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  • Best design for a memory resident tool

    - by Andrew S.
    I apologize if this tends more toward design that programming, but here goes. What design would you recommend for a database that is Memory resident Must run on windows, linux and (at a stretch) the mac Accept multiple queries simultaneously Have minimum overhead, since a search is expected to take <0.25s This program implements a domain-specific search. Think of it as a database, but one that takes advantage of domain specific information to outperform a convential database search (for example, with custom oracle indexing). We have a custom data structure for our data. Our protoype is a simple exe that constructs the database in memory each time it is run. We were thinking that perhaps this program would suffice, but augmented with sockets so it can listen for queries. This database will be static. Its contents will change infrequently. We expect queries, and the solution, to be delivered via a web service.

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  • Grouping a comma separated value on common data [closed]

    - by Ankit
    I have a table with col1 id int, col2 as varchar (comma separated values) and column 3 for assigning group to them. Table looks like col1 col2 group .............................. 1 2,3,4 2 5,6 3 1,2,5 4 7,8 5 11,3 6 22,8 This is only the sample of real data, now I have to assign a group no to them in such a way that output looks like col1 col2 group .............................. 1 2,3,4 1 2 5,6 1 3 1,2,5 1 4 7,8 2 5 11,3 1 6 22,8 2 The logic for assigning group no is that every similar comma separated value of string in col2 have to be same group no as every where in col2 where '2' is there it has to be same group no but the complication is that 2,3,4 are together so they all three int value if found in any where in col2 will be assigned same group. The major part is 2,3,4 and 1,2,5 both in col2 have 2 so all int 1,2,3,4,5 have to assign same group no. Tried store procedure with match against on col2 but not getting desired result Most imp (I can't use normalization, because I can't afford to make new table from my original table which have millions of records), even normalization is not helpful in my context. This question is also on stackoverflow with bounty on this link Achieved so far:- I have set the group column auto increment and then wrote this procedure:- BEGIN declare cil1_new,col2_new,group_new int; declare done tinyint default 0; declare group_new varchar(100); declare cur1 cursor for select col1,col2,`group` from company ; DECLARE CONTINUE HANDLER FOR NOT FOUND SET done=1; open cur1; REPEAT fetch cur1 into col1_new,col2_new,group_new; update company set group=group_new where match(col2) against(concat("'",col2_new,"'")); until done end repeat; close cur1; select * from company; END This procedure is working, no syntax mistake but the problem is that I am not achieving the desired result exactly.

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  • The QueryExtender web server control

    - by nikolaosk
    In this post I am going to present a hands on example on how to use the QueryExtender web server control. It is built into ASP.Net 4.0 and it is available from the Toolbox in VS 2010.Before we move on with our example let me explain what this control does and why we need it. Its goal is to extend the functionality of the LINQ to Entities and LINQ to SQL datasources.Most of the times when we have data coming out from a datasource we want some sort of filtering. We do achieve that by using a Where...(read more)

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  • Scream if you want to go faster

    - by simonsabin
    My session for 24hrs of pass on High Performance functions will be starting at 11:00 GMT thats migdnight for folks in the UK. To attend follow this link https://www.livemeeting.com/cc/8000181573/join?id=N5Q8S7&role=attend&pw=d2%28_KmN3r The rest of the sessions can be found here http://www.sqlpass.org/24hours/2010/Sessions/ChronologicalOrder.aspx So far the sessions have been great so no pressure :( See you there in 4.5 hrs...(read more)

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  • Alternative to NV Occlusion Query - getting the number of fragments which passed the depth test

    - by Etan
    In "modern" environments, the "NV Occlusion Query" extension provide a method to get the number of fragments which passed the depth test. However, on the iPad / iPhone using OpenGL ES, the extension is not available. What is the most performant approach to implement a similar behaviour in the fragment shader? Some of my ideas: Render the object completely in white, then count all the colors together using a two-pass shader where first a vertical line is rendered and for each fragment the shader computes the sum over the whole row. Then, a single vertex is rendered whose fragment sums all the partial sums of the first pass. Doesn't seem to be very efficient. Render the object completely in white over a black background. Downsample recursively, abusing the hardware linear interpolation between textures until being at a reasonably small resolution. This leads to fragments which have a greyscale level depending on the number of white pixels where in their corresponding region. Is this even accurate enough? ... ?

