what is the first schema checked?

Question

I am a little confused right now. Can someone answer me with a simple answer to this question.

I have a user [user_test] and has [db_owner] role assigned to him for one database [database_test]. The user's default schema is [user_test] and almost all objects from the [database_test] are created under schema [user_test]. In the database exist 3 more objects with schema [dbo]

The user has rights to both schemas: [dbo] and [user_test] without explicitly specifying them in select statements in front of objects reference.

What is the first schema checked by SQL when an object is called by user [user_test] ?

I mean, If [user_test] issues a select for an object from dbo schema (without schema in front), will SQL first check in it's default schema specified and then in dbo?

thanks,

Answer 1

With SQL Server 2005 & 2008 the first schema that is searched is the users default schema.

from SQL Server Best Practices – Implementation of Database Object Schemas

Default Schema

Users can be defined with a default schema. The default schema is the first schema that is searched when it resolves the names of objects it references.

and

creating the base tables in the dbo schema will enable table objects to be referred to without an explicit schema name. This is because an object will be located by searching the default schema first, followed by the dbo schema. So:

SELECT * FROM Table1

Will assess the following statement first:

SELECT * FROM <defaultschema>.Table1

If it cannot find the object, the server will assess the following statement:

SELECT * FROM dbo.Table1

The assessment process can be improved by using either the fully qualified name or the DEFAULT_SCHEMA option described earlier. By setting a value for DEFAULT_SCHEMA for the user, the server will check the DEFAULT_SCHEMA first, removing an unnecessary ownership checking process.

This can improve performance considerably on heavily utilized systems.

Default Schema was introduced in SQL Server 2005 Upgrading to SQL Server 2005 and DEFAULT_SCHEMA setting