Relational Databases :
In relational databases, the relationship between data files is relational. Hierarchical and network databases require the user to pass a hierarchy in order to access needed data. These databases connect to the data in different files by using common data numbers or a key field. Data in relational databases is stored in different access control tables, each having a key field that mainly identifies each row. In the relational databases are more reliable than either the hierarchical or network database structures. In relational databases, tables or files filled up with data are called relations (tuples) designates a row or record, and columns are referred to as attributes or fields.
Relational databases work on each table has a key field that uniquely indicates each row, and that these key fields can be used to connect one table of data to another.
The relational database has two major reasons:
- Relational databases can be used with little or no training.
- Database entries can be modified without specify the entire body.
Properties of Relational Tables:
In the relational database we have to follow some properties which are given below.
- It's Values are Atomic
- In Each Row is alone.
- Column Values are of the Same thing.
- Columns is undistinguished.
- Sequence of Rows is Insignificant.
- Each Column has a common Name.
source
http://www.c-sharpcorner.com/uploadfile/65fc13/types-of-database-management-systems/