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  • No Obvious Answer - Query-Strings and Javascript

    - by nchaud
    Say I have this main page /my-site/all-my-bath-soaps which lists all my products. It has a search filter text box that uses javascript to filter the products they want to see on that page (the URL doesn't change as they filter). Now from many other parts of the site I want to navigate to this products-page and see specific products. E.g. <a href="/my-site/all-my-bath-soaps?filter='Nivea-Soap'"> will go to /all-my-bath-soaps and apply javascript filtering to see just that product and hide all dom nodes for the other products. The problem is if the user changes the text in the filter from 'Nivea-Soap' to 'Lynx' the javascript will work fine and show the new products but the URL stays at ?filter='Nivea-Soap'. Is there anything I can do about this? Of course, I don't want to reload the page with a new query string every time they change the search criteria. Somehow it'd be great to move the ?filter=... criteria into POST data instead - but how can I do this with a link I don't know...

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  • Fusion Applications Announces the Online Feature Query Tool

    - by Richard Lefebvre
    Fusion Applications Development is pleased to announce the availability of a new, online tool for viewing Fusion Features. Oracle Product Features allows you to view new features in Fusion across multiple releases, families and products. You can view online or download the data in a variety of formats, including pdf and xls. This easy-to-use tool covers the same content and therefore replaces the pdf versions of the What's New documents. You can access Oracle Product Features from the Fusion Learning Center under Featured Assets > Product Features Query Tool. It can also be found under Release Readiness > Release Overview. Oracle Product Features will be available to customers and Partners from MyOracleSupport, oracle.com and the Partner Network Fusion Learning Center in the near future.  Oracle Product Features provides you with a high level of flexibility allowing you to only see the content you want, whether it is for a single Fusion product family, such as Human Capital Management (HCM), across several releases, or to view the entire listing of new features.  Content currently incorporates all new features introduced in Releases 3, 4 and 5. Release 6 content will be added in the near future.

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  • IIS 6 nested virtual directory redirection

    - by threedaysatsea
    We're running IIS 6 on a WinServer2k3 box and we're having some trouble with the following problem: E-mails were sent out to users asking them to go to the following URL: alias.contoso.com/directory2/view.aspx?queryparam1=no&queryparam2=blue However, the URLS are actually supposed to be: server.contoso.com/directory2/view.aspx?queryparam1=no&queryparam2=blue It's too late to recall all of the e-mails, and we'd like to redirect traffic to make this as seamless as possible for our users. The real problem here is that the server (server.contoso.com) is hosting the alias (alias.contoso.com) as a redirect thusly, and the existing redirect we need to keep functional: Default Web Site (server.contoso.com) --Directory1 --Directory2 --Directory3 Redirection to Directory3 (alias.contoso.com) --Essentially alias.contoso.com will take the user to server.contoso.com/Directory3 Is there any way to host a separate redirect inside of the existing redirect? We need to keep alias.contoso.com taking the user to server.contoso.com/Directory3 but also make alias.contoso.com/directory2/view.aspx?queryparam1=no&queryparam2=blue point to server.contoso.com/directory2/view.aspx?queryparam1=no&queryparam2=blue Any tips? Is this even possible?

