Question

Define and identify the primary key in the following table:

Table: Stationary

| _No | _Name | *_Qty | PurchaseDate |
| 101 | Pen | 102 | 2011-12-12 |
| 102 | Pencil | 201 | 2013-02-21 |
| 103 | Eraser | 90 | 2011-09-09 |
| 109 | Sharpener | 90 | 2012-08-31 |
| 113 | Clips | 900 | 2011-09-09 |

Answer 1

An attribute or set of attributes which are used to identify a tuple uniquely is known as Primary key.

Primary key: _No or _Name