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• How to group data changes by operation with MySQL triggers

  - by Jan-Henk

  I am using triggers in MySQL to log changes to the data. These changes are recorded on a row level. I can now insert an entry in my log table for each row that is changed. However, I also need to record the operation to which the changes belong. For example, a delete operation like "DELETE * FROM table WHERE type=x" can delete multiple rows. With the trigger I can insert an entry for each deleted row into the log table, but I would like to also provide a unique identifier for the operation as a whole, so that the log table looks something like: log_id operation_id tablename fieldname oldvalue newvalue 1 1 table id 1 null 2 1 table type a null 3 1 table id 2 null 4 1 table type a null 5 2 table id 3 null 6 2 table type b null 7 2 table id 4 null 8 2 table type b null Is there a way in MySQL to identify the higher level operation to which the row changes belong? Or is this only possible by means of application level code? In the future it would also be nice to be able to record the transaction to which an operation belongs. Another question is if it is possible to capture the actual SQL query, besides using the query log. I don't think so myself, but maybe I am missing something. It is of course possible to capture these at the application level, but the goal is to keep intrusions to the application level code as minimal as possible. When this is not possible with MySQL, how is this with other database systems? For the current project it is not an option to use something other than MySQL, but it would be nice to know for future projects.

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• How can I filter these Django records?

  - by mipadi

  I have a set of Django models as shown in the following diagram (the names of the reverse relationships are shown in the yellow bubbles): In each relationship, a Person may have 0 or more of the items. Additionally, the slug field is (unfortunately) not unique; multiple Person records may have the same slug fields. Essentially these records are duplicates. I want to obtain a list of all records that meet the following criteria: All duplicate records (that is, having the same slug) with at least one Entry OR at least one Audio OR at least one Episode OR at least one Article. So far, I have the following query: Person.objects.values('slug').annotate(num_records=Count('slug')).filter(num_records__gt=1) This groups all records by slug, then adds a num_records attribute that says how many records have that slug, but the additional filtering is not performed (and I don't even know if this would work right anyway, since, given a set of duplicate records, one may have, e.g., and Entry and the other may have an Article). In a nutshell, I want to find all duplicate records and collapse them, along with their associated models, into one record. What's the best way to do this with Django?

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• How do you go about finding out whether an idea you've had has already been patented?

  - by Iain Fraser

  I have an idea for image copy-protection that I'm in the process of coding up and plan on selling to one of my clients who sells images online. If successful I think there would be a lot of people in a similar situation to my client who would be interested in the code also. I think this is a fairly unique idea that could be packaged into a saleable product - but if I did do this, I wouldn't want some big corporation decending on me with their lawyers after all my hard work. So before I put too much work into this I'd really like to know how I'd go about finding if this idea has been patented already and whether I'd get in trouble if I sold my product and if it would be worthwhile patenting the idea myself. Although I find the idea of software patenting abhorrent, it would be more to protect myself from the usual suspects than to stop fellow-developers from using the idea (if it is in fact a worthwhile one). I live in Australia, so an idea of who to go and see and a ball park figure of how much money I'd be looking at having to pay would be fantastic (in orders of a magnitude: 100s, 1000s, 10s of thousands of dollars, etc). Cheers Iain

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• Delphi Application using COMMIT and ROLLBACK for Multiple SQL Updates

  - by Matt

  Is it possible to use the SQL BEGIN TRANSACTION, COMMIT TRANSACTION, ROLLBACK TRANSACTION when embedding SQL Queries into an application with mutiple calls to the SQL for Table Updates. For example I have the following code: Q.SQL.ADD(<UPDATE A RECORD>); Q.ExecSQL; Q.Close; Q.SQL.Clear; Q.SQL.ADD(<Select Some Data>); Q.Open; Set Some Variables Q.Close; Q.SQL.Clear; Q.SQL.ADD(<UPDATE A RECORD>); Q.ExecSQL; What I would like to do is if the second update fails I want to roll back the first transaction. If I set a unique notation for the BEGIN, COMMIT, ROLLBACK so as to specify what is being committed or rolled back, is it feasible. i.e. before the first Update specify BEGIN TRANSACTION_A then after the last update specify COMMIT TRANSACTION_A I hope that makes sense. If I was doing this in a SQL Stored Procedure then I would be able to specify this at the start and end of the procedure, but I have had to break the code down into manageable chunks due to process blocks and deadlocks on a heavy loaded SQL Server.

