Word
unique constraint
Definition
compound. a rule in a database that makes sure no two items in a list have the same information. For example, it prevents two different people from having the same email address in a system.
compound. a database rule that ensures all values in a specific column or set of columns are distinct from one another. It prevents duplicate entries while allowing for null values, depending on the specific database engine's implementation.
Examples
“The system uses a unique constraint to prevent duplicate usernames.”
“When designing the customer table, the developer added a unique constraint to the tax ID column to ensure no two clients share the same number.”
“Implementing a unique constraint at the database level provides a final layer of data integrity that prevents race conditions from creating duplicate records during high-traffic periods.”
Examples
simple
“The system uses a unique constraint to prevent duplicate usernames.”
contextual
“When designing the customer table, the developer added a unique constraint to the tax ID column to ensure no two clients share the same number.”
complex
“Implementing a unique constraint at the database level provides a final layer of data integrity that prevents race conditions from creating duplicate records during high-traffic periods.”
Usage
Commonly used in the context of SQL and relational database design; often applied to columns that serve as natural keys.
Etymology
A compositional term formed from the Latin unicus, meaning single or sole, and the Old French constrainte, derived from constringere, to bind together.
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.
Domain
Scan code
englishreference.com/q/unique-constraint