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  • Need advice on comparing the performance of 2 equivalent linq to sql queries

    - by uvita
    I am working on tool to optimize linq to sql queries. Basically it intercepts the linq execution pipeline and makes some optimizations like for example removing a redundant join from a query. Of course, there is an overhead in the execution time before the query gets executed in the dbms, but then, the query should be processed faster. I don't want to use a sql profiler because I know that the generated query will be perform better in the dbms than the original one, I am looking for a correct way of measuring the global time between the creation of the query in linq and the end of its execution. Currently, I am using the Stopwatch class and my code looks something like this: var sw = new Stopwatch(); sw.Start(); const int amount = 100; for (var i = 0; i < amount; i++) { ExecuteNonOptimizedQuery(); } sw.Stop(); Console.Writeline("Executing the query {2} times took: {0}ms. On average, each query took: {1}ms", sw.ElapsedMilliseconds, sw.ElapsedMilliseconds / amount, amount); Basically the ExecutenNonOptimizedQuery() method creates a new DataContext, creates a query and then iterates over the results. I did this for both versions of the query, the normal one and the optimized one. I took the idea from this post from Frans Bouma. Is there any other approach/considerations I should take? Thanks in advance!

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  • Lucene wildcard queries

    - by Javi
    Hello, I have this question relating to Lucene. I have a form and I get a text from it and I want to perform a full text search in several fields. Suppose I get from the input the text "textToLook". I have a Lucene Analyzer with several filters. One of them is lowerCaseFilter, so when I create the index, words will be lowercased. Imagine I want to search into two fields field1 and field2 so the lucene query would be something like this (note that 'textToLook' now is 'texttolook'): field1: texttolook* field2:texttolook* In my class I have something like this to create the query. I works when there is no wildcard. String text = "textToLook"; String[] fields = {"field1", "field2"}; //analyser is the same as the one used for indexing Analyzer analyzer = fullTextEntityManager.getSearchFactory().getAnalyzer("customAnalyzer"); MultiFieldQueryParser parser = new MultiFieldQueryParser(fields, analyzer); org.apache.lucene.search.Query queryTextoLibre = parser.parse(text); With this code the query would be: field1: texttolook field2:texttolook but If I set text to "textToLook*" I get field1: textToLook* field2:textToLook* which won't find correctly as the indexes are in lowercase. I have read in lucene website this: " Wildcard, Prefix, and Fuzzy queries are not passed through the Analyzer, which is the component that performs operations such as stemming and lowercasing" My problem cannot be solved by setting the behaviour case insensitive cause my analyzer has other fields which for examples remove some suffixes of words. I think I can solve the problem by getting how the text would be after going through the filters of my analyzer, then I could add the "*" and then I could build the Query with MultiFieldQueryParser. So in this example I woud get "textToLower" and after being passed to to these filters I could get "texttolower". After this I could make "textotolower*". But, is there any way to get the value of my text variable after going through all my analyzer's filters? How can I get all the filters of my analyzer? Is this possible? Thanks

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  • Heterogeneous queries require the ANSI_NULLS

