RDBMS

 RDBMS is relational database management system which is provide a relational mode between data tables.
It is a suite of software programs for creating, modifying and manipulating a relational database.
Dr.E F Codd was unhappy with the DBMSs available in those days handled large volume of data.He presented his paper titled "A Relational Mode Of Data for  large Shared Databanks".It is based on two  branches of mathematics - 'Set Theory' and 'Order Predicate Logic'.
It has 12 Rules :-

1. All information represented only in tables.
2. Each atomic value is accessible by combination of table name, primary key and column name.
     >>  No duplicates. 
3. Systematic treatment of NULLs.
4. Line data catalog maintained.
    >> Accessible in same way as ordinary data.
5. Comprehensive data sub-language.
    >>   Data definitions.
    >>   View definitions.
    >>   Data manipulation.
    >>   Integrity constrains.
    >>   Authorization.
    >>   Transaction boundaries.
6. View updated correctly.
7. High-level Insert, Update, Delete.
8. Physical data independence.
9. Logical data independence.
10.Integrity independence.
     >> Not in application program.
     >> Semantic integrity a near-impossibility here.
11.Distribution independence.
12.Non-Subversion.
     >> Low-level Language can't subvert to bypass high-level language.