How to set the default schema of a database in SQL Server 2005?

A default schema is user-specific:

USE yourDatabase;
ALTER USER [yourUser] WITH DEFAULT_SCHEMA = myschema;

More information about the ALTER TABLE for SQL 2005 might help you as well.

As this is user-specific, if you have multiple users, you will need to execute this query (on each database) for each user whose default schema you want to update.

It is important to note:

The value of DEFAULT_SCHEMA is ignored if the user is a member of the sysadmin
fixed server role. All members of the sysadmin fixed server role have a default
schema of dbo.

Like user960567, I tried the answers from both Adam and Ivan and could not get it working.

I was running:

ALTER USER myuser WITH DEFAULT_SCHEMA=newschema

as suggested, but after executing this and executing

SELECT SCHEMA_NAME()

it was still returning 'dbo' as the default schema.

To fix this I executed:

ALTER USER myuser WITH DEFAULT_SCHEMA=newschema EXECUTE AS USER='myuser'

and it worked as expected - now executing:

SELECT SCHEMA_NAME()

returns 'newschema'.

You can use:

ALTER USER Mary51 WITH DEFAULT_SCHEMA = Purchasing;

To set the default schema for user.