstamp item_id __ _________ ___________________ _______ 1 2 101 2 2 2010-01-05 12:34:56 102 5 5 135 6 5 2010-01-07 01:23:45 136 7 5 2010-01-07 02:46:00 137 The SQL that I came up with is this, which is essentially "A UNION (B in A)", but it executes slowly and I hope there is a more efficient solution: SELECT history_orders.order_id, history_orders.tstamp, history_orders.item_id FROM (SELECT orders.order_id, orders.tstamp, orders.item_id FROM orders WHERE orders.tstamp BETWEEN '2010-01-03' AND '2010-01-09') AS history_orders UNION SELECT current_orders.order_id, current_orders.tstamp, current_orders.item_id FROM (SELECT orders.order_id, orders.tstamp, orders.item_id FROM orders WHERE orders.tstamp IS NULL) AS current_orders WHERE current_orders.order_id IN (SELECT orders.order_id FROM orders WHERE orders.tstamp BETWEEN '2010-01-03' AND '2010-01-09');

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  • Create non-persistent cookie with FormsAuthenticationTicket

    - by Marcus
    Hello! I'm having trouble creating a non-persistent cookie using the FormsAuthenticationTicket. I want to store userdata in the ticket, so i can't use FormsAuthentication.SetAuthCookie() or FormsAuthentication.GetAuthCookie() methods. Because of this I need to create the FormsAuthenticationTicket and store it in a HttpCookie. My code looks like this: DateTime expiration = DateTime.Now.AddDays(7); // Create ticket FormsAuthenticationTicket ticket = new FormsAuthenticationTicket(2, user.Email, DateTime.Now, expiration, isPersistent, userData, FormsAuthentication.FormsCookiePath); // Create cookie HttpCookie cookie = new HttpCookie(FormsAuthentication.FormsCookieName, FormsAuthentication.Encrypt(ticket)); cookie.Path = FormsAuthentication.FormsCookiePath; if (isPersistent) cookie.Expires = expiration; // Add cookie to response HttpContext.Current.Response.Cookies.Add(cookie); When the variable isPersistent is true everything works fine and the cookie is persisted. But when isPersistent is false the cookie seems to be persisted anyway. I sign on in a browser window, closes it and opens the browser again and I am still logged in. How do i set the cookie to be non-persistent? Is a non-persistent cookie the same as a session cookie? Is the cookie information stored in the sessiondata on the server or are the cookie transferred in every request/response to the server? Thanks in advance! /Marcus

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  • Marshal.StringToCoTaskMemAnsi converting non-Latin characters when sending raw data to a printer

    - by rem
    For sending raw data to a thermal DATAMAX printer I'm using RawPrinterHelper class from this Microsoft KB article. When a string sent to printer contains only Latin characters, everything is OK. But non-Latin, in my case Russian characters in a string, are not printed correct. I think the problem is in using Marshal.StringToCoTaskMemAnsi method for converting the string: public static bool SendStringToPrinter(string szPrinterName, string szString) { IntPtr pBytes; Int32 dwCount; // How many characters are in the string? dwCount = szString.Length; // Assume that the printer is expecting ANSI text, and then convert // the string to ANSI text. pBytes = Marshal.StringToCoTaskMemAnsi(szString); // Send the converted ANSI string to the printer. SendBytesToPrinter(szPrinterName, pBytes, dwCount); Marshal.FreeCoTaskMem(pBytes); return true; } Just to note, Russian characters in the string are put in hex format, like "\x83", but nevertheless the method doesn't put this hex value in unmanaged memory as it is, but converts it, I think, according with ANSI code page to a character and then printer can not read it correctly. If I try to compose a file, using Hex editor and put correct hex values in place of non-Latin characters and then send the file to a printer using another method from the same class SendFileToPrinter, everything, including Russian characters is printed correctly. How in this case the problem with sending string, containing non-Latin characters, could be solved?

