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  • Which workaround to use for the following SQL deadlock?

    - by Marko
    I found a SQL deadlock scenario in my application during concurrency. I belive that the two statements that cause the deadlock are (note - I'm using LINQ2SQL and DataContext.ExecuteCommand(), that's where this.studioId.ToString() comes into play): exec sp_executesql N'INSERT INTO HQ.dbo.SynchronizingRows ([StudioId], [UpdatedRowId]) SELECT @p0, [t0].[Id] FROM [dbo].[UpdatedRows] AS [t0] WHERE NOT (EXISTS( SELECT NULL AS [EMPTY] FROM [dbo].[ReceivedUpdatedRows] AS [t1] WHERE ([t1].[StudioId] = @p0) AND ([t1].[UpdatedRowId] = [t0].[Id]) ))',N'@p0 uniqueidentifier',@p0='" + this.studioId.ToString() + "'; and exec sp_executesql N'INSERT INTO HQ.dbo.ReceivedUpdatedRows ([UpdatedRowId], [StudioId], [ReceiveDateTime]) SELECT [t0].[UpdatedRowId], @p0, GETDATE() FROM [dbo].[SynchronizingRows] AS [t0] WHERE ([t0].[StudioId] = @p0)',N'@p0 uniqueidentifier',@p0='" + this.studioId.ToString() + "'; The basic logic of my (client-server) application is this: Every time someone inserts or updates a row on the server side, I also insert a row into the table UpdatedRows, specifying the RowId of the modified row. When a client tries to synchronize data, it first copies all of the rows in the UpdatedRows table, that don't contain a reference row for the specific client in the table ReceivedUpdatedRows, to the table SynchronizingRows (the first statement taking part in the deadlock). Afterwards, during the synchronization I look for modified rows via lookup of the SynchronizingRows table. This step is required, otherwise if someone inserts new rows or modifies rows on the server side during synchronization I will miss them and won't get them during the next synchronization (explanation scenario to long to write here...). Once synchronization is complete, I insert rows to the ReceivedUpdatedRows table specifying that this client has received the UpdatedRows contained in the SynchronizingRows table (the second statement taking part in the deadlock). Finally I delete all rows from the SynchronizingRows table that belong to the current client. The way I see it, the deadlock is occuring on tables SynchronizingRows (abbreviation SR) and ReceivedUpdatedRows (abbreviation RUR) during steps 2 and 3 (one client is in step 2 and is inserting into SR and selecting from RUR; while another client is in step 3 inserting into RUR and selecting from SR). I googled a bit about SQL deadlocks and came to a conclusion that I have three options. Inorder to make a decision I need more input about each option/workaround: Workaround 1: The first advice given on the web about SQL deadlocks - restructure tables/queries so that deadlocks don't happen in the first place. Only problem with this is that with my IQ I don't see a way to do the synchronization logic any differently. If someone wishes to dwelve deeper into my current synchronization logic, how and why it is set up the way it is, I'll post a link for the explanation. Perhaps, with the help of someone smarter than me, it's possible to create a logic that is deadlock free. Workaround 2: The second most common advice seems to be the use of WITH(NOLOCK) hint. The problem with this is that NOLOCK might miss or duplicate some rows. Duplication is not a problem, but missing rows is catastrophic! Another option is the WITH(READPAST) hint. On the face of it, this seems to be a perfect solution. I really don't care about rows that other clients are inserting/modifying, because each row belongs only to a specific client, so I may very well skip locked rows. But the MSDN documentaion makes me a bit worried - "When READPAST is specified, both row-level and page-level locks are skipped". As I said, row-level locks would not be a problem, but page-level locks may very well be, since a page might contain rows that belong to multiple clients (including the current one). While there are lots of blog posts specifically mentioning that NOLOCK might miss rows, there seems to be none about READPAST (never) missing rows. This makes me skeptical and nervous to implement it, since there is no easy way to test it (implementing would be a piece of cake, just pop WITH(READPAST) into both statements SELECT clause and job done). Can someone confirm whether the READPAST hint can miss rows? Workaround 3: The final option is to use ALLOW_SNAPSHOT_ISOLATION and READ_COMMITED_SNAPSHOT. This would seem to be the only option to work 100% - at least I can't find any information that would contradict with it. But it is a little bit trickier to setup (I don't care much about the performance hit), because I'm using LINQ. Off the top of my head I probably need to manually open a SQL connection and pass it to the LINQ2SQL DataContext, etc... I haven't looked into the specifics very deeply. Mostly I would prefer option 2 if somone could only reassure me that READPAST will never miss rows concerning the current client (as I said before, each client has and only ever deals with it's own set of rows). Otherwise I'll likely have to implement option 3, since option 1 is probably impossible... I'll post the table definitions for the three tables as well, just in case: CREATE TABLE [dbo].[UpdatedRows]( [Id] [uniqueidentifier] NOT NULL ROWGUIDCOL DEFAULT NEWSEQUENTIALID() PRIMARY KEY CLUSTERED, [RowId] [uniqueidentifier] NOT NULL, [UpdateDateTime] [datetime] NOT NULL, ) ON [PRIMARY] GO CREATE NONCLUSTERED INDEX IX_RowId ON dbo.UpdatedRows ([RowId] ASC) WITH (STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] GO CREATE TABLE [dbo].[ReceivedUpdatedRows]( [Id] [uniqueidentifier] NOT NULL ROWGUIDCOL DEFAULT NEWSEQUENTIALID() PRIMARY KEY NONCLUSTERED, [UpdatedRowId] [uniqueidentifier] NOT NULL REFERENCES [dbo].[UpdatedRows] ([Id]), [StudioId] [uniqueidentifier] NOT NULL REFERENCES, [ReceiveDateTime] [datetime] NOT NULL, ) ON [PRIMARY] GO CREATE CLUSTERED INDEX IX_Studios ON dbo.ReceivedUpdatedRows ([StudioId] ASC) WITH (STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] GO CREATE TABLE [dbo].[SynchronizingRows]( [StudioId] [uniqueidentifier] NOT NULL [UpdatedRowId] [uniqueidentifier] NOT NULL REFERENCES [dbo].[UpdatedRows] ([Id]) PRIMARY KEY CLUSTERED ([StudioId], [UpdatedRowId]) ) ON [PRIMARY] GO PS! Studio = Client. PS2! I just noticed that the index definitions have ALLOW_PAGE_LOCK=ON. If I would turn it off, would that make any difference to READPAST? Are there any negative downsides for turning it off?

