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Foreign key on two fields
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Forum:
Microsoft SQL Server
Category:
Other
Title:
Foreign key on two fields
Environment versions
SQL Server:
SQL Server 2005
Miscellaneous
Thread ID:
01520713
Message ID:
01520713
Views:
106
Hi,

Say I want to create a Foreign key constraint on two fields (one char and one smallint). In the parent table (where the combination of these two fields is unique) I will have a unique index on Char_field + SmallInt_fld.

Do I need to have an index in the Child table (where the Foreign key constraint will be set) on these two fields (Char_field + SmallInt_fld) or two index keys, one for each field?

The foreign key constrain will look something like this:


ALTER TABLE [dbo].[child_table] WITH CHECK ADD CONSTRAINT [FK_child_somename]
FOREIGN KEY([char_fld], [smallint_fld])
REFERENCES [dbo].[parent_table] ([char_fld], [smallint_fld])
ON UPDATE CASCADE


TIA.
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