Dynamically Generating T-SQL Statements in SQL Server

This article discusses about dynamically generating T-SQL statements for SQL Server database administration and development purposes.

Why Dynamically Generating T-SQL Statements?

So you have many databases, objects, etc. and you want to massively administer it right?

In some of my previous posts I explained the undocumented stored procedures “sp_msforeachdb” and “sp_msforeachtable” that allow you to massively perform changes on all databases and tables within a SQL Server instance.

But isn’t it handier to generate dynamic T-SQL for doing that? I believe it is!

By using some of the catalog views in SQL Server 2005 or later you can easily do that.

The idea is to use a basic SELECT statement and then dynamically build the T-SQL expression that eventually will generate the desired T-SQL code.

Here are some examples (before running the code, right-click in the query window, then select “Results To” and finally “Results to Text”):

Example 1: See the physical files used for each database

SELECT
'USE '+ name +';'+' SELECT name,physical_name FROM SYS.DATABASE_FILES' FROM SYS.databases

Example 2: Change the schema owner for all tables within a database

SELECT
'ALTER SCHEMA [NEW_SCHEMA_NAME] TRANSFER ' + s.Name + '.' + t.Name FROM sys.Tables t INNER JOIN
sys.Schemas s on t.schema_id = s.schema_id WHERE s.Name = ['OLD_SCHEMA_NAME']

Example 3: Change the schema owner for all stored procedures within a database

SELECT
'ALTER SCHEMA [NEW_SCHEMA_NAME] TRANSFER ' + s.Name + '.' + sp.Name FROM sys.Procedures sp INNER JOIN
sys.Schemas s on sp.schema_id = s.schema_id WHERE s.Name = ['OLD_SCHEMA_NAME']

SELECT
'USE '+ s.name +';'+' SELECT * FROM sys.views' FROM SYS.databases s

Example 5: Change the compatibility level for all the databases to 100 (SQL Server 2008)

SELECT
'ALTER DATABASE '+ name + ' SET COMPATIBILITY_LEVEL = 100' FROM SYS.DATABASES

Example 6: Set all the databases to READ ONLY mode

SELECT
'ALTER DATABASE '+ name + ' SET READ_ONLY WITH ROLLBACK IMMEDIATE' FROM SYS.DATABASES

Example 7: Set all the databases to READ/WRITE mode

SELECT
'ALTER DATABASE '+ name + ' SET READ_WRITE WITH ROLLBACK IMMEDIATE' FROM SYS.DATABASES

… and the list goes on!

When using this technique along with the information retrieved from the catalog views, the possibilities are endless!

Yes, you still need to manually execute each generated T-SQL statement but the good thing is that the statements are being generated dynamically and by manually executing them, you have more control over your SQL Server instance.

I hope this helps!

Until next time!