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  • Oracle 10g multiple DELETE statements

    - by bmw0128
    I'm building a dml file that first deletes records that may be in the table, then inserts records. Example: DELETE from foo where field1='bar'; DELETE from foo where fields1='bazz'; INSERT ALL INTO foo(field1, field2) values ('bar', 'x') INTO foo(field1, field2) values ('bazz', 'y') SELECT * from DUAL; When I run the insert statement by itself, it runs fine. When I run the deletes, only the last delete runs. Also, it seems to be necessary to end the multiple insert with the select, is that so? If so, why is that necessary? In the past, when using MySQL, I could just list multiple delete and insert statements, all individually ending with a semicolon, and it would run fine.

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  • From xcode not able to execute DISTINCT keyword for sqlite

    - by mac
    -(void) readProductsFromDatabase { // Setup the database object sqlite3 *database; // Init the animals Array products = [[NSMutableArray alloc] init]; // Open the database from the users filessytem if(sqlite3_open([databasePath UTF8String], &database) == SQLITE_OK) { NSLog(@"db opened"); // Setup the SQL Statement and compile it for faster access const char *sqlStatement = "SELECT DISTINCT productname FROM iphone "; sqlite3_stmt *compiledStatement; if(sqlite3_prepare_v2(database, sqlStatement, -1, &compiledStatement, NULL) == SQLITE_OK) { // Loop through the results and add them to the feeds array while(sqlite3_step(compiledStatement) == SQLITE_ROW) { NSLog(@"inside sqlite3 prepare"); // Read the data from the result row NSString *aName = [NSString stringWithUTF8String:(char *)sqlite3_column_text(compiledStatement, 2)]; } } // Release the compiled statement from memory sqlite3_finalize(compiledStatement); } sqlite3_close(database); } My problem is const char *sqlStatement = "SELECT DISTINCT productname FROM iphone "; This line not executing ,i am using sqlite3, thanks in advance,

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  • problem while checking second check checkbox checked.

