Question

Would the following SQL statement automatically create an index on Table1.Table1Column, or must one be explicitly created?

Database engine is SQL Server 2000

       CREATE TABLE [Table1] ( . . .             CONSTRAINT [FK_Table1_Table2] FOREIGN KEY              (                 [Table1Column]             ) REFERENCES [Table2] (                 [Table2ID]             )          ) 

Answer 1

SQL Server will not automatically create an index on a foreign key. Also from MSDN:

A FOREIGN KEY constraint does not have to be linked only to a PRIMARY KEY constraint in another table; it can also be defined to reference the columns of a UNIQUE constraint in another table. A FOREIGN KEY constraint can contain null values; however, if any column of a composite FOREIGN KEY constraint contains null values, verification of all values that make up the FOREIGN KEY constraint is skipped. To make sure that all values of a composite FOREIGN KEY constraint are verified, specify NOT NULL on all the participating columns.