Relational Model
The relational data model retrieves information from a collection of tables and returns that information to the user as one table. Just use the table name(s) to get the table(s) that you want. Relationships between data contained in multiple tables is done by matching data values.
The relational model of data was refined in 1969-1970 by Dr. E.F. Codd. His Relational DataBase Management System (RDBMS) consisted of:
No database system supports the relational model completely, but most implementations are a close match. All data is represented in a two-dimensional table and, for that reason, it is very easy to work with. All data is in tables including the application data tables, index tables, database and creation information, control and security, table statistics, program SQL statements, etc. All but the program SQL statements may be retained by you using SQL SELECT statements so that you can see how the database works.SELECT statements so that you can see how the database works.

