CODEWITHSUNDEEP
databaserelational-database
mhrzn
mhrzn

Reputation: 389

Does a relation(table) without a primary key qualify as a proper relation?

What if the table does not have a primary key ? Or Does does the table need to enforce Entity Integrity to be called as a relation?

One of the Relation properties states that :

Each row(tuple) must be distinct. (does this means that the table must have a primary key)

Upvotes: 1

Views: 702

Answers (1)

nvogel
nvogel

Reputation: 25534

A relation does not have duplicate tuples. A relational table therefore has to have that property as well. If tuple uniqueness is enforced in a table that means the table has at least one candidate key, even if the key is the entire set of attributes in the table.

In the relational model there are really no "primary" keys as such because all keys are effectively equal in form, function and status. Since a primary key is just any arbitrarily selected one of the keys in a table, we can say that any table with at least one key has by definition satisfied the primary key requirement.

Upvotes: 3

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