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  • Wix create non advertised shortcut for all users / per machine

    - by mcdon
    In WIX, how do you create a non advertised shortcut in the allusers profile? So far I've only been able to accomplish this with advertised shortcuts. I prefer advertised shortcuts because you can go to the shortcut's properties and use "find target". In the tutorials I've seen use a registry value for the keypath of a shortcut. The problem is they use HKCU as the root. When HKCU is used, and another user uninstalls the program (since it's installed for all users) the registry key is left behind. When I use HKMU as the root I get an ICE57 error, but the key is removed when another user uninstalls the program. I seem to be pushed towards using HKCU though HKMU seems to behave correctly (per-user vs all-users). When I try to create the non advertised shortcut I get various ICE error such as ICE38, ICE43, or ICE 57. Most articles I've seen recommend "just ignore the ice errors". There must be a way to create the non advertised shortcuts, without creating ICE errors. Please post sample code for a working example.

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  • Non-Relational Database Design

    - by Ian Varley
    I'm interested in hearing about design strategies you have used with non-relational "nosql" databases - that is, the (mostly new) class of data stores that don't use traditional relational design or SQL (such as Hypertable, CouchDB, SimpleDB, Google App Engine datastore, Voldemort, Cassandra, SQL Data Services, etc.). They're also often referred to as "key/value stores", and at base they act like giant distributed persistent hash tables. Specifically, I want to learn about the differences in conceptual data design with these new databases. What's easier, what's harder, what can't be done at all? Have you come up with alternate designs that work much better in the non-relational world? Have you hit your head against anything that seems impossible? Have you bridged the gap with any design patterns, e.g. to translate from one to the other? Do you even do explicit data models at all now (e.g. in UML) or have you chucked them entirely in favor of semi-structured / document-oriented data blobs? Do you miss any of the major extra services that RDBMSes provide, like relational integrity, arbitrarily complex transaction support, triggers, etc? I come from a SQL relational DB background, so normalization is in my blood. That said, I get the advantages of non-relational databases for simplicity and scaling, and my gut tells me that there has to be a richer overlap of design capabilities. What have you done? FYI, there have been StackOverflow discussions on similar topics here: the next generation of databases changing schemas to work with Google App Engine choosing a document-oriented database

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  • Sanitize a string with non-alphanum repetition

    - by Toto
    I need to sanitize article titles when (creative) users try to "attract attention" with some non-alphanum repetition. Exemples: Buy my product !!!!!!!!!!!!!!!!!!!!!!!! Buy my product !? !? !? !? !? !? Buy my product !!!!!!!!!.......!!!!!!!! Buy my product <----------- Some acceptable solution would be to reduce the repetition of non-alphanum to 2. So I would get: Buy my product !! Buy my product !? !? Buy my product !!..!! Buy my product <-- This solution did not work that well: preg_replace('/(\W{2,})(?=\1+)/', '', $title) Any idea how to do it in PHP with regex? Other better solution is also welcomed (I cannot strip all the non-alphanum characters as they can make sense). Edit: the objective is only to avoid most common issues. The other creative cases will be sanitized manually or sanitized with an other regex.

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  • Cooperative/Non-preemptive threading avoiding threadlooks?

    - by Wayne
    Any creative ideas to avoid deadlocks on a yield or sleep with cooperative/non-preemptive multitasking without doing an O/S Thread.Sleep(10)? Typically the yield or sleep call will call back into the scheduler to run other tasks. But this can sometime produce deadlocks. Some background: This application has enormous need for speed and, so far, it's extremely fast as compared to other systems in the same industry. One of the speed techniques is cooperative/non-preemptive threading rather then the cost of a context switch from O/S threads. The high level design a priority manager which calls out to tasks depending on priority and processing time. Each task does one "iteration" of work and returns to wait its turn again in the priority queue. The tricky thing with non-preemptive threading is what to do when you want to a particular task to stop in the middle of work and wait for some other event from a different task before continuing. In this case, we have 3 tasks, A B and C where A is a controller that must synchronize the activity of B and C. First, A starts both B and C. Then B yields so C gets invoked. When C yields, A sees they are both inactive, decides it's time for B to run but not time for C yet. Well B is now stuck in a yield that has called C, so it can never run. Sincerely, Wayne

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  • Deterministic and non uniform long string generation from seed