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• Delphi, PGDac vs Zeos, Fetch, Lookup?

  - by durumdara

  Hi! I used Zeos to test to know: is ZTable uses fetch technics, or not? May in the future we migrate our lesser system to PGSQL, and this used now "Table" components (as BDE, but it have an SQL-like server). These tables use real cursors, a "Window" with N record, so lookup is very fast, because the Locate/Lookup is started on server, and only these N records are refreshed, no matter, how many records in the lookup table. PGSQL uses fetch technics as I know, and I tested it with a table (id int, name varchar(100)), and 1 million records. (I also trying this with mysql). The adapter is Zeos. ID, sec to find, allocated memory in bytes on client. MySQL 500000 2,761 113 196 344 1000000 3,214 225 471 232 313800 0,437 225 471 232 328066 0,468 225 471 232 276374 0,390 225 471 232 905984 1,264 225 471 232 260253 0,359 225 471 232 PGSQL 500000 3,042 113 188 184 1000000 3,744 225 463 064 313800 0,436 225 463 064 328066 0,452 225 463 064 276374 0,375 225 463 064 905984 1,295 225 463 064 260253 0,359 225 463 064 142023 0,203 225 463 064 As you see the records are fetched locally, this cause the 225 MB usage, and searches are slow a little, based where is the record we must find. I want to ask more things: a.) Is PGDAC have some technics to we can use the lookups without pay the fetch with memory and secs? b.) Or is PG ODBC driver can help in this problem with ADO? (As I know ADO can use server side cursors)? c.) Have anybody some experience with lookup tables, and performance? Is this critical question or it is not? (With client memory usage too). d.) If no chance to avoid fetch hell with lookups, what we can do? Server Side Joins, and unique code for Lookup field changing without real Lookup? Thanks for your help: dd

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• Random String Generator creates same string on multiple calls

  - by rockinthesixstring

  Hi there. I've build a random string generator but I'm having a problem whereby if I call the function multiple times say in a Page_Load method, the function returns the same string twice. here's the code ''' <summary>' ''' Generates a Random String' ''' </summary>' ''' <param name="n">number of characters the method should generate</param>' ''' <param name="UseSpecial">should the method include special characters? IE: # ,$, !, etc.</param>' ''' <param name="SpecialOnly">should the method include only the special characters and excludes alpha numeric</param>' ''' <returns>a random string n characters long</returns>' Public Function GenerateRandom(ByVal n As Integer, Optional ByVal UseSpecial As Boolean = True, Optional ByVal SpecialOnly As Boolean = False) As String Dim chars As String() ' a character array to use when generating a random string' Dim ichars As Integer = 74 'number of characters to use out of the chars string' Dim schars As Integer = 0 ' number of characters to skip out of the characters string' chars = { _ "A", "B", "C", "D", "E", "F", _ "G", "H", "I", "J", "K", "L", _ "M", "N", "O", "P", "Q", "R", _ "S", "T", "U", "V", "W", "X", _ "Y", "Z", "0", "1", "2", "3", _ "4", "5", "6", "7", "8", "9", _ "a", "b", "c", "d", "e", "f", _ "g", "h", "i", "j", "k", "l", _ "m", "n", "o", "p", "q", "r", _ "s", "t", "u", "v", "w", "x", _ "y", "z", "!", "@", "#", "$", _ "%", "^", "&", "*", "(", ")", _ "-", "+"} If Not UseSpecial Then ichars = 62 ' only use the alpha numeric characters out of "char"' If SpecialOnly Then schars = 62 : ichars = 74 ' skip the alpha numeric characters out of "char"' Dim rnd As New Random() Dim random As String = String.Empty Dim i As Integer = 0 While i < n random += chars(rnd.[Next](schars, ichars)) System.Math.Max(System.Threading.Interlocked.Increment(i), i - 1) End While rnd = Nothing Return random End Function but if I call something like this Dim str1 As String = GenerateRandom(5) Dim str2 As String = GenerateRandom(5) the response will be something like this g*3Jq g*3Jq and the second time I call it, it will be 3QM0$ 3QM0$ What am I missing? I'd like every random string to be generated as unique.

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• Database Design Question regaurding duplicate information.