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  • Query for server DefaultData & DefaultLog folders

    - by jamiet
    Do you ever need to query for the DefaultData & DefaultLog folders for your SQL Server instance? Well, I just did and the following script enabled me to do that: DECLARE @HkeyLocal NVARCHAR(18),@MSSqlServerRegPath NVARCHAR(31),@InstanceRegPath SYSNAME; SELECT @HkeyLocal=N'HKEY_LOCAL_MACHINE' SELECT @MSSqlServerRegPath=N'SOFTWARE\Microsoft\MSSQLServer' SELECT @InstanceRegPath=@MSSqlServerRegPath + N'\MSSQLServer' DECLARE @SmoDefaultFile NVARCHAR(512) EXEC MASTER.dbo.xp_instance_regread @HkeyLocal, @InstanceRegPath, N'DefaultData', @SmoDefaultFile OUTPUT DECLARE @SmoDefaultLog NVARCHAR(512) EXEC MASTER.dbo.xp_instance_regread @HkeyLocal, @InstanceRegPath, N'DefaultLog', @SmoDefaultLog OUTPUT SELECT ISNULL(@SmoDefaultFile,N'') AS [DefaultFile],ISNULL(@SmoDefaultLog,N'') AS [DefaultLog]' I haven’t done any rigorous testing or anything like that, all I can say is…it worked for me (on SQL Server 2012). Use as you see fit. Doubtless this information exists in a multitude of other places but nevertheless I’m putting it here so I know where to find it in the future. Just for fun I thought I’d try this out against SQL Azure Windows Azure SQL Database. Unsurprisingly it didn’t work there: Msg 40515, Level 15, State 1, Line 16 Reference to database and/or server name in 'MASTER.dbo.xp_instance_regread' is not supported in this version of SQL Server. @Jamiet

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  • NotSupportedException on IQuery's Enumerable when using statelesssession

    - by user57555
    when trying to use the Enumerable method on a named query, with a Stateless session, as shown in the example at: http://www.nhforge.org/doc/nh/en/#batch-statelesssession i am seeing a NotSupportedException. the stack trace is as below: System.NotSupportedException: Specified method is not supported. at NHibernate.Impl.StatelessSessionImpl.Enumerable(String query, QueryParameters parameters) at NHibernate.Impl.QueryImpl.Enumerable() here is a snippet of my code: IStatelessSession statelessSession = sessionFactory.OpenStatelessSession(); var fileLines = statelessSession.GetNamedQuery("GetLinesByFileId") .SetInt32("FileIdInput", fileId).Enumerable<FileLineEntity>(); the named query, GetLinesByFileId is defined in the hbm as below: <query name="GetLinesByFileId" cacheable="false" read-only="true"> <![CDATA[ from FileLineEntity lineItem where lineItem.FileId=:FileIdInput ]]> </query> any suggestions on what i maybe missing here?

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  • mysql partitioning

    - by Yang
    just want to verify that database partition is implemented only at the database level, when we query a partitioned table, we still do our normal query, nothing special with our queries, the optimization is performed automatically when parsing the query, is that correct? e.g. we have a table called 'address' with a column called 'country_code' and 'city'. so if i want to get all the addresses in New York, US, normally i wound do something like this: select * from address where country_code = 'US' and city = 'New York' if now the table is partitioned by 'country_code', and i know that now the query will only be executed on the partition which contains country_code = US. My question is do I need to explicitly specify the partition to query in my sql statement? or i still use the previous statement and the db server will optimize it automatically? Thanks in advance!

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  • Why does Sql Server recommends creating an index when it already exist?

    - by Pierre-Alain Vigeant
    I ran a very basic query against one of our table and I noticed that the execution plan query processor is recommending that we create an index on a column The query is SELECT SUM(DATALENGTH(Data)) FROM Item WHERE Namespace = 'http://some_url/some_namespace/' After running, I get the following message // The Query Processor estimates that implementing the following index could improve the query cost by 96.7211%. CREATE NONCLUSTERED INDEX [<Name of Missing Index, sysname,>] ON [dbo].[Item] ([Namespace]) My problem is that I already have such index on that column: CREATE NONCLUSTERED INDEX [IX_ItemNamespace] ON [dbo].[Item] ( [Namespace] ASC )WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, SORT_IN_TEMPDB = OFF, IGNORE_DUP_KEY = OFF, DROP_EXISTING = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] Why is Sql Server recommending me to create such index when it already exist?