    - by Dezigo
    I wrote a trigger. USE [TEST] GO /****** Object: Trigger [dbo].[TR_POSTGRESQL_UPDATE_YC] Script Date: 05/26/2010 08:54:03 ******/ SET ANSI_NULLS ON GO SET QUOTED_IDENTIFIER ON GO ALTER TRIGGER [dbo].[TR_POSTGRESQL_UPDATE_YC] ON [dbo].[BCT_CNTR_EVENTS] FOR INSERT AS BEGIN DECLARE @MOVE_TIME varchar(14); DECLARE @MOVE_TIME_FORMATED varchar(20); DECLARE @RELEASE_NOTE varchar(32); DECLARE @CMR_NUMBER varchar(15); DECLARE @MOVE_TYPE varchar(2); SELECT @MOVE_TIME = inserted.move_time ,@MOVE_TYPE = inserted.move_type ,@RELEASE_NOTE = inserted.release_note ,@CMR_NUMBER = inserted.cmr_number FROM inserted IF(@MOVE_TYPE = 'YC') BEGIN SET @MOVE_TIME_FORMATED = SUBSTRING(@MOVE_TIME,1,4) + '-' + SUBSTRING(@MOVE_TIME,5,2) + '-' + SUBSTRING(@MOVE_TIME,7,2) + ' 00:00:00' --UPDATE OpenQuery(POSTGRESQL_SERV,'SELECT visit_cmr,visit_timestamp,visit_pin FROM VISIT') -- SET visit_cmr = @RELEASE_NOTE -- WHERE visit_timestamp = @MOVE_TIME_FORMATED -- AND visit_pin = right(@CMR_NUMBER,5) -- AND visit_cmr IS NULL END SET NOCOUNT ON; END When I have inserted a row,I have get an error **Heterogeneous queries require the ANSI_NULLS and ANSI_WARNINGS options to be set for the connection. This ensures consistent query semantics. Enable these options and then reissue your query.** Then I ofcourse SET SET ANSI_WARNINGS is ON but it`s not work for me. (trigger fo linked server postgresql) I have restarted a server. not work again.

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  • SQL Queries SELECT IN and SELECT NOT IN

    - by Sequenzia
    Does anyone know why the results of the following 2 queries do not add up to the results of the 3rd one? SELECT COUNT(leadID) FROM leads WHERE makeID NOT IN (SELECT uploadDataMapID FROM DG_App.dbo.uploadData WHERE uploadID = 3 AND uploadRowID = 1) AND modelID NOT IN (SELECT uploadDataMapID FROM DG_App.dbo.uploadData WHERE uploadID = 3 AND uploadRowID = 2) SELECT COUNT(leadID) FROM Leads WHERE makeID IN (SELECT uploadDataMapID FROM DG_App.dbo.uploadData WHERE uploadID = 3 AND uploadRowID = 1) OR modelID IN (SELECT uploadDataMapID FROM DG_App.dbo.uploadData WHERE uploadID = 3 AND uploadRowID = 2) SELECT COUNT(leadID) FROM Leads The first query is the count I need. The second one is to tell the user how many records were suppressed based on the contents of the DG_App.dbo.uploadData table. The third query is just a straight count of all the records. When I run these the results of query 1 + the results of query 2 comes up about 46K records less than the count of the entire table. I have played with grouping the WHERE statements with () but that did not change the counts at all. This is MSSQL Server 2012. Any input on this would be great. Thanks

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  • Mysql and PHP - Reading multiple insert queries from a file and executing at runtime

    - by SpikETidE
    Hi everyone... I am trying out a back-up and restore system. Basically, what i try to do is, when creating the back up i make a file which looks like DELETE FROM bank_account; INSERT INTO bank_account VALUES('1', 'IB6872', 'Indian Bank', 'Indian Bank', '2', '1', '0', '0000-00-00 00:00:00', '1', '2010-04-13 17:09:05');INSERT INTO bank_account VALUES('2', 'IB7391', 'Indian Bank', 'Indian Bank', '3', '1', '0', '0000-00-00 00:00:00', '1', '2010-04-13 17:09:32'); and so on and so forth. When i restore the db i just read the query from the file, save it to a string and then execute it over the DB using mysql_query(); The problem is, when i run the query through mysql_query(), the execution stops after the delete query with the error 'Error in syntax near '; INSERT INTO bank_account VALUES('1', 'IB6872', 'Indian Bank', 'Indian Bank', '2',' at line 1. But when i run the queries directly over the Db, using phpmyadmin it executes without any errors. As far as i can see, i can't notice any syntax error in the query. Can anyone point out where there might be a glitch...? Thanks and regards....

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  • How can I manage a FIFO-queue in an database with SQL?

