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• SQL Azure vs. SQL Server

  - by guybarrette

  If you’d like to know the differences between SQL Server and SQL Azure, check this white paper. This FAQ is also interesting. var addthis_pub="guybarrette";

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• HTTP Push from SQL Server Comet SQL

  Article provides example solution for presenting data in "real-time" from Microsoft SQL Server in HTML browser. Article presents how to implement Comet functionality in ASP.NET and how to connect Comet with Query Notification from SQL Server....Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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• Post SQL 2008 R2 Launch Thurs 15th London - UK SQL Server User Group is having a Social Event @ the

  - by tonyrogerson

  The UK SQL Server User Group is organising a Social event for SQL and SQL Server professionals, the event will be held after the SQL Server 2008 R2 launch event and is a short walk from that venue. See site for more information: http://sqlserverfaq.com/events/222/Social-for-SQL-and-SQL-Server-professionals-SQL-quiz-meet-your-peers-ask-the-group-Q-A.aspx We are putting some light bites on, if you are coming then do let us know through the site. Neil Hambly who is the London UK SQL Server User Group...(read more)

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• Non-English Character Display in Oracle SQL Developer

  - by thatjeffsmith

  I get a variation on this question at least once a week, if not more frequently. I’m from Israel, and the language on the databases is Hebrew. When I use the old and deprecated SQL*Plus (windows rich client) I can see the hebrew clearly, when I use the latest SQL Developer, I get gibberish. This question appears on the forums about every week or so as well. So what’s the deal? Well, it starts with a basic misunderstanding of NLS Client parameters. These should accurately reflect the language and locality setup on your LOCAL machine. DO NOT COPY what’s set in the database. The these parameters work together with the database so that information can be transferred back and forth correctly. Having the wrong NLS parameters locally can be bad. [ORACLE DOCS]Setting the NLS_LANG parameter properly is essential to proper data conversion. The character set that is specified by the NLS_LANG parameter should reflect the setting for the client operating system. Setting NLS_LANG correctly enables proper conversion from the client operating system character encoding to the database character set. When these settings are the same, Oracle Database assumes that the data being sent or received is encoded in the same character set as the database character set, so character set validation or conversion may not be performed. This can lead to corrupt data if conversions are necessary. OK, so what are you supposed to do? Set the Font! 9 times out of 10, this preference fixes the problem with display issues. Make sure you set a Font that supports the characters you’re trying to display. It’s as simple as that. This preference defines the font used to display characters in the editors and the data grids. If you have it set to a font that doesn’t have Hebrew character support – you’re not going to see Hebrew in SQL Developer. A few years ago…wow, like 15 years ago, I learned that the Tohama Font is pretty Unicode-friendly. Bad Font Selection A Font that’s not non-English friendly Good Font Selection Exact same text, except rendered with the Tahoma font Summary Having problems seeing non-English text in SQL Developer? Check the font! And do not start messing with NLS parameters without talking to your DBA first.

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• SQL Server CTE Basics

  The CTE was introduced into standard SQL in order to simplify various classes of SQL Queries for which a derived table just wasn't suitable. For some reason, it can be difficult to grasp the techniques of using it. Well, that's before Rob Sheldon explained it all so clearly for us.

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• Idera Compliance Manager 3.5 and SQL Server 2012 Release Candidate

  Unlike most conventional database auditing solutions, SQL Compliance Manager places a blanket over data access with real-time auditing. Clients can pinpoint any malicious intent with sensitive column auditing. This feature gives specifics as to who has accessed information located within an audited table's sensitive columns. With transaction status auditing, database administrators can detect suspicious activity by auditing the status of transactions that execute DML statements on an audited database with the help of rollbacks and save-points. In addition, SQL Compliance Manager lives up t...