  - by galford13x

  I have a database that contains a history of product sales. For example the following table CREATE TABLE SalesHistoryTable ( OrderID, // Order Number Unique to all orders ProductID, // Product ID can be used as a Key to look up product info in another table Price, // Price of the product per unit at the time of the order Quantity, // quantity of the product for the order Total, // total cost of the order for the product. (Price * Quantity) Date, // Date of the order StoreID, // The store that created the Order PRIMARY KEY(OrderID)); The table will eventually have millions of transactions. From this, profiles can be created for products in different geographical regions (based on the StoreID). Creating these profiles can be very time consuming as a database query. For example. SELECT ProductID, StoreID, SUM(Total) AS Total, SUM(Quantity) QTY, SUM(Total)/SUM(Quantity) AS AvgPrice FROM SalesHistoryTable GROUP BY ProductID, StoreID; The above query could be used to get the Information based on products for any particular store. You could then determine which store has sold the most, has made the most money, and on average sells for the most/least. This would be very costly to use as a normal query run anytime. What are some design descisions in order to allow these types of queries to run faster assuming storage size isn’t an issue. For example, I could create another Table with duplicate information. Store ID (Key), Product ID, TotalCost, QTY, AvgPrice And provide a trigger so that when a new order is received, the entry for that store is updated in a new table. The cost for the update is almost nothing. What should be considered when given the above scenario?

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• Do programmers need a union?

  - by James A. Rosen

  In light of the acrid responses to the intellectual property clause discussed in my previous question, I have to ask: why don't we have a programmers' union? There are many issues we face as employees, and we have very little ability to organize and negotiate. Could we band together with the writers', directors', or musicians' guilds, or are our needs unique? Has anyone ever tried to start one? If so, why did it fail? (Or, alternatively, why have I never heard of it, despite its success?) later: Keith has my idea basically right. I would also imagine the union being involved in many other topics, including: legal liability for others' use/misuse of our work, especially unintended uses evaluating the quality of computer science and software engineering higher education programs -- unlike many other engineering disciplines, we are not required to be certified on receiving our Bachelor's degrees evangelism and outreach -- especially to elementary school students certification -- not doing it, but working with the companies like ISC(2) and others to make certifications meaningful and useful continuing education -- similar to previous conferences -- maintain a go-to list of organizers and other resources our members can use I would see it less so as a traditional trade union, with little emphasis on: pay -- we tend to command fairly good salaries outsourcing and free trade -- most of use tend to be pretty free-market oriented working conditions -- we're the only industry with Aeron chairs being considered anything like "standard"

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• Quering container with Linq + group by ?

  - by Prix

  public class ItemList { public int GuID { get; set; } public int ItemID { get; set; } public string Name { get; set; } public entityType Status { get; set; } public class Waypoint { public int Zone { get; set; } public int SubID { get; set; } public int Heading { get; set; } public float PosX { get; set; } public float PosY { get; set; } public float PosZ { get; set; } } public List<Waypoint> Routes = new List<Waypoint>(); } I have a list of items using the above class and now I need to group it by ItemID and join the first entry of Routes of each iqual ItemID. So for example, let's say on my list I have: GUID ItemID ListOfRoutes 1 23 first entry only 2 23 first entry only 3 23 first entry only 4 23 first entry only 5 23 first entry only 6 23 first entry only 7 23 first entry only Means I have to group entries 1 to 7 as 1 Item with all the Routes entries. So I would have one ItemID 23 with 7 Routes on it where those routes are the first element of that given GUID Routes List. My question is if it is possible using LINQ to make a statment to do something like that this: var query = from ItemList entry in myList where status.Contains(entry.Status) group entry by entry.ItemID into result select new { items = new { ID = entry.ItemID, Name = entry.Name }, routes = from ItemList m in entry group m.Routes.FirstOrDefault() by n.NpcID into m2 }; So basicly I would have list of unique IDS information with a inner list of all the first entry of each GUID route that had the same ItemID.

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• How to insert an Array/Objet into SQL (bestpractice)

