Introduction
This artcile explains the use of ROWGUIDCOL in SQL Server.
Background
Normally, when we use UNIQUEIDENTIFIER column for PRIMARY KEY, we assign NEWID() as the DEFAULT value for the column. SQL Server offers a more efficient and convenient way of achieving it.
Using the Code
For example, this is what we would normally use:
CREATE TABLE MyTable (ID UNIQUEIDENTIFIER PRIMARY KEY DEFAULT NEWID()...
Instead of the above, we can use the below definition:
CREATE TABLE MyTable (ID UNIQUEIDENTIFIER ROWGUIDCOL PRIMARY KEY DEFAULT NEWSEQUENTIALID()...
Points of Interest
We have the below advantages with this approach:
1) The UNIQUEIDENTIFIER along with
ROWGUIDCOL NEWSEQUENTIALID() is far more efficient than normal
UNIQUEIDENTIFIER along with
NEWID().
2) The Unique Ids generated with the second approach are sequential in nature, similar to
IDENTITY values.
3) There can be max of one
ROWGUIDCOL for a table.
4) You can query the table for
ROWGUIDCOL. Example:
SELECT ROWGUIDCOL FROM MyTable
History
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Ravikiran Malladi is a senior software professional in Microsoft technologies. He has global IT experience of over 10 years and has compulsive habit of writing tools, particularly for the projects he works on. He has vast experience in the roles of senior developer, technical analyst, technical architect besides in technical lead roles.
His hobbies include chess, music, cricket, web sites along side writing technical articles and technical blogs.
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