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• SQL: empty string vs NULL value

  - by Jacek Prucia

  I know this subject is a bit controversial and there are a lot of various articles/opinions floating around the internet. Unfortunatelly, most of them assume the person doesn't know what the difference between NULL and empty string is. So they tell stories about surprising results with joins/aggregates and generally do a bit more advanced SQL lessons. By doing this, they absolutely miss the whole point and are therefore useless for me. So hopefully this question and all answers will move subject a bit forward. Let's suppose I have a table with personal information (name, birth, etc) where one of the columns is an email address with varchar type. We assume that for some reason some people might not want to provide an email address. When inserting such data (without email) into the table, there are two available choices: set cell to NULL or set it to empty string (''). Let's assume that I'm aware of all the technical implications of choosing one solution over another and I can create correct SQL queries for either scenario. The problem is even when both values differ on the technical level, they are exactly the same on logical level. After looking at NULL and '' I came to a single conclusion: I don't know email address of the guy. Also no matter how hard i tried, I was not able to sent an e-mail using either NULL or empty string, so apparently most SMTP servers out there agree with my logic. So i tend to use NULL where i don't know the value and consider empty string a bad thing. After some intense discussions with colleagues i came with two questions: am I right in assuming that using empty string for an unknown value is causing a database to "lie" about the facts? To be more precise: using SQL's idea of what is value and what is not, I might come to conclusion: we have e-mail address, just by finding out it is not null. But then later on, when trying to send e-mail I'll come to contradictory conclusion: no, we don't have e-mail address, that @!#$ Database must have been lying! Is there any logical scenario in which an empty string '' could be such a good carrier of important information (besides value and no value), which would be troublesome/inefficient to store by any other way (like additional column). I've seen many posts claiming that sometimes it's good to use empty string along with real values and NULLs, but so far haven't seen a scenario that would be logical (in terms of SQL/DB design). P.S. Some people will be tempted to answer, that it is just a matter of personal taste. I don't agree. To me it is a design decision with important consequences. So i'd like to see answers where opion about this is backed by some logical and/or technical reasons.

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• SQL Server APPLY Basics

  One of the most interesting additions to SQL Server syntax in SQL Server 2005 was the APPLY operator. It allows several queries that were previously impossible. It is surprisingly difficult to find a simple explanation of what APPLY actually does. Rob Sheldon is the specialist in simple explanations, so we asked him.

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• Oracle to SQL Server: Crossing the Great Divide, Part 2

  A well-known Oracle expert records faithfully his struggles with the unfamiliar : SQL Server. He now sets himself the task of creating a table with a million rows of random data. As one might expect, it is the lack of familiarity with the workarounds and tricks of SQL Server that trips him up. His journey brings us fresh insights, and a glimpse at the alternative-universe of Oracle.

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• Alternative to TOP in SQL Server and Oracle.

  SELECT TOP 5 * FROM EMP ORDER BY SALARY;above query works in SQL Server. This returns top 5 employees. The problem with this query is it doesn't work with Oracle.In Oracle you would need to write the query as follows.SELECT * FROM EMP WHERE ROWNUMIf you are looking for a query which runs in both Oracle and SQL Server. Please use below one.select * from (SELECT row_number() over( ORDER by SALARY) as rank, EMP.* FROM EMP) s1 where s1.rank span.fullpost {display:none;}

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• Init Replication From Backup

  One of the great features with SQL Replication is the ability to initialize a subscription from backup instead of from a snapshot. The official use for this is to take a database backup and restore it to a subscriber then replicate any additional changes to the backup. New! SQL Monitor 3.0 Red Gate's multi-server performance monitoring and alerting tool gets results from Day One.Simple to install and easy to use – download a free trial today.

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• Advice on database design / SQL for retrieving data with chronological order

  - by Remnant

  I am creating a database that will help keep track of which employees have been on a certain training course. I would like to get some guidance on the best way to design the database. Specifically, each employee must attend the training course each year and my database needs to keep a history of all the dates on which they have attend the course in the past. The end user will use the software as a planning tool to help them book future course dates for employees. When they select a given employee they will see: (a) Last attendance date (b) Projected future attendance date(i.e. last attendance date + 1 calendar year) In terms of my database, any given employee may have multiple past course attendance dates: EmpName AttandanceDate Joe Bloggs 1st Jan 2007 Joe Bloggs 4th Jan 2008 Joe Bloggs 3rd Jan 2009 Joe Bloggs 8th Jan 2010 My question is what is the best way to set up the database to make it easy to retrieve the most recent course attendance date? In the example above, the most recent would be 8th Jan 2010. Is there a good way to use SQL to sort by date and pick the MAX date? My other idea was to add a column called ‘MostRecent’ and just set this to TRUE. EmpName AttandanceDate MostRecent Joe Bloggs 1st Jan 2007 False Joe Bloggs 4th Jan 2008 False Joe Bloggs 3rd Jan 2009 False Joe Bloggs 8th Jan 2010 True I wondered if this would simplify the SQL i.e. SELECT Joe Bloggs WHERE MostRecent = ‘TRUE’ Also, when the user updates a given employee’s attendance record (i.e. with latest attendance date) I could use SQL to: Search for the employee and set the MostRecent value to FALSE Add a new record with MostRecent set to TRUE? Would anybody recommended either method over the other? Or do you have a completely different way of solving this problem?