  - by Jason

  I need to store three items as an array in a single column and be able to quickly/easily modify that data in later functions. [---YOU CAN SKIP THIS PART IF YOU TRUST ME--] To be clear, I love and use x_ref tables all the time but an x_ref doesn't work here because this is not a one-to-many relationship. I am making a project management tool that among other things, assigns a user to a project and assigns hours to that project on a weekly basis, per user, sometimes for weeks many weeks into the future. Of course there are many projects, a project can have many team members, a team member can be involved with many projects at one time BUT its not one-to-many because a team member can be working many weeks on the same project but have different hours for different weeks. In other words, each object really is unique. Also/finally, this data can be changed at any time by any team-member - hence it needs to be easily to manipulate. Basically, I need to handle three values (the team member, the week we're talking about, and how many hours) dropped into a project row in the projects table (under the column for project team members) and treated as one item - a team member - that will actually be part of a larger array of all the team members involved on the project. [--END SKIP, START READING HERE :) --] So assuming that the application's general schema and relation tables aren't total crap and that we are in fact up against a wall in this one case to use an array/object as a value for this column, is there a best practice for that? Like a particular SQL data-type? A particular object/array format? CSV? JSON? XML? Most of the app is in C# but (for very odd reasons that I won't explain) we could really use any environment if there is a particular one that handles this well. For the moment, I am thinking either (webservice + JS/JSON) or PHP unserialize/serialize (but I am bit sketched out by the PHP solution because it seems a bit cumbersome when using ajax?) Thoughts anyone?

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• How to route tree-structured URLs with ASP.NET Routing?

  - by Venemo

  Hello Everyone, I would like to achieve something very similar to this question, with some enhancements. There is an ASP.NET MVC web application. I have a tree of entities. For example, a Page class which has a property called Children, which is of type IList<Page>. (An instance of the Page class corresponds to a row in a database.) I would like to assign a unique URL to every Page in the database. I handle Page objects with a Controller called PageController. Example URLs: http://mysite.com/Page1/ http://mysite.com/Page1/SubPage/ http://mysite.com/Page/ChildPage/GrandChildPage/ You get the picture. So, I'd like every single Page object to have its own URL that is equal to its parent's URL plus its own name. In addition to that, I also would like the ability to map a single Page to the / (root) URL. I would like to apply these rules: If a URL can be handled with any other route, or a file exists in the filesystem in the specified URL, let the default URL mapping happen If a URL can be handled by the virtual path provider, let that handle it If there is no other, map the other URLs to the PageController class I also found this question, and also this one and this one, but they weren't of much help, since they don't provide an explanation about my first two points. I see the following possible soutions: Map a route for each page invidually. This requires me to go over the entire tree when the application starts, and adding an exact match route to the end of the route table. I could add a route with {*path} and write a custom IRouteHandler that handles it, but I can't see how could I deal with the first two rules then, since this handler would get to handle everything. So far, the first solution seems to be the right one, because it is also the simplest. I would really appreciate your thoughts on this. Thank you in advance!

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• How to delete duplicate vectors within a multidimensional vector?

  - by David

  I have a vector of vectors: vector< vector<int> > BigVec; It contains an arbitrary number of vectors, each of an arbitrary size. I want to delete not duplicate elements of each vector, but any vectors that are the exact same as another. I don't need to preserve the order of the vectors so I can sort etc.. It should be a really simple problem to solve but I'm new to this, my (not-working) best effort: for (int i = 0; i < BigVec.size(); i++) { for (int j = 1; j < BigVec.size() ; j++ ) { if (BigVec[i][0] == BigVec [j][i]); { BigVec.erase(BigVec.begin() + j); i = 0; // because i get the impression deleting a j = 1; // vector messes up a simple iteration through } } } I think there might be a solution using Unique(), but I can't get that to work either.

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• SQL GUID Vs Integer

  - by Dal

  Hi I have recently started a new job and noticed that all the SQL tables use the GUID data type for the primary key. In my previous job we used integers (Auto-Increment) for the primary key and it was a lot more easier to work with in my opinion. For example, say you had two related tables; Product and ProductType - I could easily cross check the 'ProductTypeID' column of both tables for a particular row to quickly map the data in my head because its easy to store the number (2,4,45 etc) as opposed to (E75B92A3-3299-4407-A913-C5CA196B3CAB). The extra frustration comes from me wanting to understand how the tables are related, sadly there is no Database diagram :( A lot of people say that GUID's are better because you can define the unique identifer in your C# code for example using NewID() without requiring SQL SERVER to do it - this also allows you to know provisionally what the ID will be.... but I've seen that it is possible to still retrieve the 'next auto-incremented integer' too. A DBA contractor reported that our queries could be up to 30% faster if we used the Integer type instead of GUIDS... Why does the GUID data type exist, what advantages does it really provide?... Even if its a choice by some professional there must be some good reasons as to why its implemented?

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• What would be the time complexity of counting the number of all structurally different binary trees?

