A primary key isa designated attribute that can reliably identify and distinguish each record in a table.Learn about natural keys, surrogate keys, alternate keys, and how to define primary keys in SQL. Sep 21, 2021 ·What is aprimarykey? In the world of databases, theprimarykeyof a relational table uniquely identifies each record in the table. Databases use keys to compare, sort, and store records, and to create relationships between records. Choosing theprimarykeyin a database is one of the most important steps in the process. SQLPRIMARY KEYConstraint ThePRIMARY KEYconstraint is used to uniquely identify each record in a table.Primarykeys must contain unique values, and cannot contain NULL values. Each table can have only ONEprimarykey. Theprimarykeycan be a single column or a combination of columns. Jan 1, 2025 ·Aprimarykeyis a special relational database constraint that uniquely identifies each record in a table. You can think of it like a Social Security number for data.