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• vb6 ADODB connection string to sql server 2008

  - by phill

  I recently migrated a database from sql server 2005 to 2008 on windows server 2008. Clients connect fine from their XP machines and so does the SQL Management Studio 2008. I have also tested a remote connection using LINQPad which worked fine. However on my VB6 app, the connection string seems to give me problems. Any ideas what I'm doing wrong? Dim strUserName As String Dim strPassword As String Dim sProc As String sProc = "Class_clsAdoFnx_Initialize" Me.DatabaseName = "db_app" 'Connect to SQL Server strUserName = "admin" strPassword = "mudslinger" Set cSQLConn = New ADODB.Connection '**Original connection String 'cSQLConn.CommandTimeout = 0 'cSQLConn.ConnectionString = " PROVIDER=SQLOLEDB" & _ ' ";SERVER=NET-BRAIN" & _ ' ";UID=" & strUserName & _ ' ";PWD=" & strPassword & _ ' ";DATABASE=" & Me.DatabaseName '***First attempt, no dice 'cSQLConn.ConnectionString = "Provider=sqloledb;" & _ ' "Data Source=NET-BRAIN;" & _ ' "Initial Catalog=DB_APP;" & _ ' "User Id=admin;" & _ ' "Password=mudslinger" 'cSQLConn.Open '***3rd attempt, no dice cSQLConn.Open "Provider=sqloledb;" & _ "Data Source=NET-BRAIN;" & _ "Initial Catalog=db_app;" & _ "User Id=admin;" & _ "Password=mudslinger", "admin", "mudslinger" thanks in advance.

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• How to connect from ruby to MS Sql Server

  - by apetrov

  Hi Crowd! I'm trying to connect to the sql server 2005 database from *NIX machine: I have the following configuration: Linux 64bit ruby -v ruby 1.8.6 (2007-09-24 patchlevel 111) [x86_64-linux] important gems: dbd-odbc (0.2.4) dbi (0.4.1) active record sql server adapter - as plugin ruby-odbc 0.9996 (installed without any options.) unixODBC is installed freeTDS is installed cat /etc/odbcinst.ini [FreeTDS] Description = TDS driver (Sybase/MS SQL) Driver = /usr/lib/libtdsodbc.so Setup = /usr/lib/odbc/libtdsS.so CPTimeout = CPReuse = FileUsage = 1 DSN: DRIVER=FreeTDS;TDS_Version=8.0;SERVER=XXXX;DATABASE=XXX;Port=1433;uid=XXX;pwd=XXXX;" or DRIVER=/usr/lib/libtdsodbc.so;TDS_Version=8.0;SERVER=XXXX;DATABASE=XXX;Port=1433;uid=XXX;pwd=XXXX;" I receive the following error: >>ActiveRecord::Base.sqlserver_connection({"mode"=>"ODBC", "adapter"=>"sqlserver", "dsn"=>my_dns) DBI::DatabaseError: IM002 (0) [unixODBC][Driver Manager]Data source name not found, and no default driver specified from /usr/lib/ruby/1.8/DBD/ODBC/ODBC.rb:95:in `connect' from /usr/lib/ruby/1.8/dbi.rb:424:in `connect' from /usr/lib/ruby/1.8/dbi.rb:215:in `connect' from /opt/ublip/rails/current/vendor/plugins/activerecord-sqlserver-adapter/lib/active_record/connection_adapters/sqlserver_adapter.rb:47:in `sqlserver_connection' It looks like ODBC unable to find appropriate ODBC driver, but I have no ideas why. I had a problem with /usr/lib/libtdsodbc.so which is empty in default debian package free-tds dev, but i solved it with remove broken package and installation from sources. Will appreciate any thought! Thanks & Regards Note: I'm albe to connect using the same steps on mac 10.5

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• Debugging SQL Server Slowness: Same Database, Different Servers

