by Polun L
In the article, “Referential Integrity Tips”, by Burleson, talks about the functionality of referential integrity in Oracle. Referential integrity can be used to make sure that valid data can be enforced with constraints, and relationships in schema are enforced properly. In addition, Burleson mentions that there are several types of constraints which can be used to integrate the data. Oracle check constraint insures that updated and inserted values meet a specific condition. The check constraint condition must return a true and false. For example, when the condition is true, the value will be accepted; otherwise, it will be rejected when it is false. Not null constraint is used to enforce sql insert and update time. Also, columns never contain a null value. Primary key constraint is pretty straight forward because it is used to identify the primary key for a table. References constraint, which is also called foreign key constraint, indentifies a column of table or view in a database and establishes a direct relationship with a primary key. All in all, those constraints are several ways for maintaining business rules.
What I have learned from this article is that database system must have a set of enforcing basic business rules so that database is able to proceed actions such as insert, delete, or update without interruption. Primary key, foreign key, and not null constraints are basically learned from the class. As for referential integrity, which will be taught in the class this week, is a foreign key constraint. Actually, I am still not sure if RI and FK function the same, or they have its own unique way to control tables. I am expecting to learn more information in the class later.
(2011). Referential integrity tips. Retrieved from http://www.dba-oracle.com/art_builder_ri.htm