Monday, May 4, 2015

Transferring Ownership of All Database Objects Back to DBO

Consider the following scenario: You created a Window or SQL login in SQL Server and in the user mapping along with assigning a database role membership, you assigned as default schema something different than the “dbo”.

Take as an example the following screenshot:










































As you can see, the SQL login “testLogin” has been assigned the database role “db_owner” on the database “SampleDB1” but along with that, “testLogin” was also set as the default schema.

If you do that, any object the login “testLogin” creates, their owner schema will be “testLogin” and not “dbo”.

If however, for any reason you want to remove “testLogin” from the SQL Server instance you will not be able to do it because the login, through its schema, will own database objects.

If you still want to remove the login don’t lose hope, there is a way! :)

For achieving the above you need to transfer back the ownership of the objects to the “dbo” (or any other) schema.

You can do that using the “ALTER SCHEMA” command. As described in BOL, this command transfers a securable between schemas.

So how can you use this command in order to transfer back to dbo all objects owned by "testLogin"?

One of the easiest approaches is to generate the set of SQL statements that you can run in order to restore ownership for all objects of the following types:
- tables
- views
- functions (scalar, table-valued)
- stored procedures
- ...and maybe any other object types


A sample logic that could do that would be:

--User Option 1: Set the database (in this example "SampleDB1")
USE SampleDB1
GO

--Variable declarations
DECLARE @currentSchema VARCHAR(100)
DECLARE @newSchema VARCHAR(100)

--User Options 2 and 3: set the current schema and the new schema 
--to which you want to transfer the selected database's objects
--in this example current schema='testLogin' and new schema='dbo'
SET @currentSchema='testLogin'
SET @newSchema='dbo'

DECLARE @schemaID INT
SET @schemaID=(SELECT [schema_id] FROM sys.schemas WHERE [name]=@currentSchema)

--The actual logic
IF OBJECT_ID('TempDB..#Statements') IS NOT NULL
DROP TABLE #Statements

CREATE TABLE #Statements(
ScriptToRun VARCHAR(200)
)

--Generate statements for all user tables
INSERT INTO #Statements      
SELECT 'ALTER SCHEMA ' + @newSchema + ' TRANSFER ' + @currentSchema + '.' + [name]
FROM sys.objects
WHERE type='U' AND [schema_id]=@schemaID

--Generate statements for all user views
INSERT INTO #Statements      
SELECT 'ALTER SCHEMA ' + @newSchema + ' TRANSFER ' + @currentSchema + '.' + [name]
FROM sys.objects
WHERE type='V' AND [schema_id]=@schemaID

--Generate statements for all stored procedures
INSERT INTO #Statements      
SELECT 'ALTER SCHEMA ' + @newSchema + ' TRANSFER ' + @currentSchema + '.' + [name]
FROM sys.objects
WHERE type='P' AND [schema_id]=@schemaID

--Generate statements for all scalar functions
INSERT INTO #Statements      
SELECT 'ALTER SCHEMA ' + @newSchema + ' TRANSFER ' + @currentSchema + '.' + [name]
FROM sys.objects
WHERE type='FN' AND [schema_id]=@schemaID

--Generate statements for all table-valued-functions
INSERT INTO #Statements      
SELECT 'ALTER SCHEMA ' + @newSchema + ' TRANSFER ' + @currentSchema + '.' + [name]
FROM sys.objects
WHERE type='TF' AND [schema_id]=@schemaID

--Set "Results to Text" (Ctrl + T)
SELECT * FROM #Statements

Then, if you want to proceed with the transfer of ownership you can use the generated "ScriptToRun", that is the contents of the temporary table #Statements.

Note 1: As all posts in this blog, this post is provided as-is and for educational purposes only. Do not play with your Production environments if you do not know what you are doing and of course, always take backups of your data.

Note 2: In the above logic we searched for user tables and views, stored procedures and scalar/table-valued functions. You can search for even more database object types in a similar way (more info in one of my previous posts).

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Artemakis Artemiou [MVP]

Author & Editor

Artemakis Artemiou is a Senior SQL Server Architect, Software Developer and Microsoft Data Platform MVP. He is also an author, regular blogger, president of Cyprus.NET User Group and CY Country leader of INETA-EU. He is also the creator of DBA Security Advisor and In-Memory OLTP Simulator. Artemakis is a frequent guest author of worldwide well-respected online journals where he writes articles focusing on many SQL Server topics.

Reference: The SQL Server and .NET Hub (http://www.sqlnethub.com)

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