When I am working with an Oracle database, I still find myself using SQL*Plus for many quick and dirty database queries. In particular, I often look up constraints in SQL*Plus. In this post, I ...

Furthermore, the unique constraint columns may be set to null. Data type and data length are the most fundamental integrity constraints applied to data in the database. Simply by specifying the data ...

From the perspective of the primary key, it is good database design to forbid modifying primary keys. If a primary key value is updated, three options exist for handling foreign key values: (1) ...

By using cascading referential integrity constraints, you can define the actions that SQL Server 2005 takes when a user tries to delete or update a key to which existing foreign keys point. Skip ...