A primary key constraint is also called
Correct answer: A. Integrity constraint
- A. Integrity constraint
- B. Redundancy constraint
- C. Referential integrity constraint
- D. Entity integrity constraint
Explanation
A primary key constraint is a type of integrity constraint applied to a relational database table. It enforces two key rules:Uniqueness: Each row in the table must have a unique value for the primary key column(s). No two rows can have the same primary key value.Not Null: The primary key column(s) cannot contain null values. Every row must have a value for the primary key.These rules ensure that each row in the table can be uniquely identified and that there are no missing values for the primary key attribute(s). This helps to maintain data consistency and simplifies data retrieval in the database
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Databases cover tables, records, fields, keys and relationships, together with database management systems and relational database design. The subject includes primary and foreign keys, normalization, SQL commands such as SELECT, INSERT, UPDATE and DELETE, queries, forms and reports, while distinguishing a database from a spreadsheet used for simple tabular data.
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