  - by ktslwy

  Using the method presented here: http://cslibrary.stanford.edu/110/BinaryTrees.html#java 12. countTrees() Solution (Java) /** For the key values 1...numKeys, how many structurally unique binary search trees are possible that store those keys? Strategy: consider that each value could be the root. Recursively find the size of the left and right subtrees. */ public static int countTrees(int numKeys) { if (numKeys <=1) { return(1); } else { // there will be one value at the root, with whatever remains // on the left and right each forming their own subtrees. // Iterate through all the values that could be the root... int sum = 0; int left, right, root; for (root=1; root<=numKeys; root++) { left = countTrees(root-1); right = countTrees(numKeys - root); // number of possible trees with this root == left*right sum += left*right; } return(sum); } } I have a sense that it might be n(n-1)(n-2)...1, i.e. n!

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• I am using relational division with EAV, but I need to find results in EAV that have some of the cat

  - by NewToDB

  I have two tables: CREATE TABLE EAV ( subscriber_id INT(1) NOT NULL DEFAULT '0', attribute_id CHAR(62) NOT NULL DEFAULT '', attribute_value CHAR(62) NOT NULL DEFAULT '', PRIMARY KEY (subscriber_id,attribute_id) ) INSERT INTO EAV (subscriber_id, attribute_id, attribute_value) VALUES (1,'color','red') INSERT INTO EAV (subscriber_id, attribute_id, attribute_value) VALUES (1,'size','xl') INSERT INTO EAV (subscriber_id, attribute_id, attribute_value) VALUES (1,'garment','shirt') INSERT INTO EAV (subscriber_id, attribute_id, attribute_value) VALUES (2,'color','red') INSERT INTO EAV (subscriber_id, attribute_id, attribute_value) VALUES (2,'size','xl') INSERT INTO EAV (subscriber_id, attribute_id, attribute_value) VALUES (2,'garment','pants') INSERT INTO EAV (subscriber_id, attribute_id, attribute_value) VALUES (3,'garment','pants') CREATE TABLE CRITERIA ( attribute_id CHAR(62) NOT NULL DEFAULT '', attribute_value CHAR(62) NOT NULL DEFAULT '' ) INSERT INTO CRITERIA (attribute_id, attribute_value) VALUES ('color', 'red') INSERT INTO CRITERIA (attribute_id, attribute_value) VALUES ('size', 'xl') To find all subscribers in the EAV that match my criteria, I use relational division: SELECT DISTINCT(subscriber_id) FROM EAV WHERE subscriber_id IN (SELECT E.subscriber_id FROM EAV AS E JOIN CRITERIA AS CR ON E.attribute_id = CR.attribute_id AND E.attribute_value = CR.attribute_value GROUP BY E.subscriber_id HAVING COUNT() = (SELECT COUNT() FROM CRITERIA)) This gives me an unique list of subscribers who have all the criteria. So that means I get back subscriber 1 and 2 since they are looking for the color red and size xl, and that's exactly my criteria. But what if I want to extend this so that I also get subscriber 3 since this subscriber didn't specifically say what color or size they want (ie. there is no entry for attribute 'color' or 'size' in the EAV table for subscriber 3). Given my current design, is there a way I can extend my query to include subscribers that have zero or more of the attributes defined, and if they do have the attribute defined, then it must match the criteria? Or is there a better way to design the table to aid in querying?

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• Combining data sets without losing observations in SAS

  - by John

  Hye guys, I know, another post another problem :D :(. I took a screenshot to easily explain my problem. http://i39.tinypic.com/rhms0h.jpg As you can see I want to merge two tables (again), the Base & Analyst table. What I want to achieve is displayed in the right bottom corner table. I’m calculating the number of total analysts and female analysts for each month in the analyst table. In the base table I have different observations for one company (here company Alcoa with ticker AA). When I use the following command: data want; merge base analyst; by month ; run; I get the right up corner problem. My observations in the main table are being narrowed down to only 4 observations (for each different year one observation, 2001, 2002, 2005, 2006). What I want is that the observations are not reduced but that for every year the same data is being placed as shown in the right bottom corner. What am I missing in my merge command? In both tables I have month as a time count variable ( the observations in my base table are monthly) on which I need to merge. For clarity I added 2 screenshots of my real databases in SAS. The base table: http://i42.tinypic.com/dr5jky.jpg The analyst table: http://i40.tinypic.com/eqpmqq.jpg Here is what my merged table looks like: http://i43.tinypic.com/116i62s.jpg You can clearly see that the merged table only has four observations left for AA (one for each unique year) instead of the original 8. Anyone an idea to solve this?