    - by Jonas
    I have two tables in my database, one for In and one for Out. They have two columns, Quantity and Price. How can I write a SQL-query that selects the correct price? In example: If I have 3 items in for 75 and then 3 items in for 80. Then I have two out for 75, and the third out should be for 75 (X) and the fourth out should be for 80 (Y). How can I write the price query for X and Y? They should use the price from the third and forth row. In example, is there any way to SELECT the third row in the In-table? I can not use auto_increment as identifier for i.e. "third" row, because the tables will contain post for other items too. The rows will not be deleted, they will be saved for accountability reasons. SELECT Price FROM In WHERE ...? NEW database design: +----+ | In | +----+------+-------+ | Supply_ID | Price | +-----------+-------+ | 1 | 75 | | 1 | 75 | | 1 | 75 | | 2 | 80 | | 2 | 80 | +-----------+-------+ +-----+ | Out | +-----+-------+-------+ | Delivery_ID | Price | +-------------+-------+ | 1 | 75 | | 1 | 75 | | 2 | X | <- ? | 3 | Y | <- ? +-------------+-------+ OLD database design: +----+ | In | +----+------+----------+-------+ | Supply_ID | Quantity | Price | +-----------+----------+-------+ | 1 | 3 | 75 | | 2 | 3 | 80 | +-----------+----------+-------+ +-----+ | Out | +-----+-------+----------+-------+ | Delivery_ID | Quantity | Price | +-------------+----------+-------+ | 1 | 2 | 75 | | 2 | 1 | X | <- ? | 3 | 1 | Y | <- ? +-------------+----------+-------+

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  • Playframework sends 2 queries for fetched query

    - by MRu
    I currently have problems with the JPA at the play framework 1.2.4. I need to have a UserOptions model in a separate database and want to join it lazyly cause its only needed in one query. In this query I want to load the options eagerly and by searching I found out that can only be done by using a join query. If I use eager instead oder lazy, everything would be fine by using User.findById() and the options and the user is found in one query. But play sends two queries when I use a 'left join fetch' query. So heres the query: User.find(" SELECT user FROM User user LEFT JOIN FETCH user.options options WHERE user.id = ? ", Long.parseLong(id)).first(); And here the models: @Entity public class User extends Model { @OneToOne(mappedBy = "user", fetch = FetchType.LAZY) public UserOptions options; // ... } @Entity public class UserOptions extends Model { @OneToOne(fetch = FetchType.LAZY) public User user; } The question is why play sends two query for the fetch query? Thanks in advance

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  • How can manage a FIFO-queue in an database with SQL?

    - by Jonas
    I have two tables in my database, one for In and one for Out. They have two columns, Quantity and Price. How can I write a SQL-query that selects the correct price? In example: If I have 3 items in for 75 and then 3 items in for 80. Then I have two out for 75, and the third out should be for 75 (X) and the fourth out should be for 80 (Y). How can I write the price query for X and Y? They should use the price from the third and forth row. In example, is there any way to SELECT the third row in the In-table? I can not use auto_increment as identifier for i.e. "third" row, because the tables will contain post for other items too. The rows will not be deleted, they will be saved for accountability reasons. SELECT Price FROM In WHERE ...? NEW database design: +----+ | In | +----+------+-------+ | Supply_ID | Price | +-----------+-------+ | 1 | 75 | | 1 | 75 | | 1 | 75 | | 2 | 80 | | 2 | 80 | +-----------+-------+ +-----+ | Out | +-----+-------+-------+ | Delivery_ID | Price | +-------------+-------+ | 1 | 75 | | 1 | 75 | | 2 | X | <- ? | 3 | Y | <- ? +-------------+-------+ OLD database design: +----+ | In | +----+------+----------+-------+ | Supply_ID | Quantity | Price | +-----------+----------+-------+ | 1 | 3 | 75 | | 2 | 3 | 80 | +-----------+----------+-------+ +-----+ | Out | +-----+-------+----------+-------+ | Delivery_ID | Quantity | Price | +-------------+----------+-------+ | 1 | 2 | 75 | | 2 | 1 | X | <- ? | 3 | 1 | Y | <- ? +-------------+----------+-------+

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  • At what point is it worth using a database?

