size of varchars

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ryan putman - 03 Mar 2008 20:16 GMT

Someone else asked this and got referred to a Discussion that didn't
address the question so I'm going to ask again.

If you have a column that typically is going to be less than 12
characters in length, the obvious choice would be to use a
varchar(12). However, what is the drawback to using something
larger.....like varchar(30)?

Thanks in Advance.
Ryan Putman

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Andrew J. Kelly - 04 Mar 2008 01:28 GMT

None really, the overhead for a variable length column is there regardless.
But if the data should never be more than 12 chars in length by making the
column larger you risk someone putting bad data in.

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Andrew J. Kelly SQL MVP
Solid Quality Mentors

> Someone else asked this and got referred to a Discussion that didn't
> address the question so I'm going to ask again.
[quoted text clipped - 6 lines]
> Thanks in Advance.
> Ryan Putman

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TheSQLGuru - 04 Mar 2008 14:46 GMT

Actually the choice to use var or not depends on what is being put into the
column, expecially the average length of the values. If every value is
either 11 or 12 chars in length you should use a char(12) not a varchar.
This is more efficient both from a processing and storage standpoint.

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Kevin G. Boles
Indicium Resources, Inc.
SQL Server MVP
kgboles a earthlink dt net

> Someone else asked this and got referred to a Discussion that didn't
> address the question so I'm going to ask again.
[quoted text clipped - 6 lines]
> Thanks in Advance.
> Ryan Putman

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