Does specifying a foreign key make it an index?

Question

I have a table T with a primary key id and foreign key f. Is f automatically indexed when it is specified as a foreign key? Do I need explicitly add an index for f ?

Answer 1

In case of the foreign key constraint, the foreign key f in table T would be a primary key in the referenced table say T2. In SQL Server a clustered index would be automatically created when T2 got created.

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