  - by Craig Walker

  For a while now we've been having anecdotal slowness on our newly-minted (VMWare-based) SQL Server 2005 database servers. Recently the problem has come to a head and I've started looking for the root cause of the issue. Here's the weird part: on the stored procedure that I'm using as a performance test case, I get a 30x difference in the execution speed depending on which DB server I run it on. This is using the same database (mdf) and log (ldf) files, detached, copied, and reattached from the slow server to the fast one. This doesn't appear to be a (virtualized) hardware issue: he slow server has 4x the CPU capacity and 2x the memory as the fast one. As best as I can tell, the problem lies in the environment/configuration of the servers (either operating system or SQL Server installation). However, I've checked a bunch of variables (SQL Server config options, running services, disk fragmentation) and found nothing that has made a difference in testing. What things should I be looking at? What tools can I use to investigate why this is happening?

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• SqlBulkCopy causes Deadlock on SQL Server 2000.

  - by megatoast

  I have a customized data import executable in .NET 3.5 which the SqlBulkCopy to basically do faster inserts on large amounts of data. The app basically takes an input file, massages the data and bulk uploads it into a SQL Server 2000. It was written by a consultant who was building it with a SQL 2008 database environment. Would that env difference be causing this? SQL 2000 does have the bcp utility which is what BulkCopy is based on. So, When we ran this, it triggered a Deadlock error. Error details: Transaction (Process ID 58) was deadlocked on lock resources with another process and has been chosen as the deadlock victim. Rerun the transaction. I've tried numerous ways to try to resolve it. like temporarily setting the connection string variable MultipleActiveResultSets=true, which wasn't ideal, but it still gives a Deadlock error. I also made sure it wasn't a connection time out problem. here's the function. Any advice? /// <summary> /// Bulks the insert. /// </summary> public void BulkInsert(string destinationTableName, DataTable dataTable) { SqlBulkCopy bulkCopy; if (this.Transaction != null) { bulkCopy = new SqlBulkCopy ( this.Connection, SqlBulkCopyOptions.TableLock, this.Transaction ); } else { bulkCopy = new SqlBulkCopy ( this.Connection.ConnectionString, SqlBulkCopyOptions.TableLock | SqlBulkCopyOptions.UseInternalTransaction ); } bulkCopy.ColumnMappings.Add("FeeScheduleID", "FeeScheduleID"); bulkCopy.ColumnMappings.Add("ProcedureID", "ProcedureID"); bulkCopy.ColumnMappings.Add("AltCode", "AltCode"); bulkCopy.ColumnMappings.Add("AltDescription", "AltDescription"); bulkCopy.ColumnMappings.Add("Fee", "Fee"); bulkCopy.ColumnMappings.Add("Discount", "Discount"); bulkCopy.ColumnMappings.Add("Comment", "Comment"); bulkCopy.ColumnMappings.Add("Description", "Description"); bulkCopy.BatchSize = dataTable.Rows.Count; bulkCopy.DestinationTableName = destinationTableName; bulkCopy.WriteToServer(dataTable); bulkCopy = null; }

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• Dynamic SQL To Dynamic LINQ in VB.NET with MS SQL Server 2008