    - by Limonup
    I had this weird idea for an encryption that I wanted to try out, it may be bad, and it may have done before, but I'm just doing it for fun. The short version of the question is: Is it possible to generate a long, deterministic and non-uniformly distributed string/sequence of numbers from a small seed? Long(er) version: I was thinking to encrypt a text by changing encoding. The new encoding would be generated via Huffman algorithm. To work well, the Huffman algorithm would need a fairly long text with non uniform distribution. Then characters can have different bit-lengths which would be the primary strength of this encryption. The problem is that its impractical to enter in/remember a long text each time you want to decrypt the text. So I was wondering if it was possible to generate a text from password seed? It doesn't matter what the text is, as long as it has non uniform distribution of characters and that the exact same sequence can be recreated each time you give it the same seed. Preferably, are there any functions/extensions in Python that can do this? EDIT: To expand on the "strength" of varying bit length: if I have a string "test", ASCII values 116, 101, 115, 116, which gives bit values of 1110100 1100101 1110011 1110100 Then, say my Huffman algorithm generates encoding like t = 101 e = 1100111 s = 10001 The final string is 101 1100111 10001 101, if we encode this back to ASCII, we get 1011100 1111000 1101000, which is 3 entirely different characters. Obviously its impossible to perform any kind of frequency analysis or something like that on this.

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  • XSLT: Transforming into non-xml content?

    - by Ian Boyd
    Is it possible to use XSLT to transform XML into something other than XML? e.g. i want the final non-xml content: <HTML> <BODY> <IMG src="file1.png"><BR> <IMG src="file2.png"><BR> ... <IMG src="filen.png"><BR> </BODY> </HTML> You'll notice this document is HTML, because in HTML IMG and BR tags are forbidden from having a closing tag. This constrasts with xhtml, the reformulation of HTML using xml, where all elements are required from having a closing tag (because in xml every tag must be closed). Is it possible, using XSLT, to generate non-xml output? Another example of non-xml output might be: INSERT INTO Documents (Filename) VALUES ('file1.png') INSERT INTO Documents (Filename) VALUES ('file2.png') ... INSERT INTO Documents (Filename) VALUES ('file3.png') The reason i ask is that as soon as my XSLT contains an <IMG>, the stylesheet contains an error; no closing </IMG>.

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  • OnConnect event not firing when using TClientSocket inside a TThread on non-blocking mode

    - by mathematician1975
    I am trying to make use of Borlands TClientSocket component in non-blocking mode inside a multithreaded C++ Windows application. I am creating multiple threads (classes derived from TThread), each of which creates its own TClientSocket object. I then assign member functions of the thread class to act as event handlers for the OnConnect, OnDisconnect and OnSocketError events of the socket. The problem I am having here is that whenever I call the TClientSocket::Open() function from within the TThread::Execute() function, the OnConnect event never fires. However, When I call the Open() function from the VCL thread prior to the TThread::Execute() function getting called, all of the events fire and I can use the thread-socket combination as I would like. Now I have not read anything in documentation that says that TClientSocket should not be used in non-blocking mode when used inside a thread, but it appears to me that there is perhaps something wrong conceptually in the way I am trying to use this class. Borland documentation is quite poor on the subject and these components have now been deprecated so reliable information is hard to come by. Despite being deprecated I have to use them as there is no alternative in the Builder 6 package I have. Can anyone please advise me if there is a right/wrong way to use TThread and a non-blocking TClientSocket in combination. I have never had problems using it as part of the VCL thread and never had problems using TServerSocket before and I really cannot understand why some events are not firing.

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  • C++: calling non-member functions with the same syntax of member ones

    - by peoro
    One thing I'd like to do in C++ is to call non-member functions with the same syntax you call member functions: class A { }; void f( A & this ) { /* ... */ } // ... A a; a.f(); // this is the same as f(a); Of course this could only work as long as f is not virtual (since it cannot appear in A's virtual table. f doesn't need to access A's non-public members. f doesn't conflict with a function declared in A (A::f). I'd like such a syntax because in my opinion it would be quite comfortable and would push good habits: calling str.strip() on a std::string (where strip is a function defined by the user) would sound a lot better than calling strip( str );. most of the times (always?) classes provide some member functions which don't require to be member (ie: are not virtual and don't use non-public members). This breaks encapsulation, but is the most practical thing to do (due to point 1). My question here is: what do you think of such feature? Do you think it would be something nice, or something that would introduce more issues than the ones it aims to solve? Could it make sense to propose such a feature to the next standard (the one after C++0x)? Of course this is just a brief description of this idea; it is not complete; we'd probably need to explicitly mark a function with a special keyword to let it work like this and many other stuff.