    - by kumar
    $('#nextpage').click(function() { $('#Details input[type=checkbox]').each( function() { if( $(this).attr('checked') ) { $("#tabs").tabs('enable', 3).tabs('select', 3); } else { $().ShowDialog('please select atleast one'); } }); }); <fieldset> <legend>information</legend> <input type="checkbox"> <label>ID#: <span><%=(null != a) ? Model.ID: 0%></span></label> <label>Name:<span><%=(null != a) ? Model.Name: null%></span></label> </fieldset> this filedset is for multiple users.. that is on the same page there are multiple fiedsetsfor multiple users.. how to handle those things.. thanks

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  • Making GridView Respond to 2 Drop Down Lists

    - by raziiq
    Hi there. I have got 2 Drop Down Lists on my Form and 1 GridView. I want GridView to display the data according to selection from the Drop Down Lists. For Example, One Drop Down List contains Names and other contains Dates. Both the Drop Down Lists can post back. So if i select a name from 1st Drop Down list, the Grid View should show all the results according to that Name. Similarly if i select the Date from the other Drop Down List , the Grid View should show the results according to the dates. But i cant figure out as how to bind Grid View to respond to 2 Drop Down List. BTW i am binding both the Drop Down Lists and the Grid View to the DataSource Objects, which is getting data from the database. Any Suggestions??

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  • Use content of fieldnames in query..

    - by rokdd
    Hi, i have three mysql tables: Table 456 id | binder | property1 1 | b | hello 2 | b | goodbye 3 | a | bonjour Table binder id | binder | tableid1 | tableid2 1 | a | 23 | 456 2 | b | 21 | 456 3 | c | 45 | 42 Table 21 id | property1 | data.. 1 | goodbye | data about goodbye.. 2 | ciao | data about ciao.. So first i want to select in binder the binder i need to get the tablesname where data is stored. So i need to select table by a fieldname in this case the fieldname is tableid1 and would have the content 21 so that i have to look in 21. AND it should be property 1 from table 456 and table 21 the same... i am using php and already tried with union and subquerys but it seems that i am to silly to prepare such query!

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  • Does having a longer string in a SQL Like expression allow hinder or help query executing speed?

    - by Allain Lalonde
    I have a db query that'll cause a full table scan using a like clause and came upon a question I was curious about... Which of the following should run faster in Mysql or would they both run at the same speed? Benchmarking might answer it in my case, but I'd like to know the why of the answer. The column being filtered contains a couple thousand characters if that's important. SELECT * FROM users WHERE data LIKE '%=12345%' or SELECT * FROM users WHERE data LIKE '%proileId=12345%' I can come up for reasons why each of these might out perform the other, but I'm curious to know the logic.

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  • How do you optimize database performance when providing results for autocomplete/iterative search?

    - by Howiecamp
    Note: In this question I'm using the term "autocomplete" (or "iterative search") to refer to returning search-as-you-type results, e.g. like Google Search gives you. Also my question is not specific to web applications vs. fat client apps. How are SQL SELECT queries normally constructed to provide decent performance for this type of query, especially over arbitrarily large data sets? In the case where the search will only query based on the first n characters (easiest case) am I still issuing a new SELECT result FROM sometable WHERE entry LIKE... on each keypress. Even with various forms of caching this seems like it might result in poor performance. In cases where you want your search string to return results with prefix matches, substring matches, etc. it's an even more difficult problem. Looking at a case of searching a list of contacts, you might return results that match FirstName + LastName, LastName + FirstName, or any other substring.

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  • How to pass a variable inside a jquery fonction $.each($("abc")...?

    - by Rock
    I'm trying to iterate a bunch of SELECT OPTION html drop-down fields and from the ones that are NOT empty, take the values and add a hidden field for a PAYPAL shopping cart. My problem is that for some reason, the variable "curitem" is not passed inside the each function and I can't add the hidden field like they should. All I get is "NaN" or "undefined". What PAYPAL expect is : item_name_1, item_name_2, etc. All numbers must iterate by +1. How can I do this? Thanks a bunch in advance var curitem; $.each($("select"), function(index, item) { var attname = $(this).attr("name"); var nom = $(this).attr("data-nom"); var prix = $(this).attr("data-val"); var partname = attname.substring(0, 1); var qte = $(this).val(); // i want all my <select option> items that the NAME start with "q" AND have a value selected if (partname == "q" && isNaN(qte) == false && qte > 0) { // item name var inp2 = document.createElement("input"); inp2.setAttribute("type", "hidden"); inp2.setAttribute("id", "item_name_"+curitem); inp2.setAttribute("name", "item_name_"+curitem); inp2.setAttribute("value", nom); // amount var inp3 = document.createElement("input"); inp3.setAttribute("type", "hidden"); inp3.setAttribute("id", "amount_"+curitem); inp3.setAttribute("name", "amount_"+curitem); inp3.setAttribute("value", prix); // qty var inp4 = document.createElement("input"); inp4.setAttribute("type", "hidden"); inp4.setAttribute("id", "quantity_"+curitem); inp4.setAttribute("name", "quantity_"+curitem); inp4.setAttribute("value", qte); // add hidden fields to form document.getElementById('payPalForm').appendChild(inp2); document.getElementById('payPalForm').appendChild(inp3); document.getElementById('payPalForm').appendChild(inp4); // item number curitem = curitem + 1; } });

