The term RDBMS stands for Relational Database Management System.
All new modern database management systems like SQL, MS SQL Server,IBM DB2, Oracle, MS-Access and My-SQL are based on RDBMS.
In RDBMS the term relational model was introduced by E.F. Codd.
At 1970 to 1972, E.F. Codd published a paper to use relational database model.
RDBMS is generally based on the concept of E.F. Codd's relational model invention.
The table is collection of related data entries and contains rows and coloumn to store the data.The RDBMS use the tables to store the data.
A row is a part of table and it is called record.It conntain a specific entry in the table.This is horizontal entry in the table.
A column is a vertical entity in the table that contains all specific information in a field of a table. For example E_PROFILE in above table which contains all information regarding all employee in profile.
Field is small entity in a table which consists information about every record in a table.In the above example employee table contain e_id,e_name,e_age and e_profile.
Null values in a table defines that the field has been left blank during the record insertion or creation. It is very different from the value that filled with zero or a field of Space.