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  • MySQL parameter resource error

    - by Derek
    Here is my error: Warning: mysql_query() expects parameter 2 to be resource, null given... This refers to line 23 of my code which is: $result = mysql_query($sql, $connection) My entire query code looks like this: $query = "SELECT * from users WHERE userid='".intval( $_SESSION['SESS_USERID'] )."'"; $result = mysql_query($query, $connection) or die ("Couldn't perform query $query <br />".mysql_error()); $row = mysql_fetch_array($result); I don't have a clue what has happpened here. All I wanted to do was to have the value of the users 'fullname' displayed in the header section of my web page. So I am outputting this code immediately after to try and achieve this: echo 'Hello '; echo $row['fullname']; Before this change, I had it working perfectly, where the session variable of fullname was echoed $_SESSION['SESS_NAME']. However, because my user can update their information (including their name), I wanted the name displayed in the header to be updated accordingly, and not displaying the session value.

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  • Mysql - Grouping the result based on a mathematical operation and SUM() function

    - by SpikETidE
    Hi all... I'm having the following two tables... Table : room_type type_id type_name no_of_rooms max_guests rate 1 Type 1 15 2 1254 2 Type 2 10 1 3025 Table : reservation reservation_id start_date end_date room_type booked_rooms 1 2010-04-12 2010-04-15 1 8 2 2010-04-12 2010-04-15 1 2 Now... I have this query SELECT type_id, type_name FROM room_type WHERE id NOT IN (SELECT room_type FROM reservation WHERE start_date >= '$start_date' AND end_date <= '$end_date') What the query does is it selects the rooms that are not booked between the start date and end date. Also, as you can see from the reservation table, we also have 'number of rooms booked between the two dates' factor also... I need to add this 'no.of booked rooms between the two dates' factor also in to the query... The query should return the type of rooms for which at least one room is free between the two dates. I worked out the logic but just can't represent it as a query....! How will you do this...? Thanks for your suggestions..!

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  • Which index is used in select and why?

    - by Lukasz Lysik
    I have the table with zip codes with following columns: id - PRIMARY KEY code - NONCLUSTERED INDEX city When I execute query SELECT TOP 10 * FROM ZIPCodes I get the results sorted by id column. But when I change the query to: SELECT TOP 10 id FROM ZIPCodes I get the results sorted by code column. Again, when I change the query to: SELECT TOP 10 code FROM ZIPCodes I get the results sorted by code column again. And finally when I change to: SELECT TOP 10 id,code FROM ZIPCodes I get the results sorted by id column. My question is in the title of the question. I know which indexes are used in the queries, but my question is, why those indexes are used? I the second query (SELECT TOP 10 id FROM ZIPCodes) wouldn't it be faster if the clusteder index was used? How the query engine chooses which index to use?

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  • mysql - check if data exists across multiple tables

    - by Dd Daym
    I am currently running this query inside MySQL to check if the specified values exists within the table associated with them. SELECT COUNT(artist.artist_id), COUNT(album.album_id), COUNT(tracks.track_id) FROM artist, album, tracks WHERE artist.artist_id = 320295 OR album.album_id = 1234 OR tracks.track_id = 809 The result I get from running this query is all 1, meaning that all the statements after the WHERE clause is true. To further check the query's reliability, I changed the tracks.track_ = 809 to 802, which I know does not match. However the results displayed are still all 1, meaning that they were all successfully matched even when I purposefully inserted a value which would not have matched. How do I get it to show 1 for a match and 0 for no matches within the same query? EDIT: I have inserted an image of the query running

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  • MySQL - Counting rows in preparation for greatest-n-per-group not working?

    - by John M
    Referring to SO and other sites have given me examples of how to use MySQL to create a 'greatest-n-per-group' query. My variant on this would be to have a query that returns the first 3 rows of each category. As the basis for this I need to sort my data into a usable sequence and that is where my problems start. Running just the sequence query with row numbering shows that changes in category are mostly ignored. I should have 35 categories returning rows but only 5 do so. My query: set @c:=0; set @a:=0; SELECT IF(@c = tdg, @a:=@a+1, @a:=1) AS rownum, (@c:=tdg) , julian_day, sequence, complete, year, tdg FROM tsd WHERE complete = 0 order by tdg, year, julian_day, sequence Do I have a syntax mistake with this query?