  - by user337501

  I dread asking this question, because with what I've read so far I understand im gonna have to cram a lotta new things into my head. In spite of all the similiar questions(and the wide variety of answers) I thought I'd ask as nothing I've read tailors to what I need specifically enough. I need to represent the following query using LINQ: DECLARE @PurchasedInventoryItemID Int = 2 DECLARE @PurchasedInventorySectionID Int = 0 DECLARE @PurchasedInventoryItem_PurchasingCategoryID Int = 3 DECLARE @PurchasedInventorySection_PurchasingCategoryID Int = 0 DECLARE @IsActive Bit = 1 DECLARE @PropertyID Int = 2 DECLARE @PropertyValue nvarchar(1000) = 'Granny Smith' --Property1, Property2, Property3 ... SELECT O.PurchasedInventoryObjectID, O.PurchasedInventoryObjectName, O.PurchasedInventoryConjunctionID, O.Summary, O.Count, O.PropertyCount, O.IsActive FROM tblPurchasedInventoryObject As O INNER JOIN tblPurchasedInventoryConjunction As C ON C.PurchasedInventoryConjunctionID = O.PurchasedInventoryConjunctionID INNER JOIN tblPurchasedInventoryItem As I ON I.PurchasedInventoryItemID = C.PurchasedInventoryItemID INNER JOIN tblPurchasedInventorySection As S ON S.PurchasedInventorySectionID = C.PurchasedInventorySectionID INNER JOIN tblPurchasedInventoryPropertyMap as M ON M.PurchasedInventoryObjectID = O.PurchasedInventoryObjectID INNER JOIN tblPropertyValue As V ON V.PropertyValueID = M.PropertyValueID WHERE I.PurchasedInventoryItemID = @PurchasedInventoryItemID AND S.PurchasedInventorySectionID = @PurchasedInventorySectionID AND I.PurchasingCategoryID = @PurchasedInventoryItem_PurchasingCategoryID AND S.PurchasingCategoryID = @PurchasedInventorySection_PurchasingCategoryID AND O.IsActive = @IsActive AND V.PropertyID = @PropertyID AND V.Value = @PropertyValue Now, I know that a query in .NET doesnt look like this, this is my test in the SQL Design Studio. Naturally VB.NET variables will be used in place of the SQL local variables. My problem is this: All of the conditions after "WHERE" are optional. In that a query might be made that uses one, some, all, or none of the conditions. V.PropertyID and V.Value can also appear any number of times. In VB.NET I can make this query easy enough by simply concatenating strings, and using a loop to append the "V.PropertyID/V.Value" conditions. I can also make a Stored Procedure in MS SQL, which is easy enough. However, I want to accomplish this using LINQ. If anyone could direct me, I would be most appreciative.

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• Sql Server Compact - Schema Management

  - by Richard B

  I've been searching for some time for a good solution to implement the idea of managing schema on a Sql Server Compact 3.5 db. I know of several ways of managing schema on Sql Express/std/enterprise, but Compact Edition doesn't support the necessary tools required to use the same methodology. Any suggestions/tips? I should expand this to say that it is for 100+ clients with wrapperware software. As the system changes, I need to publish update scripts alongside the new binaries to the client. I was looking for a decent method by which to publish this without having to just hand the client a script file and say "Run this in SSMSE". Most clients are not capable of doing such a beast. A buddy of mine disclosed a partial script on how to handle the SQL Server piece of my task, but never worked on Compact Edition... It looks like I'll be on my own for this. What I think that I've decided to do, and it's going to need a "geek week" to accomplish, is that I'm going to write some sort of tool much like how WiX and nAnt works, so that I can just write an overzealous Xml document to handle the work. If I think that it is worthwhile, I'll publish it on CodePlex and/or CodeProject because I've used both sites a bit to gain better understanding of concepts for jobs I've done in the past, and I think it is probably worthwhile to give back a little.

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• Linq to SQL Problem System.Data.Linq.IdentityManager.StandardIdentityManager.MultiKeyManager

  - by luckyluke

  I have a really tricky thing going up here. My project has around 100 tables and they are all mapped by LINQ. Everything works fine in a dev and test environment. These enviroments are MS Win 2008 r2 servers with SQL 2008 sp1 databases. IIS and SQL are on a different machines. Now on production enviroment which is MS Win 2003 x64 web farm + geoclustered SQL 2008 IT DOES not work. All I get is the exception System.IndexOutOfRangeException: Index was outside the bounds of the array. at System.Data.Linq.IdentityManager.StandardIdentityManager.MultiKeyManager3.TryCreateKeyFr>om Values(Object[] values, MultiKey& k) at System.Data.Linq.IdentityManager.StandardIdentityManager.IdentityCache2.Find(Object[] keyValues) at System.Data.Linq.ChangeProcessor.GetOtherItem(MetaAssociation assoc, Object instance) at System.Data.Linq.ChangeProcessor.BuildEdgeMaps() at System.Data.Linq.ChangeProcessor.SubmitChanges(ConflictMode failureMode) at System.Data.Linq.DataContext.SubmitChanges(ConflictMode failureMode) at ERS.IIMP.Services.ExposuresSrv.Update(Int32 ExpID, Int32 AssID) Services\ExposuresSrv.cs` My question is What the hell. They have precisely the same DBML, the DB has exactly THE SAME structure (when I get the DB from prod to TEST and mount it eveything works just great), the binaries on the WEB Server are the same. I seriously do not know what to do.... Did anyone found that Linq works on one env and does not on the second?? I mam really lost here. I really hope You can help me:)

