Question

I use the database name in several places in my script, and I want to be able to quickly change it, so I’m looking for something like this:

DECLARE @DBNAME VARCHAR(50) SET @DBNAME = 'TEST'  CREATE DATABASE @DBNAME GO ALTER DATABASE @DBNAME SET COMPATIBILITY_LEVEL = 90 GO ALTER DATABASE @DBNAME SET RECOVERY SIMPLE  GO 

But it doesn’t work. So what’s the correct way to write this code?

Answer 1

Put the entire script into a template string, with {SERVERNAME} placeholders. Then edit the string using:

SET @SQL_SCRIPT = REPLACE(@TEMPLATE, '{SERVERNAME}', @DBNAME) 

and then run it with

EXECUTE (@SQL_SCRIPT) 

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It’s hard to believe that, in the course of three years, nobody noticed that my code doesn’t work!

You can’t EXEC multiple batches. GO is a batch separator, not a T-SQL statement. It’s necessary to build three separate strings, and then to EXEC each one after substitution.

I suppose one could do something ‘clever’ by breaking the single template string into multiple rows by splitting on GO; I’ve done that in ADO.NET code.

And where did I get the word ‘SERVERNAME’ from?

Here’s some code that I just tested (and which works):

DECLARE @DBNAME VARCHAR(255) SET @DBNAME = 'TestDB'  DECLARE @CREATE_TEMPLATE VARCHAR(MAX) DECLARE @COMPAT_TEMPLATE VARCHAR(MAX) DECLARE @RECOVERY_TEMPLATE VARCHAR(MAX)  SET @CREATE_TEMPLATE = 'CREATE DATABASE {DBNAME}' SET @COMPAT_TEMPLATE='ALTER DATABASE {DBNAME} SET COMPATIBILITY_LEVEL = 90' SET @RECOVERY_TEMPLATE='ALTER DATABASE {DBNAME} SET RECOVERY SIMPLE'  DECLARE @SQL_SCRIPT VARCHAR(MAX)  SET @SQL_SCRIPT = REPLACE(@CREATE_TEMPLATE, '{DBNAME}', @DBNAME) EXECUTE (@SQL_SCRIPT)  SET @SQL_SCRIPT = REPLACE(@COMPAT_TEMPLATE, '{DBNAME}', @DBNAME) EXECUTE (@SQL_SCRIPT)  SET @SQL_SCRIPT = REPLACE(@RECOVERY_TEMPLATE, '{DBNAME}', @DBNAME) EXECUTE (@SQL_SCRIPT)