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  • Access 2007 VBA & SQL - Update a Subform pointed at a dynamically created query

    - by Lucretius
    Abstract: I'm using VB to recreate a query each time a user selects one of 3 options from a drop down menu, which appends the WHERE clause If they've selected anything from the combo boxes. I then am attempting to get the information displayed on the form to refresh thereby filtering what is displayed in the table based on user input. 1) Dynamically created query using VB. Private Sub BuildQuery() ' This sub routine will redefine the subQryAllJobsQuery based on input from ' the user on the Management tab. Dim strQryName As String Dim strSql As String ' Main SQL SELECT statement Dim strWhere As String ' Optional WHERE clause Dim qryDef As DAO.QueryDef Dim dbs As DAO.Database strQryName = "qryAllOpenJobs" strSql = "SELECT * FROM tblOpenJobs" Set dbs = CurrentDb ' In case the query already exists we should deleted it ' so that we can rebuild it. The ObjectExists() function ' calls a public function in GlobalVariables module. If ObjectExists("Query", strQryName) Then DoCmd.DeleteObject acQuery, strQryName End If ' Check to see if anything was selected from the Shift ' Drop down menu. If so, begin the where clause. If Not IsNull(Me.cboShift.Value) Then strWhere = "WHERE tblOpenJobs.[Shift] = '" & Me.cboShift.Value & "'" End If ' Check to see if anything was selected from the Department ' drop down menu. If so, append or begin the where clause. If Not IsNull(Me.cboDepartment.Value) Then If IsNull(strWhere) Then strWhere = strWhere & " AND tblOpenJobs.[Department] = '" & Me.cboDepartment.Value & "'" Else strWhere = "WHERE tblOpenJobs.[Department] = '" & Me.cboDepartment.Value & "'" End If End If ' Check to see if anything was selected from the Date ' field. If so, append or begin the Where clause. If Not IsNull(Me.txtDate.Value) Then If Not IsNull(strWhere) Then strWhere = strWhere & " AND tblOpenJobs.[Date] = '" & Me.txtDate.Value & "'" Else strWhere = "WHERE tblOpenJobs.[Date] = '" & Me.txtDate.Value & "'" End If End If ' Concatenate the Select and the Where clause together ' unless all three parameters are null, in which case return ' just the plain select statement. If IsNull(Me.cboShift.Value) And IsNull(Me.cboDepartment.Value) And IsNull(Me.txtDate.Value) Then Set qryDef = dbs.CreateQueryDef(strQryName, strSql) Else strSql = strSql & " " & strWhere Set qryDef = dbs.CreateQueryDef(strQryName, strSql) End If End Sub 2) Main Form where the user selects items from combo boxes. picture of the main form and sub form http://i48.tinypic.com/25pjw2a.png 3) Subform pointed at the query created in step 1. Chain of events: 1) User selects item from drop down list on the main form. 2) Old query is deleted, new query is generated (same name). 3) Subform pointed at query does not update, but if you open the query by itself the correct results are displayed. Name of the Query: qryAllOpenJobs name of the subform: subQryAllOpenJobs Also, the Row Source of subQryAllOpenJobs = qryAllOpenJobs Name of the main form: frmManagement

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  • Symfony sfDoctrinePager with multiple tables

    - by Zoja
    I was wondering how to get this to run. In my application I have a Category table and Product table. I need to have a pager which combines both Categories and Products for display in one list (first categories then products). Is there a way to get this going ? I tried left joining in the pager's query, but doesn't seem to do the trick.