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  • Use of 'super' keyword when accessing non-overridden superclass methods

    - by jonny
    I'm trying to get the hang of inheritance in Java and have learnt that when overriding methods (and hiding fields) in sub classes, they can still be accessed from the super class by using the 'super' keyword. What I want to know is, should the 'super' keyword be used for non-overridden methods? Is there any difference (for non-overridden methods / non-hidden fields)? I've put together an example below. public class Vehicle { public int tyreCost; public Vehicle(int tyreCost) { this.tyreCost = tyreCost; } public int getTyreCost() { return tyreCost; } } and public class Car extends Vehicle { public int wheelCount; public Vehicle(int tyreCost, int wheelCount) { super(tyreCost); this.wheelCount = wheelCount; } public int getTotalTyreReplacementCost() { return getTyreCost() * wheelCount; } } Specifically, given that getTyreCost() hasn't been overridden, should getTotalTyreReplacementCost() use getTyreCost(), or super.getTyreCost() ? I'm wondering whether super should be used in all instances where fields or methods of the superclass are accessed (to show in the code that you are accessing the superclass), or only in the overridden/hidden ones (so they stand out).

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  • Static Vs Non-Static Method Performance C#

    - by dotnetguts
    Hello All, I have few global methods declared in public class in my asp.net web application. I have habbit of declaring all global methods in public class in following format public static string MethodName(parameters) { } I want to know how it would impact on performance point of view? 1) Which one is Better? Static Method or Non-Static Method? 2) Reason why it is better? Following link shows Non-Static methods are good because, static methods are using locks to be Thread-safe. The always do internally a Monitor.Enter() and Monitor.exit() to ensure Thread-safety. http://bytes.com/topic/c-sharp/answers/231701-static-vs-non-static-function-performance And Following link shows Static Methods are good static methods are normally faster to invoke on the call stack than instance methods. There are several reasons for this in the C# programming language. Instance methods actually use the 'this' instance pointer as the first parameter, so an instance method will always have that overhead. Instance methods are also implemented with the callvirt instruction in the intermediate language, which imposes a slight overhead. Please note that changing your methods to static methods is unlikely to help much on ambitious performance goals, but it can help a tiny bit and possibly lead to further reductions. http://dotnetperls.com/static-method I am little confuse which one to use? Thanks

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  • Regarding C Static/Non Static Float Arrays (Xcode, Objective C)

    - by user1875290
    Basically I have a class method that returns a float array. If I return a static array I have the problem of it being too large or possibly even too small depending on the input parameter as the size of the array needed depends on the input size. If I return just a float array[arraysize] I have the size problem solved but I have other problems. Say for example I address each element of the non-static float array individually e.g. NSLog(@"array[0] %f array[1] %f array[2] %f",array[0],array[1],array[2]); It prints the correct values for the array. However if I instead use a loop e.g. for (int i = 0; i < 3; i++) { NSLog(@"array[%i] %f",i,array[i]); } I get some very strange numbers (apart from the last index, oddly). Why do these two things produce different results? I'm aware that its bad practice to simply return a non static float, but even so, these two means of addressing the array look the same to me. Relevant code from class method (for non-static version)... float array[arraysize]; //many lines of code later if (weShouldStoreValue == true) { array[index] = theFloat; index = index + 1; } //more lines of code later return array; Note that it returns a (float*).