    - by radix07
    I have a question relating to databases and at what point is worth diving into one. I am primarily an embedded engineer, but I am writing an application using QT to interface with our controller. We are at an odd point where we have enough data that it would be feasible to implement a database (around 700+ items and growing) to manage everything, but I am not sure it is worth the time right now to deal with. I have no problems implementing the GUI with files generated from excel and parsed in, but it gets tedious and hard to track even with VBA scripts. I have been playing around with converting our data into something more manageable for the application side with Microsoft Access and that seems to be working well. If that works out I am only a step (or several) away from using an SQL database and using the QT library to access and modify it. I don't have much experience managing data at this level and am curious what may be the best way to approach this. So what are some of the real benefits of using a database if any in this case? I realize much of this can be very application specific, but some general ideas and suggestions on how to straddle the embedded/application programming line would be helpful. Thanks

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  • how to decrease queries in php/mysql array selection loop

    - by Mac Taylor
    hey guys i need to show stories details and tags' names in my php/mysql project . for every story row, there is a filed named : tags that save tags id as an array Table name: stories table filed : tags example of tags filed : 1 5 6 space between them and i have a tag table that looks like this Table name : bt_tags Table fileds : tid,tag now problem : when using while loop to fetch all fields in story table , the page uses 1 query to show every stories' detail but for showing tag's names , i should query another table to find names , we have ids stored in story table now i used for loop between while loop to show tag names but im sure there is a better way to decrease page queries $result = $db->sql_query("SELECT * FROM ".STORY_TABLE." "); while ($row = $db->sql_fetchrow($result)) { //fetching other $vars ---- $tags_id = explode(" ",$row['tags']); $c = count($tags_id); for($i=1;$i<$c-1;$i++){ list($tag_name,$slug) = $db->sql_fetchrow($db->sql_query( 'SELECT `tag`,`slug` FROM `bt_tags` WHERE `tid` = "'.tags_id[$i].'" LIMIT 1' )); $sow_tags = '$tag_name,'; } im not allowed to change anything in database table how can i improve this script and show tag's names without using *for loop ?*

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  • Using array instead of lots of db queries in PHP

    - by Tural Teyyuboglu
    My function looks like that. It works but does lots of work (recursively calls itself and does lots of db queries.). There must be another way to do same thing but with array (with one query). I can't figure out how to modify this function to get it work with array. Please help. function genMenu($parent, $level, $menu, $utype) { global $db; $stmt=$db->prepare("select id, name FROM navigation WHERE parent = ? AND menu=? AND user_type=?") or die($db->error); $stmt->bind_param("iii", $parent, $menu, $utype) or die($stmt->error); $stmt->execute() or die($stmt->error); $stmt->store_result(); /* bind variables to prepared statement */ $stmt->bind_result($id, $name) or die($stmt->error); if ($level > 0 && $stmt->num_rows > 0) { echo "\n<ul>\n"; } while ($stmt->fetch()) { echo "<li>"; echo '<a href="?page=' . $id . '">' . $name . '</a>'; //display this level's children genMenu($id, $level+1, $menu, $utype); echo "</li>\n\n"; } if ($level > 0 && $stmt->num_rows > 0) { echo "</ul>\n"; } $stmt->close(); }

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  • Run multiple MySQL queries based on a series of ifs

    - by OldWest
    I am just getting started on this complex query I need to write and was hoping for any suggestions or feedback regarding table structure and the actual query itself.. I've already created my tables and populated test data, and now just trying to sort out how and what is possible within MySQL. Here is an outline of the problem: End result: Listing of rates based on specific queried criteria (see below): Age: [ 27 ] Spouse Age: [ 25 ] Num of Children: [ 3 ] Zip Code: [ 97128 ] The problem I am running into is each company that provides rates has a unique way of dealing with the rate. And I am looking for the best approach for multiple queries based on the company (one query with results for each company more or less all combined into one result set). Here are some facts: - Each company deals with zip code ranges which assist in the query result. - Each company has a different method of calculating the rate based on the Applicant, Spouse, Num of Children: Example, a) Company A determines rate by: Applicant + Spouse + Child(ren) = rate (age is pertinent to the applicant within a range). b) Company B determines the rate by total number of applicants like: 1, 2, 3, 4, 5, 6+ = rate (and age is ignored). First off, what would I call this type of query? Multiple nested query? And should I intertwine php within it to determine the If()s ... I apologize if this thread lacks sufficient data, so please tell me anything you would like to see.

