Q.Explain the characteristics of relational database table.
Ans.
A
relation or table is the basis of a relational database management
system. The properties of characteristics of relations are as follows:No Duplicate Rows Exist.
There should not be two identical rows in a table. There must be at least one column or set of columns whose values uniquely identify each row in the table. Such column or set of columns is called primary key. This property ensures that every row in a table can be identified by specifying the primary key value.
The Order of Rows is Insignificant
The position of a row in a relation is insignificant. A row is not identified by its location in the relation. The rows can be retrieved in any order. It enables many users to share the same table without the concern of how the table is organized.
The Order of Columns is Insignificant
The position of a column in a relation is insignificant. A column is not identified by its location in the relation. It is referenced by its name. The columns can be retrieved in any order. It enables many users to share same table without the concern of how the table is organized.
Columns/Attributes are all Elemental or Atomic
An entry at the intersection of each row and column is atomic. A value that cannot be divided further is called atomic value.