Question

What are the more common types of SQL constraint and what do they mean?

a. Primary Key - Ensures uniqueness; Foreign Key - Ensures referential integrity
b. Index - Enhances data retrieval speed; Trigger - Executes predefined actions
c. Query - Retrieves information; View - Displays data subsets
d. Procedure - Performs specific tasks; Function - Produces calculated results

Answer 1

The common types of SQL constraints include Primary Key, ensuring uniqueness and non-null values, and Foreign Key, whichmaintains referential integrity between tables.

Step-by-step explanation:

The more common types of SQL constraints are a. Primary Key - Ensures that each row in a database table is unique and not null; b. Foreign Key - Ensures referential integrity by linking columns from one table to those of another, ensuring that the referenced data exists.

The difference between constraints and criterion in design is that constraints are conditions that must be met, while criteria are measurable values used to compare different designs. In databases, constraints ensure data integrity and enforce rules essential for the relationship between tables and data within them.