INFORMATION_SCHEMA.COLUMN_DOMAIN_USAGE



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Overview
The INFORMATION_SCHEMA.COLUMN_DOMAIN_USAGE view allows you to get information about alias data types that are used for columns By default it will show you this information for every single table and view that is in the database that uses an alias data type.

Explanation
This view can be called from any of the databases in an instance of SQL Server and will return the results for the data within that particular database.

The columns that this view returns are as follows:

Column name Data type Description
DOMAIN_CATALOG nvarchar(128) Database in which the alias data type exists.
DOMAIN_SCHEMA nvarchar(128) Name of schema that contains the alias data type.
DOMAIN_NAME sysname Alias data type.
TABLE_CATALOG nvarchar(128) Table qualifier.
TABLE_SCHEMA nvarchar(128) Table owner.
TABLE_NAME sysname Table in which the alias data type is used.
COLUMN_NAME sysname Column using the alias data type.

(Source: SQL Server 2005 Books Online)


Here is an example of data that was pulled from the AdventureWorks database.  This data was pulled using this query:

SELECT * FROM INFORMATION_SCHEMA.COLUMN_DOMAIN_USAGE

In the results below we can see that the data type "Name" in the DOMAIN_NAME column is used in several tables for columns ReviewerName (ProductReview) and Name (AddressType, ProductSubcategory, UnitMeasure).


To see the underlying data types for these aliased data types you can use this query.

SELECT DISTINCT DOMAIN_NAME, DATA_TYPE, CHARACTER_MAXIMUM_LENGTH
FROM
INFORMATION_SCHEMA.COLUMNS
WHERE
DOMAIN_NAME IS NOT
NULL

Last Update: 7/2/2009






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