EF Codd’s Rules in DBMS

Rule 6: View updation rule 

• Difference views created for different purposes should be automatically updated by the system itself.

Rule 7: Relational level operation 

• Operations like  insert, delete and update operations must be supported at each level of relation even though it might be a nested relation or a complex relation 
• Set operations like union, intersection, minus must be supported.

Rule 8: Physical data independence 

• Any change in the physical location of the table should not reflect the change at the application level 
• Example: If you rename or move a file from one disk to another then it should not affect the application.

Rule 9: Logical data independence 

• If there are any changes done to the logical structure of the database table, then users view of data should not be changed
• If  the table is split into two tables, then a new view should give result as the join of these two tables but this rule is very difficult to satisfy.

Rule 10: Integrity  independence 

• Database table should design itself on integrity rather than using external programs.
• It should use primary keys, check constants triggers, etc which makes our DBMS independent of the front end application.

Rule 11: Distribution Independence 

• Data distribution over various geographical locations over a network should not reflect the end-user i.e  you should feel that all the data is stored in a single place 
• This rule laid the foundation for the distributed database.

Rule 12: Non-Subversion Rule 

• Any access given to the data that is present in the lowest level must not give a chance to authenticate constraints and change data ,this can be achieved through some kind of encryption techniques.