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  • C++ MySQL++ Delete query statement brain killer question

    - by shauny
    Hello all, I'm relatively new to the MySQL++ connector in C++, and have an really annoying issue with it already! I've managed to get stored procedures working, however i'm having issues with the delete statements. I've looked high and low and have found no documentation with examples. First I thought maybe the code needs to free the query/connection results after calling the stored procedure, but of course MySQL++ doesn't have a free_result method... or does it? Anyways, here's what I've got: #include <iostream> #include <stdio.h> #include <queue> #include <deque> #include <sys/stat.h> #include <mysql++/mysql++.h> #include <boost/thread/thread.hpp> #include "RepositoryQueue.h" using namespace boost; using namespace mysqlpp; class RepositoryChecker { private: bool _isRunning; Connection _con; public: RepositoryChecker() { try { this->_con = Connection(false); this->_con.set_option(new MultiStatementsOption(true)); this->_con.set_option(new ReconnectOption(true)); this->_con.connect("**", "***", "***", "***"); this->ChangeRunningState(true); } catch(const Exception& e) { this->ChangeRunningState(false); } } /** * Thread method which runs and creates the repositories */ void CheckRepositoryQueues() { //while(this->IsRunning()) //{ std::queue<RepositoryQueue> queues = this->GetQueue(); if(queues.size() > 0) { while(!queues.empty()) { RepositoryQueue &q = queues.front(); char cmd[256]; sprintf(cmd, "svnadmin create /home/svn/%s/%s/%s", q.GetPublicStatus().c_str(), q.GetUsername().c_str(), q.GetRepositoryName().c_str()); if(this->DeleteQueuedRepository(q.GetQueueId())) { printf("query deleted?\n"); } printf("Repository created!\n"); queues.pop(); } } boost::this_thread::sleep(boost::posix_time::milliseconds(500)); //} } protected: /** * Gets the latest queue of repositories from the database * and returns them inside a cool queue defined with the * RepositoryQueue class. */ std::queue<RepositoryQueue> GetQueue() { std::queue<RepositoryQueue> queues; Query query = this->_con.query("CALL sp_GetRepositoryQueue();"); StoreQueryResult result = query.store(); RepositoryQueue rQ; if(result.num_rows() > 0) { for(unsigned int i = 0;i < result.num_rows(); ++i) { rQ = RepositoryQueue((unsigned int)result[i][0], (unsigned int)result[i][1], (String)result[i][2], (String)result[i][3], (String)result[i][4], (bool)result[i][5]); queues.push(rQ); } } return queues; } /** * Allows the thread to be shut off. */ void ChangeRunningState(bool isRunning) { this->_isRunning = isRunning; } /** * Returns the running value of the active thread. */ bool IsRunning() { return this->_isRunning; } /** * Deletes the repository from the mysql queue table. This is * only called once it has been created. */ bool DeleteQueuedRepository(unsigned int id) { char cmd[256]; sprintf(cmd, "DELETE FROM RepositoryQueue WHERE Id = %d LIMIT 1;", id); Query query = this->_con.query(cmd); return (query.exec()); } }; I've removed all the other methods as they're not needed... Basically it's the DeleteQueuedRepository method which isn't working, the GetQueue works fine. PS: This is on a Linux OS (Ubuntu server) Many thanks, Shaun

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  • Doctrine_Query update with float value

    - by YS-PRO
    I need to increment User's balance, so I do: Doctrine_Query::create()->from('User')->update('balance', 'balance + 0.15')->execute(); And I got an error "Unknown component alias 0". I think its because of 0.15 So how can I update (using DQL) balance without additional SELECT queries to User's table to fetch his balance, calculate new balance and do query like Doctrine_Query::create()->from('User')->update('balance', '?', $new_balance)->execute();

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  • Problem with PHP/AS3 - Display PHP query results back to flash via AS3