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  • Eliminate duplicates in SQL query

    - by ewdef
    i have a table with 6 fields. the columns are ID, new_id price,title,Img,Active. I have datawhich is duplicated for the price column. When I do a select i want to show only distinct rows where new_id is not the same. e.g.- ID New_ID Price Title Img Active 1 1 20.00 PA-1 0X4... 1 2 1 10.00 PA-10 0X4... 1 3 3 20.00 PA-11 0X4... 1 4 4 30.00 PA-5 0X4... 1 5 9 20.00 PA-99A 0X4... 1 6 3 50.00 PA-55 0X4... 1 When the select statement runs, only rows with ID (1,4,9,6) should show. Reason being the new_ID with the higher price should show up. How can i do this?

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  • MySQL, delete and index hint

    - by Manuel Darveau
    I have to delete about 10K rows from a table that has more than 100 million rows based on some criteria. When I execute the query, it takes about 5 minutes. I ran an explain plan (the delete query converted to select * since MySQL does not support explain delete) and found that MySQL uses the wrong index. My question is: is there any way to tell MySQL which index to use during delete? If not, what ca I do? Select to temp table then delete from temp table? Thank you!

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  • In cocos2D how to write a selector for a sprite.

    - by srikanth rongali
    Hello, I got problem in cocos2D application. I have a sprite and text in one screen. The text should be able to move up/down when we swipe. And when we select on the sprite it should take to next scene. So, both should have the istouchEnabled to YES. But text should take the touchesMoved and sprite should take touchesEnded. But my problem is either one is working. If am able to swipe the text, I am not able to select the sprite.( touchesEnded for sprite is not called). Please guide me, I am stuck here.

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  • XPath selection from path in XML content

    - by Wayne Robinson
    I have the following XML: <root> <name>The name</name> <long> <path> <value>Some Value</value> </path> </long> <field>/root/name</field> <field>/root/long/path/value</field> </root> and I want to select these paths in the field tags however, when I try the following: <xsl:value-of select="/root/field[1]" /> all I get is the text value of the field. Is there a way of selecting the correct node from those values?

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  • I need to simplify a MySQL sub query for performance - please help

    - by Richard
    I have the following query which is takin 3 seconds on a table of 1500 rows, does someone know how to simplify it? SELECT dealers.name, dealers.companyName, dealer_accounts.balance FROM dealers INNER JOIN dealer_accounts ON dealers.id = dealer_accounts.dealer_id WHERE dealer_accounts.id = ( SELECT id FROM dealer_accounts WHERE dealer_accounts.dealer_id = dealers.id AND dealer_accounts.date < '2010-03-30' ORDER BY dealer_accounts.date DESC, dealer_accounts.id DESC LIMIT 1 ) ORDER BY dealers.name I need the latest dealer_accounts record for each dealer by a certain date with the join on the dealer_id field on the dealer_accounts table. This really should be simple, I don't know why I am struggling to find something.

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  • Oracle function always returning null

    - by JavaRocky
    I can't get this function to behave as i desire. Can anyone point out why it always returns null instead of CURRENT_TIMESTAMP? CREATE OR REPLACE FUNCTION nowts RETURN TIMESTAMP IS vTimestamp TIMESTAMP; BEGIN SELECT type_date INTO vTimestamp FROM param_table WHERE param_table = 3 AND exists ( SELECT * FROM param_table WHERE param_table = 2 ); IF vTimestamp IS NULL THEN vTimestamp := CURRENT_TIMESTAMP; END IF; return vTimestamp; END nowts; Right now there is nothing in the table named param_table.

