Object ownership in SQL Server can be a confusing concept for new DBAs and developers. It is often assumed that tables, views, and stored procedures created by a member of the db_owner database role would be owned by dbo by default, but that is not always the case. This article aims to clarify the concept of object ownership and provide a script that can be used to change the owner of multiple tables at once.
Object Ownership in SQL Server
Before diving into the details, let’s summarize what to expect when it comes to object ownership in SQL Server:
- An object created by an account with sa rights or the owner of the database defaults to dbo ownership.
- If an object is created by a member of the db_owner role without explicitly specifying dbo as the owner, the object will be owned by the creator.
- When a user queries an object without specifying the owner, SQL Server first looks for an object owned by the user. If one is not found, it then looks for an object owned by dbo.
- If multiple users own objects with the same name, it can lead to confusion and potential issues.
Understanding object ownership is important because it affects how queries are executed and how objects are accessed. For example, if a user queries a table without specifying the owner, they may retrieve rows from a different table with the same name but owned by a different user.
Real-Life Examples
Let’s explore a couple of real-life examples to illustrate the importance of object ownership:
Example 1: Packaged Software Applications
In some cases, packaged software applications may drop and recreate tables during installation or maintenance. If the account used for these tasks is a member of the db_owner role, all new objects will be owned by that account. This can cause issues if the software expects the tables to be owned by a different account, leading to broken functionality. To resolve this, the account can be made the owner of the database, ensuring that the tables can be accessed correctly.
Example 2: Multiple Legal Case Databases
In a law firm, a software package may create a separate database for each legal case. Occasionally, the wrong account may be used during setup, resulting in all objects being owned by the incorrect account. To quickly fix this issue, a script can be used to rename the objects and transfer ownership to the correct account.
Changing Object Owners
If you need to change the owner of multiple tables in SQL Server, you can use the following script:
use YourDatabaseName
go
declare @OldOwner varchar(100)
declare @NewOwner varchar(100)
set @OldOwner = 'OldOwner'
set @NewOwner = 'NewOwner'
select 'sp_changeobjectowner ''[' + table_schema + '].[' + table_name + ']'', ''' + @NewOwner + '''
go'
from information_schema.tables where Table_schema = @OldOwner
Replace “YourDatabaseName” with the name of your database, and set the values of @OldOwner and @NewOwner to fit your situation. Running this script will generate a second script that can be executed to change the owner of all tables owned by the specified account.
Conclusion
Understanding object ownership in SQL Server is crucial for managing and accessing database objects effectively. By explicitly stating the owner when creating scripts and being aware of potential ownership issues, you can avoid confusion and ensure smooth operation of your SQL Server environment.