[url removed, login to view] DATA BASE A relational database is a database that has a collection of tables of data items, all of which is formally described and organized according to the relational model. The term is in contrast to only one table as the database, and in contrast to other models which also have many tables in one database.
In the relational model, each table schema must identify a primary column, called the primary key, used for identifying a row. Tables can relate by using a foreign key that points to the primary key of another table. The relational model offers various levels of refinement of the table relations called database normalization. (See Normalization below.) The database management system(DBMS) of a relational database is called an RDBMS, and is the software of a relational database.
The relational database was first defined in June 1970 by Edgar Codd, of IBM's San Jose Research Laboratory. Codd's view of what qualifies as an RDBMS is summarized in Codd's 12 rules. A relational database has become the predominant choice in storing data. Other models besides the relational model include