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 ...

Check constraints are supported in all of the major DBMS products, including DB2, Oracle, and SQL Server. But they are too-often ignored and not implemented in production databases. Properly defined, ...

A constraint checks the values you insert or update in a table against the conditions specified by the constraint. For example, a constraint could ensure that the value entered for the column GENDER ...

Want to improve the integrity of your data? Place constraints in the database, as well as in your application. NoSQL, the catchall phrase for non-relational databases, is all the rage among Web ...

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 ...