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• WPF : Multiple views, one DataContext

  - by zapho

  Hi, I'm working on a WPF application which must handle multiple screens (two at this this time). One view can be opened on several screens and user actions must be reflected consistently on all screens. To achieve this, for a given type of view, a single DataContext is instantiated. Then, when a view is displayed on a screen, the unique DataContext is attached to it. So, one DataContext, several views (same type of view/xaml). So far so good. It works quite well in most cases. I do have a problem with a specific view which relies on ItemsControl. These ItemsControl are used to display UIElements dynamically build in the ViewModel/DataContext (C# code). These UIElements are mostly Path objects. Example : <ItemsControl ItemsSource="{Binding WindVectors}"> <ItemsControl.Template> <ControlTemplate TargetType="{x:Type ItemsControl}"> <Canvas IsItemsHost="True" /> </ControlTemplate> </ItemsControl.Template> </ItemsControl> Here, WindVectors is a ObservableCollection<UIElement>. When the view is opened the first time, everything is fine. The problem is that when the view is opened one another screen, all ItemsControl are removed from the first screen and displayed one the second screen. Other WPF components (TextBlock for instance) on this view react normally and are displayed on both screens. Any help would be greatly appreciated. Thanks. Fabrice

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• Google App Engine - Uploading blobs and authentication

  - by Keyur

  (I tried asking this on the GAE forums but didn't get an answer so am trying it here.) Currently to upload blobs, the app engine's blob store service creates a unique one- time URL that a user can post blobs to. My requirement is that I only want authenticated / authorized users to post blobs in my application. I can achieve this currently if the page that includes the multipart form to upload blobs is in my application. However, I am looking to providing a "REST API" for my users to upload their blobs. While it is true that the one-time nature of the upload URL mitigates the chances of rogue use but it's still possible. I was wondering if there is anyone on the app engine team here that can consider a feature where developers can register an upload listener. (Or if there is already a way, I'll be all ears). A standard servlet filter could also potentially do the job. This will give us an opportunity to authenticate / validate / decorate requests before the request gets forwarded to the blob store service. Thanks, Keyur

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• Android 2.1 fling gesture captured on textview but still a contextmenu opens

  - by hermo

  The following problem seems unique to 2.1, happens both on an emulator and on a nexus. The same example works fine on other platforms I've tested (1.5, 1.6 and 2.0 emulators). I've added created gestureListener as described in this post. The difference is that I've added the listener on a TextView which also has a contextMenu registered, i.e. sth like the following: onCreate(...) { ... // Layout contains a large TextView on which I want to add a context menu tv = findViewById(R.id.text_view); tv.registerForContextMenu(this); // create the gestureListener according above mentioned post. gestureListener = ... // set the listener on the text-view tv.setOnTouchListener(gestureListener); ... } When testing it, the correct gesture is recognized alright, but every other time it also causes the context menu to be opened. As the same example is working on non 2.1 platforms, I've got a feeling it is not my code that is the problem... Thankful for any suggestions.

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• Slow retrieval of data in SQLITE takes a long using ContentProvider

  - by Arlyn

  I have an application in Android (running 4.0.3) that stores a lot of data in Table A. Table A resides in SQLite Database. I am using a ContentProvider as an abstraction layer above the database. Lots of data here means almost 80,000 records per month. Table A is structured like this: String SQL_CREATE_TABLE = "CREATE TABLE IF NOT EXISTS " + TABLE_A + " ( " + COLUMN_ID + " INTEGER PRIMARY KEY NOT NULL" + "," + COLUMN_GROUPNO + " INTEGER NOT NULL DEFAULT(0)" + "," + COLUMN_TIMESTAMP + " DATETIME UNIQUE NOT NULL" + "," + COLUMN_TAG + " TEXT" + "," + COLUMN_VALUE + " REAL NOT NULL" + "," + COLUMN_DEVICEID + " TEXT NOT NULL" + "," + COLUMN_NEW + " NUMERIC NOT NULL DEFAULT(1)" + " )"; Here is the index statement: String SQL_CREATE_INDEX_TIMESTAMP = "CREATE INDEX IF NOT EXISTS " + TABLE_A + "_" + COLUMN_TIMESTAMP + " ON " + TABLE_A + " (" + COLUMN_TIMESTAMP + ") "; I have defined the columns as well as the table name as String Constants. I am already experiencing significant slow down when retrieving this data from Table A. The problem is that when I retrieve data from this table, I first put it in an ArrayList and then I display it. Obviously, this is possibly the wrong way of doing things. I am trying to find a better way to approach this problem using a ContentProvider. But this is not the problem that bothers me. The problem is for some reason, it takes a lot longer to retrieve data from other tables which have only upto 12 records maximum. I see this delay increase as the number of records in Table A increase. This does not make any sense. I can understand the delay if I retrieve data from Table A, but why the delay in retrieving data from other tables. To clarify, I do not experience this delay if Table A is empty or has less than 3000 records. What could be the problem?