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  • In Python, how to make sure database connection will always close before leaving a code block?

    - by Cawas
    I want to prevent database connection being open as much as possible, because this code will run on an intensive used server and people here already told me database connections should always be closed as soon as possible. def do_something_that_needs_database (): dbConnection = MySQLdb.connect(host=args['database_host'], user=args['database_user'], passwd=args['database_pass'], db=args['database_tabl'], cursorclass=MySQLdb.cursors.DictCursor) dbCursor = dbConnection.cursor() dbCursor.execute('SELECT COUNT(*) total FROM table') row = dbCursor.fetchone() if row['total'] == 0: print 'error: table have no records' dbCursor.execute('UPDATE table SET field="%s"', whatever_value) return None print 'table is ok' dbCursor.execute('UPDATE table SET field="%s"', another_value) # a lot more of workflow done here dbConnection.close() # even more stuff would come below I believe that leaves a database connection open when there is no row on the table, tho I'm still really not sure how it works. Anyway, maybe that is bad design in the sense that I could open and close a DB connection after each small block of execute. And sure, I could just add a close right before the return in that case... But how could I always properly close the DB without having to worry if I have that return, or a raise, or continue, or whatever in the middle? I'm thinking in something like a code block, similar to using try, like in the following suggestion, which obviously doesn't work: def do_something_that_needs_database (): dbConnection = MySQLdb.connect(host=args['database_host'], user=args['database_user'], passwd=args['database_pass'], db=args['database_tabl'], cursorclass=MySQLdb.cursors.DictCursor) try: dbCursor = dbConnection.cursor() dbCursor.execute('SELECT COUNT(*) total FROM table') row = dbCursor.fetchone() if row['total'] == 0: print 'error: table have no records' dbCursor.execute('UPDATE table SET field="%s"', whatever_value) return None print 'table is ok' dbCursor.execute('UPDATE table SET field="%s"', another_value) # again, that same lot of line codes done here except ExitingCodeBlock: closeDb(dbConnection) # still, that "even more stuff" from before would come below I don't think there is anything similar to ExitingCodeBlock for an exception, tho I know there is the try else, but I hope Python already have a similar feature... Or maybe someone can suggest me a paradigm move and tell me this is awful and highly advise me to never do that. Maybe this is just something to not worry about and let MySQLdb handle it, or is it?

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  • Web services or shared database for (game) server communication?

    - by jaaronfarr
    We have 2 server clusters: the first is made up of typical web applications backed by SQL databases. The second are highly optimized multiplayer game servers which keep all data in memory. Both clusters communicate with clients via HTTP (Ajax with JSON). There are a few cases in which we need to share data between the two server types, for example, reporting back and storing the results of a game (should ultimately end up in the database). We're considering several approaches for inter-server communication: Just share the MySQL databases between clusters (introduce SQL to the game servers) Sharing data in a distributed key-value store like Memcache, Redis, etc. Use an RPC technology like Google ProtoBufs or Apache Thrift Using RESTful web services (the game server would POST back to the web servers, for example) At the moment, we're leaning towards web services or just sharing the database. Sharing the database seems easy, but we're concerned this adds extra memory and a new dependency into the game servers. Web services provide good separation of concerns and fit with the existing Ajax we use, but add complexity, overhead and many more ways for communication to fail. Are there any other good reasons not to use one or the other approach? Which would be easier to scale?

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  • What's the best way to access a MS Access database using PHP?

