The DataSet class exists in the System.Data namespace.
| DataSet Class | Description |
| DataTable | It is defined in the System.Data namespace and represents a single table of memory-resident data. It contains a collection of columns represented by a DataColumnCollection. Constraints represented by a ConstraintCollection. It also contains a collection of rows represented by the DataRowCollection. |
| DataColumn | Relationships can be built with more than one column per table by specifying an array of DataColumn objects as the key columns. |
| DataRow | It retains both its current and original versions to identify changes to the values stored in the row. |
| Constraint | It adds a UniqueKeyConstraint or a ForeignKeyConstraint to enforce an integrity constraints when changes are made to the related column values. |
| DataRelation | It identifies matching columns in two tables of a DataSet. |