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  • What is the rationale to not allow overloading of C++ conversions operator with non-member function

    - by Vicente Botet Escriba
    C++0x has added explicit conversion operators, but they must always be defined as members of the Source class. The same applies to the assignment operator, it must be defined on the Target class. When the Source and Target classes of the needed conversion are independent of each other, neither the Source can define a conversion operator, neither the Target can define a constructor from a Source. Usually we get it by defining a specific function such as Target ConvertToTarget(Source& v); If C++0x allowed to overload conversion operator by non member functions we could for example define the conversion implicitly or explicitly between unrelated types. template < typename To, typename From > operator To(const From& val); For example we could specialize the conversion from chrono::time_point to posix_time::ptime as follows template < class Clock, class Duration> operator boost::posix_time::ptime( const boost::chrono::time_point<Clock, Duration>& from) { using namespace boost; typedef chrono::time_point<Clock, Duration> time_point_t; typedef chrono::nanoseconds duration_t; typedef duration_t::rep rep_t; rep_t d = chrono::duration_cast<duration_t>( from.time_since_epoch()).count(); rep_t sec = d/1000000000; rep_t nsec = d%1000000000; return posix_time::from_time_t(0)+ posix_time::seconds(static_cast<long>(sec))+ posix_time::nanoseconds(nsec); } And use the conversion as any other conversion. For a more complete description of the problem, see here or on my Boost.Conversion library.. So the question is: What is the rationale to non allow overloading of C++ conversions operator with non-member functions?

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  • Will TFS 2010 support non-contiguous merging?

    - by steve_d
    I know that merging non-contiguous changesets at once may not be a good idea. However there is at least one situation in which merging non-contiguous changesets is (probably) not going to break anything: when there are no intervening changes on the affected individual files. (At least, it wouldn't break any worse than would a series of cherry-picked merges, checked in each time; and at least this way you would discover breakage before checking in). For instance, let's say you have a Main and a Development branch. They start out identical (e.g. after a release). They have two files, foo.cs and bar.cs. Alice makes a change in Development\foo.cs and checks it in as changeset #1001. Bob makes a change in Development\bar.cs and checks it in as #1002. Alice makes another change to Development\foo.cs and checks it in as #1003. Now we could in theory merge both changes #1001 and #1003 from dev-to main in a single operation. If we try to merge at the branch level, dev-to-main, we will have to do it as two operations. In this simple, contrived example it's simple enough to merge the one file - but in the real world where there would be many files involved, it's not so simple. Non-contiguous merging is one of the reasons given for why "merge by workitem" is not implemented in TFS.

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  • Paypal Sandbox 2014 Non US test account Sign Up proper link

    - by Flood Gravemind
    Ok I had a Paypal Sandbox account a year ago. I am developing a new site for a client and when I try to Login it won't recognize my email address. I tried forgot my password forgot password still nothing. So I guessed that maybe due to inactivity for such a long time they may have deleted my account. So then I try to Sign Up for a new one. I entered my details 3 times now and spent 6 hours trying to figure out what is the proper link to do this. Then I went to another Sandbox link which required me to entered a US Zip code and its a dead end. I am not even sure which Paypal account I signed up for those three times. No email nothing at all. I am a Non US developer and the FAQ link for Non US developers just points to their REST API. Can someone please guide me to the proper Paypal Sandbox Setup for Non US developers including the proper sign up links please. And I know Stackoverflow does not like rants but from my experience dealing with Paypal, GTA 6 should make a satirical Paypal company in their next Game with Paypal Developer Rampage mode for the main protagonist who also happens to be a Developer. EDIT: REST API does not include UK :(

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  • Detect Unicode Usage in SQL Column

