Question

Why is Primary key necessary in a table​

Answer 1

Answer:

Every table can have (but does not have to have) a primary key. The column or columns defined as the primary key ensure uniqueness in the table; no two rows can have the same key. The primary key of one table may also help to identify records in other tables, and be part of the second table's primary key.

Explanation:

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Answer 2

Answer:

1) the matching fields are the primary key from one table that uniquely and definitions each record in a table

2) A Foreign key is a column in one table that must match the primary key of another table