Nov 15, 2025 · A primary key is a unique identifier assigned to each record within a database table. A primary key is an attribute (or column) or a set of attributes that uniquely identifies …

In the relational model of databases, a primary key is a designated set of attributes (column (s)) that can reliably identify and distinguish between each individual record in a table.

SQL PRIMARY KEY Constraint The PRIMARY KEY constraint is used to uniquely identify each record in a table. Primary keys must contain unique values, and cannot contain NULL values. …

A primary key is a column (s) within a relational database table that uniquely represents each record in the table. For example, the ideal primary key for a table of students would be their ID …

A primary key is a column or columns in a database table with values that uniquely identify each row or record.

Oct 22, 2020 · In SQL databases, a primary key is a unique identifier for each table row; it does not allow duplicate or NULL values and guarantees the distinctness of each row in that table.

Oct 25, 2022 · A primary key, also called a primary keyword, is a column in a relational database table that's distinctive for each record. It's a unique identifier, such as a driver's license …

Aug 7, 2025 · Understand what an SQL primary key is and its function in database relationships and query performance in this technical tutorial.

Jun 28, 2025 · In database terms, a primary key is a column (or a group of columns) in a table that uniquely identifies each row. Think of it as a unique ID assigned to every record in a table …

A primary key uniquely identifies each record in a table. Databases use primary keys to compare, sort, and store records, and to create relationships between records.