Month: May 2015

SQL Server: Migrating a Database from version 2008 to 2012 Part I

JamesNT SQL Administration, SQL Server ,

A lot of companies out there are still on SQL Server 2008 (some are still using 2005!).  Now that SQL Server 2012 has been out awhile, I’m seeing questions on what it takes to migrate a database from SQL Server 2008 to 2012.  The bad news is doing an in-place upgrade from 2008 to 2012 is out of the question.  For one thing, many of you are still running SQL Server 2008 on Windows Server 2003 and SQL Server 2012 requires Windows Server 2008 Service Pack 2 or higher.  So you’re going to stand up a new server no matter what.  The good news is that it’s still easy.  In fact, you have two ways to do it.  Either perform a backup and restore or do a detach and attach.  This part covers backup and restore.

Backup and Restore

You can back up your SQL Server 2008 database and restore it to a SQL Server 2012 machine.  Keep in mind that I’m talking about user databases, not any of the system databases.

First, back up your SQL 2008 database.

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Once your backup is complete, copy the BAK file over to your new server.  Once done, restore the database.  Note that you don’t have to create a database first just to restore over it.

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Once your database is restored, you can set compatibility level options in case you have older applications that expect some type of older behavior.

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Keep in mind that this option is not a panacea and that you should thoroughly test before just shutting off your old SQL Server 2008 machine to ensure current applications don’t depend on some old behavior or deprecated feature.  Also, do keep in mind that despite setting the compatibility level to SQL Server 2008, the database file format itself is still upgraded to SQL Server 2012.  This means you cannot move the database back to your old SQL Server 2008 machine.  If you need to move back, you’ll have to extract all the data that has changed since the last backup and import manually.  I know of no way to restore or attach a SQL Server 2012 database to an older version of SQL Server.

JamesNT

SSIS: Using Expressions to build SQL Statements for ADO.NET Connections

JamesNT SQL Server, SSIS , , ,

In SQL Server Integration Services, you can specify that an OLE DB Connection use a SQL Statement from a variable.

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Using this approach, you can dynamically build SQL statements using the OLE DB Connection.  But what about ADO.NET?

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It appears we have no way to dynamically build SQL statements when using ADO.Net providers.  And to think I’ve been standardizing on them.  On the other hand, maybe we do have a way.  I made a package with two variables.  One is a DateTime called LoadControl and the other is a string called strSQL.  I’m going to load a DateTime from a load control table into the LoadControl variable then use the LoadControl variable to build the WHERE clause of a SQL statement to pull out all medical claims with a date of service greater than or equal to the LoadControl date.  First, our variables.

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Nothing hard about that.  Next, our Execute SQL task to populate the LoadControl variable.

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Next up, our data flow. 

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The only thing I’ve done is set up the ADO.Net Source.  Now we need to get our strSQL variable populated.  First, be certain to set the property EvaluateAsExpression to TRUE for strSQL.

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Next, create an expression for this variable like so.  Notice that since DateTime variables cannot be NULL when you create them, SSIS fills in the current DateTime, hence the 5/3/2015 7:38:04 PM.

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Now the interesting part.  From the Control Flow, single-left click your data flow to highlight it.  Now, look over at your Properties for your data flow.  Scroll down to the Misc. section. 

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That’s right, you see the SQL statement for the ADO.Net source.  Of course, this is where it is important to call your connection sources something meaningful so you can find them readily (I didn’t bother since we only have one).    Notice that we have two spots for the ADO.Net source:  SQL Command and TableOrViewName.  We aren’t going to change the SQL statement there.  Rather, go down further until you see Expressions.  That’s right, build an expression.

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Notice that for this expression, we only need the strSQL variable.  Once you have that saved, put a data viewer on your package and run it.

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Notice that only dates for 4/10/2015 or higher are shown (I added an Order By to the SQL Statement in strSQL and 4/10/2015 is what was in our LoadControl Table).  This is where our Expression was evaluated and placed in for the SQL Command of the ADO.Net source.  One thing of note, notice how before I set up a SQL statement in the ADO.NET Connection when I first created it earlier.  This statement is IGNORED when the Expression is evaluated.  However, if the SQL Statement in your Expression adds or changes columns, you may need to go into the Advanced Editor of the ADO.NET Connection and click Refresh to get those changes to show.  Otherwise, your new or changed columns may not show up in the data flow right away.

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With this approach, you can still dynamically build SQL statements for ADO.NET Connections like you can OLE DB Connections.  A little more work, yes, but I think worth it when you have lots of Script Tasks/Components that need to use Connection Managers.

JamesNT