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  • Performing LINQ Self Join

    - by senfo
    I'm not getting the results I want for a query I'm writing in LINQ using the following: var config = (from ic in repository.Fetch() join oc in repository.Fetch() on ic.Slot equals oc.Slot where ic.Description == "Input" && oc.Description == "Output" select new Config { InputOid = ic.Oid, OutputOid = oc.Oid }).Distinct(); The following SQL returns 53 rows (which is correct), but the above LINQ returns 96 rows: SELECT DISTINCT ic.Oid AS InputOid, oc.Oid AS OutputOid FROM dbo.Config AS ic INNER JOIN dbo.Config AS oc ON ic.Slot = oc.Slot WHERE ic.Description = 'Input' AND oc.Description = 'Output' How would I replicate the above SQL in a LINQ query? Update: I don't think it matters, but I'm working with LINQ to Entities 4.0.

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  • Display different xsl:attribute depending on the code

    - by Johann
    Dear All, I have the following xsl code in an xsl document <A target="_blank" style="text-decoration=none"> <xsl:attribute name="href">viewdoc.aspx?doc=<xsl:value-of select="URLFilePath"/>&amp;mode=inline</xsl:attribute> <xsl:attribute name="prefix"><xsl:value-of select="FileName"/>: </xsl:attribute> <IMG src="images/word_small.gif" border="0"/> </A> and in the code-behind I am doing this newItemNode = xmlDocument.CreateElement("URLFilePath") newItemNode.InnerText = correctedPath xmlItemNode.ParentNode.AppendChild(newItemNode) Now that works fine for word documents. However I need a way in code to check the extension of the file, and display the correct Image and xsl:attribute depending on the If statement. So the If statement will be like this:- If correctedPath.ToLower.Contains(".doc") Then //display the word icon and attributes Else //display the excel icon and attributes End If Can you please give me some tips and help on how I can achieve this? Thanks

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  • Mysql Limit column value repetition N times

    - by Paper-bat
    Hi at all, is my first question here, so be patient ^^ I'll go directly to problem, I have two table Customer (idCustomer, ecc.. ecc..) Comment (idCustomer, idComment, ecc.. ecc..) obviosly the two table are joined togheter, for example SELECT * FROM Comment AS co JOIN Customer AS cu ON cu.idCustomer = co.idCustomer With this I select all comment from that table associated with is Customer, but now I wanna limit the number of Comment by 2 max Comment per Customer. The first thing I see is to use 'GROUP BY cu.idCustomer' but it limit only 1 Comment per Customer, but I wanna 2 Comment per Customer.. how now to proceed?

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  • MYSQL -Incorrect Syntax

    - by user1854392
    WHILE x > 1 DO SET x = x - 1; SET totalTime = SELECT CONCAT(FLOOR(HOUR(TIMEDIFF(end_time,start_time)) / 24), ' days ', MOD(HOUR(TIMEDIFF(end_time,start_time)), 24), ' hrs ', MINUTE(TIMEDIFF(end_time,start_time)), ' minutes ') AS total_Time I don't see why I am having a syntax error? It is part of a bigger procedure but is pointing to this aas being incorrect Error message: SQL Error (1064): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'SELECT CONCAT(FLOOR(HOUR(TIMEDIFF(end_time,start_time)) / 24,' days',' at line 11 and totalTime is declared as a VARCHAR(50)

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  • Time diff calculations where date and time are in seperate columns

    - by pedalpete
    I've got a query where I'm trying to get the hours in duration (eg 6.5 hours) between two different times. In my database, time and date are held in different fields so I can efficiently query on just a startDate, or endDate as I never query specifically on time. My query looks like this SELECT COUNT(*), IFNULL(SUM(TIMEDIFF(endTime,startTime)),0) FROM events WHERE user=18 Sometimes an event will go overnight, so the difference between times needs to take into account the differences between the dates as well. I've been trying SELECT COUNT(*), IFNULL(SUM(TIMEDIFF(CONCAT(endDate,' ',endTime),CONCAT(startDate,' ',startTime))),0) FROM events WHERE user=18 Unfortunately I only get errors when I do this, and I can't seem to combine the two fields into a single timestamp.

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  • How to reflect over T to build an expression tree for a query?

