How to use a variable for the database name in T-SQL?
sql-server
Solution
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)
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)
Problem
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?