    - by Jack Roscoe
    Hi, I need to access some data from an MS Access database and retrieve some data from it using PHP. I've looked around the web, and found the following line which seems to correctly connect to the database: $conn->Open("DRIVER={Microsoft Access Driver (*.mdb)}; DBQ=C:\wamp\www\data\MYDB.mdb"); However, I have tried to retrieve some data in the following way: $query = "SELECT pageid FROM pages_table"; $result = mysqli_query($conn, $query); $amount_of_pages = 0; if(mysqli_num_rows($result) <= 0) echo "No results found."; else while($row = mysqli_fetch_array($result, MYSQL_ASSOC)) $amount_of_pages++; And was presented with the following errors: Warning: mysqli_query() expects parameter 1 to be mysqli, object given in C:\wamp\www\data\index.php on line 19 Warning: mysqli_num_rows() expects parameter 1 to be mysqli_result, null given in C:\wamp\www\data\index.php on line 23 No results found. I don't really understand the connection to the Access database, is there something I should be doing differently? Thanks in advance for any help.

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  • sql queries slower than expected

    - by neubert
    Before I show the query here are the relevant table definitions: CREATE TABLE phpbb_posts ( topic_id mediumint(8) UNSIGNED DEFAULT '0' NOT NULL, poster_id mediumint(8) UNSIGNED DEFAULT '0' NOT NULL, KEY topic_id (topic_id), KEY poster_id (poster_id), ); CREATE TABLE phpbb_topics ( topic_id mediumint(8) UNSIGNED NOT NULL auto_increment ); Here's the query I'm trying to do: SELECT p.topic_id, p.poster_id FROM phpbb_topics AS t LEFT JOIN phpbb_posts AS p ON p.topic_id = t.topic_id AND p.poster_id <> ... WHERE p.poster_id IS NULL; Basically, the query is an attempt to find all topics where the number of times someone other than the target user has posted in is zero. In other words, the topics where the only person who has posted is the target user. Problem is that query is taking a super long time. My general assumption when it comes to SQL is that JOINs of any are super fast and can be done in no time at all assuming all relevant columns are primary or foreign keys (which in this case they are). I tried out a few other queries: SELECT COUNT(1) FROM phpbb_topics AS t JOIN phpbb_posts AS p ON p.topic_id = t.topic_id; That returns 353340 pretty quickly. I then do these: SELECT COUNT(1) FROM phpbb_topics AS t JOIN phpbb_posts AS p ON p.topic_id = t.topic_id AND p.poster_id <> 77198; SELECT COUNT(1) FROM phpbb_topics AS t JOIN phpbb_posts AS p ON p.topic_id = t.topic_id WHERE p.poster_id <> 77198; And both of those take quite a while (between 15-30 seconds). If I change the < to a = it takes no time at all. Am I making some incorrect assumptions? Maybe my DB is just foobar'd?

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  • LINQ to SQL Queries odd Materialization

    - by ptoinson
    I ran across an interesting Linq to SQL, uh, feature, the other day. Perhaps someone can give me a logical explanation for the reasoning behind the results. Take the code below as my example which utilizes the AdventureWorks database setup in a Linq to SQL DataContext. This is a clip from my unit test. The resulting customer returned from a call to both CustomerQuery_Test_01() and CustomerQuery_Test_02() is the same. However, the query executed on the SQLServer are different is a major way. The method CustomerQuery_Test_01 us causing the entire Customer table to be materialized, which the call to CustomerQuery_Test_02 is only causing the single customer to be materialized. The resulting SQL Queries are at the bottom of this post. Anyone have a good reason for this? To me, it was highly non-intuitive. protected virtual Customer GetByPrimaryKey(Func<Customer, bool> keySelection) { AdventureWorksDataContext context = new AdventureWorksDataContext(); return (from r in context.Customers select r).SingleOrDefault(keySelection); } [TestMethod] public void CustomerQuery_Test_01() { Customer customer = GetByPrimaryKey(c => c.CustomerID == 2); } [TestMethod] public void CustomerQuery_Test_02() { AdventureWorksDataContext context = new AdventureWorksDataContext(); Customer customer = (from r in context.Customers select r).SingleOrDefault(c => c.CustomerID == 2); } Query for CustomerQuery_Test_01 (notice the lack of a where clause) SELECT [t0].[CustomerID], [t0].[NameStyle], [t0].[Title], [t0].[FirstName], [t0].[MiddleName], [t0].[LastName], [t0].[Suffix], [t0].[CompanyName], [t0].[SalesPerson], [t0].[EmailAddress], [t0].[Phone], [t0].[PasswordHash], [t0].[PasswordSalt], [t0].[rowguid], [t0].[ModifiedDate] FROM [SalesLT].[Customer] AS [t0] Query for CustomerQuery_Test_02 (notice the where clause) SELECT [t0].[CustomerID], [t0].[NameStyle], [t0].[Title], [t0].[FirstName], [t0].[MiddleName], [t0].[LastName], [t0].[Suffix], [t0].[CompanyName], [t0].[SalesPerson], [t0].[EmailAddress], [t0].[Phone], [t0].[PasswordHash], [t0].[PasswordSalt], [t0].[rowguid], [t0].[ModifiedDate] FROM [SalesLT].[Customer] AS [t0] WHERE [t0].[CustomerID] = @p0