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• MySQL ORDER BY DESC is fast but ASC is very slow

  - by Pepper

  Hello, I'm completely stumped on this one. For some reason when I sort this query by DESC it's super fast, but if sorted by ASC it's extremely slow. This takes about 150 milliseconds: SELECT posts.id FROM posts USE INDEX (published) WHERE posts.feed_id IN ( 4953,622,1,1852,4952,76,623,624,10 ) ORDER BY posts.published DESC LIMIT 0, 50; This takes about 32 seconds: SELECT posts.id FROM posts USE INDEX (published) WHERE posts.feed_id IN ( 4953,622,1,1852,4952,76,623,624,10 ) ORDER BY posts.published ASC LIMIT 0, 50; The EXPLAIN is the same for both queries. id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE posts index NULL published 5 NULL 50 Using where I've tracked it down to "USE INDEX (published)". If I take that out it's the same performance both ways. But the EXPLAIN shows the query is less efficient overall. id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE posts range feed_id feed_id 4 \N 759 Using where; Using filesort And here's the table. CREATE TABLE `posts` ( `id` int(20) NOT NULL AUTO_INCREMENT, `feed_id` int(11) NOT NULL, `post_url` varchar(255) NOT NULL, `title` varchar(255) NOT NULL, `content` blob, `author` varchar(255) DEFAULT NULL, `published` int(12) DEFAULT NULL, `updated` datetime NOT NULL, `created` datetime NOT NULL, PRIMARY KEY (`id`), UNIQUE KEY `post_url` (`post_url`,`feed_id`), KEY `feed_id` (`feed_id`), KEY `published` (`published`) ) ENGINE=InnoDB AUTO_INCREMENT=196530 DEFAULT CHARSET=latin1; Is there a fix for this? Thanks!

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• Creating form using Generic_inlineformset_factory from the Model Form

  - by Prateek

  hello dear all, I wanted to create a edit form with the help of ModelForm. and my models contain a Generic relation b/w classes, so if any one could suggest me the view and a bit of template for the purpose I would be very thankful, as I am new to the language. My models look like:- class Employee(Person): nickname = models.CharField(_('nickname'), max_length=25, null=True, blank=True) blood_type = models.CharField(_('blood group'), max_length=3, null=True, blank=True, choices=BLOOD_TYPE_CHOICES) marital_status = models.CharField(_('marital status'), max_length=1, null=True, blank=True, choices=MARITAL_STATUS_CHOICES) nationality = CountryField(_('nationality'), default='IN', null=True, blank=True) about = models.TextField(_('about'), blank=True, null=True) dependent = models.ManyToManyField(Dependent, through='DependentRelationship') pan_card_number = models.CharField(_('PAN card number'), max_length=50, blank=True, null=True) policy_number = models.CharField(_('policy number'), max_length=50, null=True, blank=True) # code specific details user = models.OneToOneField(User, blank=True, null=True, verbose_name=_('user')) class Person(models.Model): """Person model""" title = models.CharField(_('title'), max_length=20, null=True, blank=True) first_name = models.CharField(_('first name'), max_length=100) middle_name = models.CharField(_('middle name'), max_length=100, null=True, blank=True) last_name = models.CharField(_('last name'), max_length=100, null=True, blank=True) suffix = models.CharField(_('suffix'), max_length=20, null=True, blank=True) slug = models.SlugField(_('slug'), max_length=50, unique=True) class PhoneNumber(models.Model) : phone_number = generic.GenericRelation('PhoneNumber') email_address = generic.GenericRelation('EmailAddress') address = generic.GenericRelation('Address') date_of_birth = models.DateField(_('date of birth'), null=True, blank=True) gender = models.CharField(_('gender'), max_length=1, null=True, blank=True, choices=GENDER_CHOICES) content_type = models.ForeignKey(ContentType, If anyone could suggest me a link or so. it would be a great help........

