What is uq in mysql

Collectives on Stack Overflow. Learn more. Ask Question. Asked 11 years, 1 month ago. Active 2 years, 9 months ago. Viewed k times. Ivan Ivan There is a tooltip feature request at bugs. MySQL Workbench 6. Active Oldest Votes. Improve this answer. Vasiliy Kulakov Vasiliy Kulakov 5, 1 1 gold badge 18 18 silver badges 15 15 bronze badges. Ivan: A unique constraint ensures that a value can only ever exist in the column once.

Any attempt to add a duplicate will result in an unique data constraint error. The unique constraint as supports covering more than one column - this is called a composite. Ivan -- it is a way to help index values while preventing duplicates.

For example -- e-mail and SSN fields for a unique list of customers should be a unique index, since you frequently do lookups using those fields and they shouldn't repeat.

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Computer Graphics. Software Engineering. This checbox is read-only and symbolizes that the field is used by any association as owner field AI - Auto Increment. This checkbox sets if the specified field will be marked as Auto-Increment. It's useful only for primary keys. UQ - Unique. Welcome to the Skipper support forum.