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Christopher Fox
Starting Member
1 Post |
 Posted - 2015-02-01 : 13:55:41
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I need to prevent a user from entering a serial number that already exists in any of four other tables. Can a constraint check other tables? Can a constraint contain some SELECT statements? Thanks for any help! |
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robvolk
Most Valuable Yak
15732 Posts |
Posted - 2015-02-01 : 16:42:54
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| The only inter-table constraint supported by SQL Server is a foreign key. You would have to code a multi-table duplicate check in a stored procedure or trigger.Any reason why the serial numbers are in 4 different tables and not one table? |
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gbritton
Master Smack Fu Yak Hacker
2780 Posts |
Posted - 2015-02-01 : 22:26:03
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| You can do what you want. Write a UDF that takes the number to check, checks the other 4 tables and returns a bit. Call the UDF in the constraint and check the |
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gbritton
Master Smack Fu Yak Hacker
2780 Posts |
Posted - 2015-02-01 : 22:26:35
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Constraints across tables