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• Embedded SQL in OO languages like Java

  - by Steve De Caux

  One of the things that annoys me working with SQL in OO languages is having to define SQL statements in strings. When I used to work on IBM mainframes, the languages used an SQL preprocessor to parse SQL statements out of the native code, so the statements could be written in cleartext SQL without the obfuscation of strings, for instance in Cobol there is a EXEC SQL .... END-EXEC syntax construct that allows pure SQL statements to be embedded in the Cobol code. <pure cobol code, including assignment of value to local variable HOSTVARIABLE> EXEC SQL SELECT COL_A, COL_B, COL_C INTO :COLA, :COLB, :COLC FROM TAB_A WHERE COL_D = :HOSTVARIABLE END_EXEC <more cobol code, variables COLA, COLB, COLC have been set> ...this makes the SQL statement really easy to read & check for errors. Between the EXEC SQL .... END-EXEC tokens there are no constraints on indentation, linebreaking etc., so you can format the SQL statement according to taste. Note that this example is for a single-row select, when a multiple-row resultset is expected, the coding is different (but still v. easy to read). So, taking Java as an example What made the "old COBOL" approach undesirable ? Not only SQL, but system calls could be made much more readable with that approach. Let's call it the embedded foreign language preprocessor approach. Would an embedded foreign language preprocessor for SQL be useful to implement ? Would you see a benefit in being able to write native SQL statements inside java code ? Edit I'm really asking if you think SQL in OO languages is a throwback, and if not then what could be done to make it better.

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• sql exception when transferring project from usb to c:\

  - by jello

  I'm working on a C# windows program with Visual Studio 2008. Usually, I work from school, directly on my usb drive. But when I copy the folder on my hard drive at home, an sql exception is unhandled whenever I try to write to the database. it is unhandled at the conn.Open(); line. here's the exception unhandled Database 'L:\system\project\the_project\the_project\bin\Debug\PatientMonitoringDatabase.mdf' already exists. Choose a different database name. Cannot attach the file 'C:\Documents and Settings\Administrator\My Documents\system\project\the_project\the_project\bin\Debug\PatientMonitoringDatabase.mdf' as database 'PatientMonitoringDatabase'. it's weird, because my connection string says |DataDirectory|, so it should work on any drive... here's my connection string: string connStr = "Data Source=.\\SQLEXPRESS;AttachDbFilename=|DataDirectory|\\PatientMonitoringDatabase.mdf; " + "Initial Catalog=PatientMonitoringDatabase; " + "Integrated Security=True"; Someone told me to: Connect to localhost with SQL Server Management Studio Express, and remove/detach the existing PatientMonitoringDatabase database. Whether it's a persistent database or only active within a running application, you can't have 2 databases with the same name at the same time attached to a SQL Server instance. So I did that, and now it gives me: Directory lookup for the file "C:\Documents and Settings\Administrator\My Documents\system\project\the_project\the_project\bin\Debug\PatientMonitoringDatabase.mdf" failed with the operating system error 5(Access is denied.). Cannot attach the file 'C:\Documents and Settings\Administrator\My Documents\system\project\the_project\the_project\bin\Debug\PatientMonitoringDatabase.mdf' as database 'PatientMonitoringDatabase' I checked the files' properties, and I have allow for everyone. Does anyone know what's going on here?

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• How do large blobs affect SQL delete performance, and how can I mitigate the impact?

  - by Max Pollack

  I'm currently experiencing a strange issue that my understanding of SQL Server doesn't quite mesh with. We use SQL as our file storage for our internal storage service, and our database has about half a million rows in it. Most of the files (86%) are 1mb or under, but even on fresh copies of our database where we simply populate the table with data for the purposes of a test, it appears that rows with large amounts of data stored in a BLOB frequently cause timeouts when our SQL Server is under load. My understanding of how SQL Server deletes rows is that it's a garbage collection process, i.e. the row is marked as a ghost and the row is later deleted by the ghost cleanup process after the changes are copied to the transaction log. This suggests to me that regardless of the size of the data in the blob, row deletion should be close to instantaneous. However when deleting these rows we are definitely experiencing large numbers of timeouts and astoundingly low performance. In our test data set, its files over 30mb that cause this issue. This is an edge case, we don't frequently encounter these, and even though we're looking into SQL filestream as a solution to some of our problems, we're trying to narrow down where these issues are originating from. We ARE performing our deletes inside of a transaction. We're also performing updates to metadata such as file size stats, but these exist in a separate table away from the file data itself. Hierarchy data is stored in the table that contains the file information. Really, in the end it's not so much what we're doing around the deletes that matters, we just can't find any references to low delete performance on rows that contain a large amount of data in a BLOB. We are trying to determine if this is even an avenue worth exploring, or if it has to be one of our processes around the delete that's causing the issue. Are there any situations in which this could occur? Is it common for a database server to come to the point of complete timeouts when many of these deletes are occurring simultaneously? Is there a way to combat this issue if it exists? (cross-posted from StackOverflow )

