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SQL Anywhere 12.0.0 (Français) » SQL Anywhere Server - SQL Usage » Monitoring and improving database performance » Improving database performance » Performance improvement tips


Declare constraints

Undeclared primary key-foreign key relationships exist between tables when there is an implied relationship between the values of columns in different tables. It is true that not declaring the relationship can save time on index maintenance, however, declaring the relationship can improve performance of queries when joins take place because the cost model is able to do a better job of estimation. See Using table and column constraints.