Creating windows azure Sql table

Question

While creating Windows Azura SQL database, this script will be available to you.

The script shown below is supposed to prevent possible collisions that occurs when two tables have exactly the same name.

My question is: Can anyone explain in details how this code works Note: I have a good background of Databases and using of SQL

IF NOT EXISTS (SELECT * FROM sys.objects WHERE object_id = OBJECT_ID(N'[dbo].[Department]') AND type in (N'U'))

cillierscharl · Accepted Answer · 2013-01-26 09:39:41Z

1

sys.objects - MSDN:

Contains a row for each user-defined, schema-scoped object that is created within a database.

sys.objects.type:

U = Table (user-defined)

OBJECT_ID - MSDN:

Returns the database object identification number of a schema-scoped object.

Hence, you query for the existence of the object id returned by passing an object name to the OBJECT_ID function specifying that the type should be a table.

If it does not exist, it wouldn't return any rows and thus not satisfy the condition in your wrapping statement : IF NOT EXISTS

answered Jan 26, 2013 at 9:39

cillierscharl

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3 Comments

marc_s Over a year ago

And most likely, SQL Azure would also support sys.tables which is focused on tables (then you don't need to specify the type of the object anymore - that's a given by nature of the catalog view you're looking at)

A.Shoman Over a year ago

Ok thanks but what does the letter N in "type in (N'U')" mean ?

cillierscharl Over a year ago

As listed above. type = u means user defined table. The N is just there for nvarchar if I remember correctly.

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