Question

In a relational table for PURCHASE_RECEIPTS, what would be the primary key?

1) Receipt number (Rec_No)
2) Purchase date
3) Customer name
4) Product name

Answer 1

The primary key for a relational table for PURCHASE_RECEIPTS should be the Receipt number (Rec_No), as it uniquely identifies each purchase receipt record.

Step-by-step explanation:

In the context of a relational table for PURCHASE_RECEIPTS, the primary key is typically the attribute that can uniquely identify each record in the table. Of the options provided:

1. Receipt number (Rec_No)
2. Purchase date
3. Customer name
4. Product name

The most suitable choice for a primary key would be the Receipt number (Rec_No) because it is unique to each transaction. Purchase date, Customer name, and Product name are not good candidates for primary keys as they are not necessarily unique to each purchase; the same customer can make multiple purchases on the same date, and the same product can appear in multiple purchase receipts. In contrast, the Receipt number is designed to be unique for every transaction, ensuring that each record in the PURCHASE_RECEIPTS table is distinct and easily identifiable.