SQL Archives - Web Development

Category: SQL

What is Primary Key in SQL

What is a Primary Key? The PRIMARY KEY constraint uniquely identifies each row in a table. It must contain UNIQUE values and has an implicit NOT NULL constraint. A table in SQL is strictly restricted to have one and only one primary key, which is comprised of single or multiple fields (columns). The PRIMARY KEY…

Read the full article

What is Sql – Constraints

What is Sql – Constraints Constraints are utilized to indicate the principles concerning information in the table. It tends to be connected for single or different fields in a SQL table during the formation of a table or in the wake of making utilizing the ALTER TABLE direction. The imperatives are: NOT NULL – Not…

Read the full article