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• Mysql - Help me alter this search query to get desired results

  - by sandeepan-nath

  Following is a dump of the tables and data needed to answer understand the system:- The system consists of tutors and classes. The data in the table All_Tag_Relations stores tag relations for each tutor registered and each class created by a tutor. The tag relations are used for searching classes. CREATE TABLE IF NOT EXISTS `Tags` ( `id_tag` int(10) unsigned NOT NULL auto_increment, `tag` varchar(255) default NULL, PRIMARY KEY (`id_tag`), UNIQUE KEY `tag` (`tag`), KEY `id_tag` (`id_tag`), KEY `tag_2` (`tag`), KEY `tag_3` (`tag`), KEY `tag_4` (`tag`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1; INSERT INTO `Tags` (`id_tag`, `tag`) VALUES (1, 'Sandeepan'), (2, 'Nath'), (3, 'first'), (4, 'class'), (5, 'new'), (6, 'Bob'), (7, 'Cratchit'); CREATE TABLE IF NOT EXISTS `All_Tag_Relations` ( `id_tag` int(10) unsigned NOT NULL default '0', `id_tutor` int(10) default NULL, `id_wc` int(10) unsigned default NULL, KEY `All_Tag_Relations_FKIndex1` (`id_tag`), KEY `id_wc` (`id_wc`), KEY `id_tag` (`id_tag`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1; INSERT INTO `All_Tag_Relations` (`id_tag`, `id_tutor`, `id_wc`) VALUES (1, 1, NULL), (2, 1, NULL), (3, 1, 1), (4, 1, 1), (6, 2, NULL), (7, 2, NULL), (5, 2, 2), (4, 2, 2); Following is my query:- This query searches for "first class" (tag for first = 3 and for class = 4, in Tags table) and returns all those classes such that both the terms first and class are present in the class name. SELECT wtagrels.id_wc,SUM(DISTINCT( wtagrels.id_tag =3)) AS key_1_total_matches, SUM(DISTINCT( wtagrels.id_tag =4)) AS key_2_total_matches FROM all_tag_relations AS wtagrels WHERE ( wtagrels.id_tag =3 OR wtagrels.id_tag =4 ) GROUP BY wtagrels.id_wc HAVING key_1_total_matches = 1 AND key_2_total_matches = 1 LIMIT 0, 20 And it returns the class with id_wc = 1. But, I want the search to show all those classes such that all the search terms are present in the class name or its tutor name So that searching "Sandeepan class" (wtagrels.id_tag = 1,4) or "Sandeepan Nath" also returns the class with id_wc=1. And Searching. Searching "Bob First" should not return any classes. Please modify the above query or suggest a new query, if possible using MyIsam - fulltext search, but somehow help me get the result.

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• Javascript : Submitting a form outside the actual form doesn't work

  - by Ben Fransen

  Hello all, I'm trying to achieve a fairly easy triggering mechanism for deleting multiple items from a tablegrid. If a user has enough access he/she is able to delete multiple users from a table. In the table I have set up checkboxes, one per row/user. The name of the checkboxes is UsersToDeletep[], and the value per row is the unique UserID. When a user clicks the button 'Delete selected users' a simple validation takes place to make sure at least one checkbox is selected. After that I call my simple function Submit(form). The function works perfectly when called within the form-tags, where I also use it to delete a single user. The function: function Submit(form) { document.forms[form].submit(); } I've also alerted document.forms[form]. The result is, as expected [object HTMLFormElement]. But for some reason the form just won't submit and a pagereload takes place. I'm a bit confused and can't seem to figure out what I'm doing wrong. Can anyone point me in the right direction? Thanks in advance! Ben

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• Web Hosting URL Length Limit?

  - by Isaac Waller

  Hello, I am designing a web application which is a tie in to my iPhone application. It sends massively large URLs to the web server (15000 about.) I was using NearlyFreeSpeech.net, but they only support URLS up to 2000 characters. I was wondering if anybody knows of web hosting that will support really large URLs? Thanks, Isaac Edit: My program needs to open a picture in Safari. I could do this 2 ways: send it base64 encoded in the URL and just echo the query parameters. first POST it to the server in my application, then the server would send back a unique ID after storing the photo in a database, which I would append to a URL which I would open in Safari which retrieved the photo from the database and delete it from the database. You see, I am lazy, and I know Mobile Safari can support URI's up to 80 000 characters, so I think this is a OK way to do it. If there is something really wrong with this, please tell me. Edit: I ended up doing it the proper POST way. Thanks.

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