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  • Best ways to format LINQ queries.

    - by Aren B
    Before you ignore / vote-to-close this question, I consider this a valid question to ask because code clarity is an important topic of discussion, it's essential to writing maintainable code and I would greatly appreciate answers from those who have come across this before. I've recently run into this problem, LINQ queries can get pretty nasty real quick because of the large amount of nesting. Below are some examples of the differences in formatting that I've come up with (for the same relatively non-complex query) No Formatting var allInventory = system.InventorySources.Select(src => new { Inventory = src.Value.GetInventory(product.OriginalProductId, true), Region = src.Value.Region }).GroupBy(i => i.Region, i => i.Inventory); Elevated Formatting var allInventory = system.InventorySources .Select(src => new { Inventory = src.Value.GetInventory(product.OriginalProductId, true), Region = src.Value.Region }) .GroupBy( i => i.Region, i => i.Inventory); Block Formatting var allInventory = system.InventorySources .Select( src => new { Inventory = src.Value.GetInventory(product.OriginalProductId, true), Region = src.Value.Region }) .GroupBy( i => i.Region, i => i.Inventory ); List Formatting var allInventory = system.InventorySources .Select(src => new { Inventory = src.Value.GetInventory(product.OriginalProductId, true), Region = src.Value.Region }) .GroupBy(i => i.Region, i => i.Inventory); I want to come up with a standard for linq formatting so that it maximizes readability & understanding and looks clean and professional. So far I can't decide so I turn the question to the professionals here.

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  • "like" queries in ASP.net MVC

    - by sslepian
    How do I get wildcard text searches (like SQL's "like" statement) in ASP.net MVC using the edo entity framework? I assumed this would work: var elig = (from e in _documentDataModel.Protocol_Eligibility_View where e.criteria.Contains(query) select e); But it returns no results even when searching for a query string that's definitely in the database. What am I doing wrong?

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  • django: CheckboxMultiSelect problem with db queries

    - by xiackok
    firstly sorry for my bad english there is a simple model Person. That contains just languages: LANGUAGE_LIS = ( (1, 'English'), (2, 'Turkish'), (3, 'Spanish') ) class Person(models.Model): languages = models.CharField(max_length=100, choices=LANGUAGE_LIST) #languages is multi value (CheckBoxSelectMultiple) and here person_save_form: class person_save_form(forms.ModelForm): languages = forms.CharField(widget=forms.CheckBoxSelectMultiple(choices=LANGUAGE_LIST)) class Meta: model = Person it is ok. but how can i search persons for languages like "get persons who knows turkish and english" in the database (MySQL) record "languages" column seen like "[u'1', u'2']". but i want search persons like this: persons = Person.objects.filter(languages__in=request.POST.getlist('languages'))

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  • Executing procedural queries in perl