    One optimization you can make to a SQL table that is overly large is to change from nvarchar (or nchar) to varchar (or char).  Doing so will cut the size used by the data in half, from 2 bytes per character (+ 2 bytes of overhead for varchar) to only 1 byte per character.  However, you will lose the ability to store Unicode characters, such as those used by many non-English alphabets.  If the tables are storing user-input, and your application is or might one day be used internationally, its likely that using Unicode for your characters is a good thing.  However, if instead the data is being generated by your application itself or your development team (such as lookup data), and you can be certain that Unicode character sets are not required, then switching such columns to varchar/char can be an easy improvement to make. Avoid Premature Optimization If you are working with a lookup table that has a small number of rows, and is only ever referenced in the application by its numeric ID column, then you wont see any benefit to using varchar vs. nvarchar.  More generally, for small tables, you wont see any significant benefit.  Thus, if you have a general policy in place to use nvarchar/nchar because it offers more flexibility, do not take this post as a recommendation to go against this policy anywhere you can.  You really only want to act on measurable evidence that suggests that using Unicode is resulting in a problem, and that you wont lose anything by switching to varchar/char. Obviously the main reason to make this change is to reduce the amount of space required by each row.  This in turn affects how many rows SQL Server can page through at a time, and can also impact index size and how much disk I/O is required to respond to queries, etc.  If for example you have a table with 100 million records in it and this table has a column of type nchar(5), this column will use 5 * 2 = 10 bytes per row, and with 100M rows that works out to 10 bytes * 100 million = 1000 MBytes or 1GB.  If it turns out that this column only ever stores ASCII characters, then changing it to char(5) would reduce this to 5*1 = 5 bytes per row, and only 500MB.  Of course, if it turns out that it only ever stores the values true and false then you could go further and replace it with a bit data type which uses only 1 byte per row (100MB  total). Detecting Whether Unicode Is In Use So by now you think that you have a problem and that it might be alleviated by switching some columns from nvarchar/nchar to varchar/char but youre not sure whether youre currently using Unicode in these columns.  By definition, you should only be thinking about this for a column that has a lot of rows in it, since the benefits just arent there for a small table, so you cant just eyeball it and look for any non-ASCII characters.  Instead, you need a query.  Its actually very simple: SELECT DISTINCT(CategoryName)FROM CategoriesWHERE CategoryName <> CONVERT(varchar, CategoryName) Summary Gregg Stark for the tip. Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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  • VSDBCMD returns "An unexpected failure occurred: Object reference not set to an instance of an objec

    - by Matt Wrock
    I have been succesfully using the command line database deployment tool VSDBCMD on my dev and test environments but the tool fails in our integration environmrnt. I am using the VS 2010 version of the tool. The servers have all of the prerequisites including: .net 4.0 sql server compact edition 3.5 sp1 (as well as the full edition of 2008) sql server 2008 server management objects sql server 2008 native client sql server system clr types msxml 6 all of the dependent DLLs included in: C:\Program Files\Microsoft SQL Server Compact Edition\v3.5\desktop*.dll C:\Program Files\Microsoft SQL Server Compact Edition\v3.5*.dll C:\Program Files (x86)\Microsoft Visual Studio 10.0\VSTSDB\Deploy**. The only reference to this error that I have been able to find has to do with a bug in the VS 2008 edition when the HKEY_CURRENT_USER\Software\Microsoft\VisualStudio\9.0 key is missing. In my case the 10.0 version of the key exists. Has anyone else encountered this?

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  • Is there an extensible SQL like query language that is safe for exposing via a public API?

    - by Lokkju
    I want to expose some spatial (and a few non-spatial) datasets via a public API. The backend store will either be PostgreSQL/PostGIS, sqlite/spatialite, or CouchDB/GeoCouch. My goal is to find a some, preferably standard, way to allow people to make complex spatial queries against the data. I would like it to be a simple GET based request. The idea is to allow safe SQL type queries, without allowing unsafe ones. I would rather modify something that is off the shelf than doing the entire thing myself. I specifically want to support requesting specific fields from a table; joining results; and spatial functions that are already implemented by the underlying datastore. Ideas anyone?

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  • Cross-database transactions from one SP

    - by Michael Bray
    I need to update multiple databases with a few simple SQL statement. The databases are configurared in SQL using 'Linked Servers', and the SQL versions are mixed (SQL 2008, SQL 2005, and SQL 2000). I intend to write a stored procedure in one of the databases, but I would like to do so using a transaction to make sure that each database gets updated consistently. Which of the following is the most accurate: Will a single BEGIN/COMMIT TRANSACTION work to guarantee that all statements across all databases are successful? Will I need multiple BEGIN TRANSACTIONS for each individual set of commands on a database? Are transactions even supported when updating remote databases? I would need to execute a remote SP with embedded transaction support. Note that I don't care about any kind of cross-database referential integrity; I'm just trying to update multiple databases at the same time from a single stored procedure if possible. Any other suggestions are welcome as well. Thanks!