    - by Dale J
    Hi, Ive made a query in PHP, and i'm trying to send the results back into Flash via AS3, but its throwing up this error Error: Error #2101: The String passed to URLVariables.decode() must be a URL-encoded query string containing name/value pairs. at Error$/throwError() at flash.net::URLVariables/decode() at flash.net::URLVariables() at flash.net::URLLoader/onComplete() Here is the relevant part of the PHP and AS3 code, including the query. The flash variable rssAdd is passed over to the PHP which it using it in the PHP query accordingly. $url = $_POST['rssAdd']; $query= SELECT title FROM Feed WHERE category = (SELECT category FROM Feed WHERE url =$url) AND url!=$url; $result = mysql_query($query); echo $query; Here is the AS3 code I've done so far. function recommendation(){ var request:URLRequest = new URLRequest("url"); request.method = URLRequestMethod.POST var recVars:URLVariables = new URLVariables(); recVars.rssAdd=rssAdd; request.data = recVars var loader:URLLoader = new URLLoader(request); loader.addEventListener(Event.COMPLETE, onComplete); loader.dataFormat = URLLoaderDataFormat.TEXT; loader.load(request); function onComplete(event:Event):void{ recommend.text = event.target.data; } } Any help would be most appreciated, thanks.

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  • SQL 2005 indexed queries slower than unindexed queries

    - by uos??
    Adding a seemingly perfectly index is having an unexpectedly adverse affect on a query performance... -- [Data] has a predictable structure and a simple clustered index of the primary key: ALTER TABLE [dbo].[Data] ADD PRIMARY KEY CLUSTERED ( [ID] ) -- My query, joins on itself looking for a certain kind of "overlapping" records SELECT DISTINCT [Data].ID AS [ID] FROM dbo.[Data] AS [Data] JOIN dbo.[Data] AS [Compared] ON [Data].[A] = [Compared].[A] AND [Data].[B] = [Compared].[B] AND [Data].[C] = [Compared].[C] AND ([Data].[D] = [Compared].[D] OR [Data].[E] = [Compared].[E]) AND [Data].[F] <> [Compared].[F] WHERE 1=1 AND [Data].[A] = @A AND @CS <= [Data].[C] AND [Data].[C] < @CE -- Between a range [Data] has about a quarter-million records so far, 10% to 50% of the data satisfies the where clause depending on @A, @CS, and @CE. As is, the query takes 1 second to return about 300 rows when querying 10%, and 30 seconds to return 3000 rows when querying 50% of the data. Curiously, the estimated/actual execution plan indicates two parallel Clustered Index Scans, but the clustered index is only of the ID, which isn't part of the conditions of the query, only the output. ?? If I add this hand-crafted [IDX_A_B_C_D_E_F] index which I fully expected to improve performance, the query slows down by a factor of 8 (8 seconds for 10% & 4 minutes for 50%). The estimated/actual execution plans show an Index Seek, which seems like the right thing to be doing, but why so slow?? CREATE UNIQUE INDEX [IDX_A_B_C_D_E_F] ON [dbo].[Data] ([A], [B], [C], [D], [E], [F]) INCLUDE ([ID], [X], [Y], [Z]); The Data Engine Tuning wizard suggests a similar index with no noticeable difference in performance from this one. Moving AND [Data].[F] <> [Compared].[F] from the join condition to the where clause makes no difference in performance. I need these and other indexes for other queries. I'm sure I could hint that the query should refer to the Clustered Index, since that's currently winning - but we all know it is not as optimized as it could be, and without a proper index, I can expect the performance will get much worse with additional data. What gives?

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  • SQL Where Clause Against View

    - by Adam Carr
    I have a view (actually, it's a table valued function, but the observed behavior is the same in both) that inner joins and left outer joins several other tables. When I query this view with a where clause similar to SELECT * FROM [v_MyView] WHERE [Name] like '%Doe, John%' ... the query is very slow, but if I do the following... SELECT * FROM [v_MyView] WHERE [ID] in ( SELECT [ID] FROM [v_MyView] WHERE [Name] like '%Doe, John%' ) it is MUCH faster. The first query is taking at least 2 minutes to return, if not longer where the second query will return in less than 5 seconds. Any suggestions on how I can improve this? If I run the whole command as one SQL statement (without the use of a view) it is very fast as well. I believe this result is because of how a view should behave as a table in that if a view has OUTER JOINS, GROUP BYS or TOP ##, if the where clause was interpreted prior to vs after the execution of the view, the results could differ. My question is why wouldn't SQL optimize my first query to something as efficient as my second query?

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