Primary Key vs Unique Constraint in PostgreSQL
The primary key and unique constraint are important concepts in PostgreSQL that help ensure data integrity and uniqueness in tables.
Primary Key
The PRIMARY KEY constraint in PostgreSQL is used to uniquely identify each record in a table. It ensures that each value in the specified column(s) is unique and not null. By default, a primary key also creates a unique index on the column(s) to enforce uniqueness and faster data retrieval.
Unique Constraint
The UNIQUE constraint in PostgreSQL also ensures the uniqueness of values within a column or a group of columns. However, unlike the primary key, a table can have multiple unique constraints, and the unique constraint does not automatically create a corresponding index.
Focus Keyword: PostgreSQL PRIMARY KEY vs UNIQUE Constraint
In summary, the primary key is used to uniquely identify each record in a table and automatically creates a unique index, while the unique constraint ensures uniqueness but does not necessarily create an index.
Please login or Register to submit your answer