Who introduced the 12 rules of relational database ?
edgar f.codd introduced these 12 rules n these rules are: Rule 0: The system must qualify as relational, as a database, and as a management system. For a system to qualify as a relational database management system (RDBMS), that system must use its relational facilities (exclusively) to manage the database. Rule 1: The information rule: All information in the database is to be represented in one and only one way, namely by values in column positions within rows of tables. Rule 2: The guaranteed access rule: All data must be accessible. This rule is essentially a restatement of the fundamental requirement for primary keys. It says that every individual scalar value in the database must be logically addressable by specifying the name of the containing table, the name of the containing column and the primary key value of the containing row. Rule 3: Systematic treatment of null values: The DBMS must allow each field to remain null (or empty). Specifically, it must support a representation
Hi Harish, Codd’s 12 rules Codd’s 12 rules are a set of thirteen rules (numbered zero to twelve) proposed by Edgar Frank “Ted” Codd (August 23, 1923 – April 18, 2003) was a British computer scientist who, while working for IBM, invented the relational model for database management, the theoretical basis for relational databases. He made other valuable contributions to computer science, but the relational model, a very influential general theory of data management, remains his most memorable achievement. Edgar F. Codd, a pioneer of the relational model for databases, designed to define what is required from a database management system in order for it to be considered relational, i.e., an RDBMS., Codd produced these rules as part of a personal campaign to prevent his vision of the relational database being diluted, as database vendors scrambled in the early 1980s to repackage existing products with a relational veneer. Rule 12 was particularly designed to counter such a positioning. In