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  • Question about DBD::CSB Statement-Functions

    - by sid_com
    From the SQL::Statement::Functions documentation: Function syntax When using SQL::Statement/SQL::Parser directly to parse SQL, functions (either built-in or user-defined) may occur anywhere in a SQL statement that values, column names, table names, or predicates may occur. When using the modules through a DBD or in any other context in which the SQL is both parsed and executed, functions can occur in the same places except that they can not occur in the column selection clause of a SELECT statement that contains a FROM clause. # valid for both parsing and executing SELECT MyFunc(args); SELECT * FROM MyFunc(args); SELECT * FROM x WHERE MyFuncs(args); SELECT * FROM x WHERE y < MyFuncs(args); # valid only for parsing (won't work from a DBD) SELECT MyFunc(args) FROM x WHERE y; Reading this I would expect that the first SELECT-statement of my example shouldn't work and the second should but it is quite the contrary. #!/usr/bin/env perl use warnings; use strict; use 5.010; use DBI; open my $fh, '>', 'test.csv' or die $!; say $fh "id,name"; say $fh "1,Brown"; say $fh "2,Smith"; say $fh "7,Smith"; say $fh "8,Green"; close $fh; my $dbh = DBI->connect ( 'dbi:CSV:', undef, undef, { RaiseError => 1, f_ext => '.csv', }); my $table = 'test'; say "\nSELECT 1"; my $sth = $dbh->prepare ( "SELECT MAX( id ) FROM $table WHERE name LIKE 'Smith'" ); $sth->execute (); $sth->dump_results(); say "\nSELECT 2"; $sth = $dbh->prepare ( "SELECT * FROM $table WHERE id = MAX( id )" ); $sth->execute (); $sth->dump_results(); outputs: SELECT 1 '7' 1 rows SELECT 2 Unknown function 'MAX' at /usr/lib/perl5/site_perl/5.10.0/SQL/Parser.pm line 2893. DBD::CSV::db prepare failed: Unknown function 'MAX' at /usr/lib/perl5/site_perl/5.10.0/SQL/Parser.pm line 2894. [for Statement "SELECT * FROM test WHERE id = MAX( id )"] at ./so_3.pl line 30. DBD::CSV::db prepare failed: Unknown function 'MAX' at /usr/lib/perl5/site_perl/5.10.0/SQL/Parser.pm line 2894. [for Statement "SELECT * FROM test WHERE id = MAX( id )"] at ./so_3.pl line 30. Could someone explaine me this behavior?

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  • How can I copy from the browser and paste to vim without unicode problems

    - by dsummersl
    This happens to me all the time: I copy something from a rich text screen (usually a browser) and then paste it into vim. Usually its a code block and then when I go to compile or run or what have you I get all kind of bazaar errors. I scratch my head, and then spend half an hour trying to figure out what is wrong before I realize I've copied some non ASCII characters: dashes, left and right quotes, long underscores, multiplication signs in place of x's, etc. So I ask you: how can I copy non-ASCII into my VIM session without error? Is there a paste mode that automatically 'down samples' unicode to ASCII? Is there a quick/dirty search for non ASCII characters in a file?

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  • How to get result size from an SQL query and check size

    - by Jimmy
    Hi I'm trying to write a piece of code for a simple verification method as part of a MVC. At present the SQL is not written as a prepared statement so obviously it is at risk to a SQL injection so any help in regards to writing the SQL as a prepared statement would be really helpful. The method which is in the User model. public boolean getLoginInfo() { try { DBAccess dbAccess = new DBAccess(); String sql = "SELECT username, password FROM owner WHERE username = '" + this.username + "'AND password = '" + this.password + "';"; dbAccess.close();dbAccess.executeQuery(sql); dbAccess.close(); return true; } catch (Exception e) { return false; } } I want to get the size of the result set which is generated by the SQL query and if the size of it is 1 return true else it's false. If you need more info on the rest of the MVC just post and I'll get it up here.

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