    - by Alex
    Hi all, I'm trying to build a generic class to work with entities from EF. This class talks to repositories, but it's this class that creates the expressions sent to the repositories. Anyway, I'm just trying to implement one virtual method that will act as a base for common querying. Specifically, it will accept a an int and it only needs to perform a query over the primary key of the entity in question. I've been screwing around with it and I've built a reflection which may or may not work. I say that because I get a NotSupportedException with a message of LINQ to Entities does not recognize the method 'System.Object GetValue(System.Object, System.Object[])' method, and this method cannot be translated into a store expression. So then I tried another approach and it produced the same exception but with the error of The LINQ expression node type 'ArrayIndex' is not supported in LINQ to Entities. I know it's because EF will not parse the expression the way L2S will. Anyway, I'm hopping someone with a bit more experience can point me into the right direction on this. I'm posting the entire class with both attempts I've made. public class Provider<T> where T : class { protected readonly Repository<T> Repository = null; private readonly string TEntityName = typeof(T).Name; [Inject] public Provider( Repository<T> Repository) { this.Repository = Repository; } public virtual void Add( T TEntity) { this.Repository.Insert(TEntity); } public virtual T Get( int PrimaryKey) { // The LINQ expression node type 'ArrayIndex' is not supported in // LINQ to Entities. return this.Repository.Select( t => (((int)(t as EntityObject).EntityKey.EntityKeyValues[0].Value) == PrimaryKey)).Single(); // LINQ to Entities does not recognize the method // 'System.Object GetValue(System.Object, System.Object[])' method, // and this method cannot be translated into a store expression. return this.Repository.Select( t => (((int)t.GetType().GetProperties().Single( p => (p.Name == (this.TEntityName + "Id"))).GetValue(t, null)) == PrimaryKey)).Single(); } public virtual IList<T> GetAll() { return this.Repository.Select().ToList(); } protected virtual void Save() { this.Repository.Update(); } }

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  • Adding a clustered index to a SQL table: what dangers exist for a live production system?

    - by MoSlo
    Right, keep in mind i need to describe this by abstracting all possible confidential info: I've been put in charge of a 10-year old transactional system of which the majority business logic is implemented at database level (triggers, stored procedures etc). Win2000 server, MSSQL 2000 Enterprise. No immediate plans for replacing/updating the system are being considered :( The core process is a program that executes transactions - specifically, it executes a stored procedure with various parameters, lets call it sp_ProcessTrans. The program executes the stored procedure at asynchronous intervals. By itself, things work fine. But there are 30 instances of this program on remotely located workstations, all of them asynchronously executing sp_ProcessTrans and then retrieving data from the SQL server (execution is pretty regular - ranging 0 to 60 times a minute, depending on what items the program instance is responsible for) . Performance of the system has dropped considerably with 10 yrs of data growth: the reason is the deadlocks and specifically deadlock wait times. The deadlock is on the Employee table. I have discovered: In sp_ProcessTrans' execution, it selects from an Employee table 7 times (dont ask) The select is done on a field that is NOT the primary key No index exists on this field. Thus a table scan is performed. 7 times. per transaction So the reason for deadlocks is clear. I created a non-unique ordered clustered index on the field (field looks good, almost unique, NUM(7), very rarely changes). Immediate improvement in the test environment. The problem is that i cannot simulate the deadlocks in a test environment (I'd need 30 workstations; i'd need to simulate 'realistic' activity on those stations, so visualization is out). I need to know if i must schedule downtime. Creating an index shouldn't be a risky operation for MSSQL, but is there any danger (data corruption in transactions/select statements/extra wait time etc) to create this field index on the production database while the transactions are still taking place? (although i can select a time when transactions are fairly quiet through the 30 stations) Are there any hidden dangers i'm not seeing (not looking forward to needing to restore the DB if something goes wrong, restoring would take a lot of time with 10yrs of data).

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  • How do stream rows from a MSSQL table into a .NET app, in 10000 row chunks?

    - by Gravitas
    I have a table with 300 million rows in Microsoft SQL Server 2008 R2. There is a clustered index on the date column [DataDate] which means that the entire table is ordered by the date column. How do I stream out the data from this table, into my .NET application, in 10000 row chunks? Environment: Using C#. Have to be able to pause the data stream at any point, to allow the client to process the rows. Unfortunately, cannot use a select * from as this will select the entire table (its 50GB - it won't fit into memory).

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  • Doctrine2: Filtering by ManToMany Association

    - by Shroder
    I want to retrieve a collection of objects based on what they are associated to. For example, by a category. This would be a Many to Many relationship. I've been able to achieve that with MEMBER OF, however I need to pass in an array of IDs, opposed to one at a time. I see there is an "IN ()", but it seems to require a subquery, which I would like to avoid. MEMBER OF example: SELECT o FROM Entity\Object1 o WHERE 'CATEGORY_CODE' MEMBER OF o.categories (Edit) This is what I would like to do, but perhaps I'm misunderstanding how entities work in DQL: SELECT o FROM Entity\Object1 o WHERE o.categories.Id IN (id, id, id)

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