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• I get a "An attempt was made to load a program with an incorrect format" error on a SQL Server repli

  - by baldy

  The exact error is as follows "Could not load file or assembly 'Microsoft.SqlServer.Replication, Version=9.0.242.0, Culture=neutral, PublicKeyToken=89845dcd8080cc91' or one of its dependencies. An attempt was made to load a program with an incorrect format." I've recently started working on this project again after a two month move to another project. It worked perfectly before, and I've double checked all the references.

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• SQL query recursion for a web-like structure

  - by MickeyD

  I have a table here, named "Foo". The data is set up something like this. ID TableReference DataId0 DataId1 DataId2 -- -------------- ------- ------- ------- 1 Prize 3 4 5 2 Prize 4 5 NULL 3 Cash 1 NULL NULL 4 Prize 8 NULL 12 5 Foo 2 3 NULL 6 Cash 8 1 10 7 Foo 5 1 2 Etc. The data is horribly set up, I know, but I didn't set it up that way. :) I'm only dealing with the after effect. I'm trying to come up with a way to essentially "flatten" the table; that is, to display all the data to a point where the table "Foo" does not reference itself. I'm trying to figure out a sql query that I can do to get there. Usually when I deal with recursion, I have (or can establish) parent IDs and set it up that way, but for this table there are seemingly multiple child and parent IDs creating a web-like structure instead of a hierarchy. So I'm at a loss where to even begin to write a sql query for something like this. Note: There is no infinite looping (where one Foo points to another Foo, which points back to the original Foo) from what I've found. Using t-sql. Thanks for any assistance, if at all possible.

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• SQL - Updating records based on most recent date

  - by Remnant

  I am having difficulty updating records within a database based on the most recent date and am looking for some guidance. By the way, I am new to SQL. As background, I have a windows forms application with SQL Express and am using ADO.NET to interact with the database. The application is designed to enable the user to track employee attendance on various courses that must be attended on a periodic basis (e.g. every 6 months, every year etc.). For example, they can pull back data to see the last time employees attended a given course and also update attendance dates if an employee has recently completed a course. I have three data tables: EmployeeDetailsTable - simple list of employees names, email address etc., each with unique ID CourseDetailsTable - simple list of courses, each with unique ID (e.g. 1, 2, 3 etc.) AttendanceRecordsTable - has 3 columns { EmployeeID, CourseID, AttendanceDate, Comments } For any given course, an employee will have an attendance history i.e. if the course needs to be attended each year then they will have one record for as many years as they have been at the company. What I want to be able to do is to update the 'Comments' field for a given employee and given course based on the most recent attendance date. What is the 'correct' SQL syntax for this? I have tried many things (like below) but cannot get it to work: UPDATE AttendanceRecordsTable SET Comments = @Comments WHERE AttendanceRecordsTable.EmployeeID = (SELECT EmployeeDetailsTable.EmployeeID FROM EmployeeDetailsTable WHERE (EmployeeDetailsTable.LastName =@ParameterLastName AND EmployeeDetailsTable.FirstName =@ParameterFirstName) AND AttendanceRecordsTable.CourseID = (SELECT CourseDetailsTable.CourseID FROM CourseDetailsTable WHERE CourseDetailsTable.CourseName =@CourseName)) GROUP BY MAX(AttendanceRecordsTable.LastDate) After much googling, I discovered that MAX is an aggregate function and so I need to use GROUP BY. I have also tried using the HAVING keyword but without success. Can anybody point me in the right direction? What is the 'conventional' syntax to update a database record based on the most recent date?

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