Code Rule E.F. Coded
E.F. Coded was a computer scientist who invented a relational model for database management. Based on the relative model, the relation database was created.
In the context of the 12 coded rules, 13 coded rules were proposed, which were to check DBMS's concept against its respective model.
Code rules really define what quality DBMS needs to become a Ribbing Database Management System (RDBMS).
This rule states that for a system to qualify as RDBMS, it should be able to manage the database completely by the relational capabilities.
Rule 1: Information Rule
All information (including metadata) is presented as tables stored in tables of cells. These rows and columns should be strictly unauthorized.
Rule 2: Guaranteed Access
Each unique piece of data (atomic value) should be: Table name + primary key (rows) + extras (columns).
Rule 3: Neutral of Symmetric Treatment
Null has many meanings, that means missing data, is not applicable or no value. It should be constantly controlled by the primary key should not be null. NULL must deliver the expression null.
Rule 4: Active Online Catalog
The description of the database dictionary (catalog) database must be. Catalogs powered by the same rule as the rest of the database. Similar query language used in the list on application databases.
Rule 5: Powerful Language
There should be a well-defined language to provide all the information in the information. Example: SQL can be accessed in any way other than the File Accessory Table SQL interface, then violation of this rule.
Rule 6: See Updating Rule
See all that is ideologically correct, it should be improved by the system.
Rule 7: Relative level operation
Enter, delete, and perform operations on every level of relationships. It should also be supported to set up operations like union, incision and teens.
Rule 8: Physical Data Freedom
The physical collection of data should not have any effect on the system. If say, some file assistant table has been renamed or moved from one disk to another, it will not affect the application.
Rule 9: Logical Data Independence
The user's view of the data should not change if there is a change in the database's logical structure (table structures). Say if the table is divided into two tables, then a new visual result should be given as attachments for two tables. This rule is the most difficult to satisfy.
Rule 10: Freedom of Integrity
Databases should be able to admit their own integrity instead of using other programs. Keys and check parameters, triggers etc. should be stored in the data dictionary. It also creates independent RDBMS from the front-end.
Rule 11: Distribution Freedom
It should work properly on the database network, regardless of its distribution. This distributes the foundation of the database.
Rule 12: Noncussession rule
If the lower level access is allowed in the system, then it should not be able to spoil or bypass the integrity rule to change the data. This can be achieved by some sort of search or encryption.