    - by KalpaG
    I have a query like this set @valid_total:=0; set @invalid_total:=0; select week as weekno, measured_week,project_id as project, role_category_id as role_category, valid_count,valid_tickets, (@valid_total := @valid_total + valid_count) as valid_total, invalid_count,invalid_tickets, (@invalid_total := @invalid_total + invalid_count) as invalid_total from metric_fault_bug_project where measured_week = yearweek(curdate()) and role_category_id = 1 and project_id = 11; it executes fine in heidi (MySQL client) but when it comes to perl, it gives me this error DBD::mysql::st execute failed: You have an error in your SQL syntax; check the m anual that corresponds to your MySQL server version for the right syntax to use near ':=0; set :=0; select week as weekno, measured_week,project_id as project' at line 1 at D:\Mx\scripts\test.pl line 35. Can't execute SQL statement: You have an error in your SQL syntax; check the man ual that corresponds to your MySQL server version for the right syntax to use ne ar ':=0; set :=0; select week as weekno, measured_week,project_id as project' at line 1 The problem seem to be in the set @valid_total := 0; line. I am fairly new to Perl. Can anyone help? this is the complete perl code #!/usr/bin/perl #use lib '/x01/home/kalpag/libs'; use DBI; use strict; use warnings; my $sid = 'issues'; my $user = 'root'; my $passwd = 'kalpa'; my $connection = "DBI:mysql:database=$sid;host=localhost"; my $dbhh = DBI->connect( $connection, $user, $passwd) || die "Database connection not made: $DBI::errstr"; my $sql_query = 'set @valid_total:=0; set @invalid_total:=0; select week as weekno, measured_week,project_id, role_category_id as role_category, valid_count,valid_tickets, (@valid_total := @valid_total + valid_count) as valid_total, invalid_count,invalid_tickets, (@invalid_total := @invalid_total + invalid_count) as invalid_total from metric_fault_bug_project where measured_week = yearweek(curdate()) and role_category_id = 1 and project_id = 11'; my $sth = $dbhh->prepare($sql_query) or die "Can't prepare SQL statement: $DBI::errstr\n"; $sth->execute() or die "Can't execute SQL statement: $DBI::errstr\n"; while ( my @memory = $sth->fetchrow() ) { print "@memory \n"; }

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  • SQl queries searching by date range

    - by tecno
    Hi, I have a table in an Access 2007 database, all fields are of type text. Can the following be done using the where clause. If so how? SELECT * from Table1 WHERE (ColumnDate is between 26th and 19th of march 2010) SELECT * from Table1 WHERE (ColumnAge is between 25 and 40) The usual < <= operators dont seem to work. Thanks,

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  • mySQL - One large query vs Ajax indivdual queries

    - by Mark
    Hi guys, I guess no one will have a definative answer to this but considered predictions would be appriciated. I am in the process of developing a mySQL database for a web application and my question is: Is it more efficient to make a single query that returns a single row using AJAX or To request 100 - 700 rows when the user will likely only ever use the results of two or three? Really I am asking what is heavier for the server 2-3 requests with one result or 1 request with 100 - 700 results? Thanks, Mark

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  • Run SQL Queries on DataTables, or similar, in .Net, without an RDBMS

    - by FastAl
    I'd like to have a dataset or datatables, and be able to run SQL statements on them, without using any external RDBMS. For Example, to take take 2 datatables in a dataset and just join them outright with a SQL statement and Where clause, the result being a new datatable? For example if I have 2 datatables, named People and Addresses in a dataset (that I built using code, not getting from a database .. pardon the old fashioned Join syntax): dim dtJoined as DataTable = MyDataSet.RunSQLQuery ("Select * from People, Orders Where People.PersonID=Orders.OrdereID") Thanks

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  • exploratory SPARQL queries?

    - by significance
    whenever i start using sql i tend to throw a couple of exploratory statements at the database in order to understand what is avaliable, and what form the data takes. eg. show tables describe table select * from table could anyone help me understand the way to complete a similar exploration of an rdf datastore using a SPARQL endpoint? Thanks :)

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