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Everything about Check constraint
Type of integrity constraint in SQL
A check constraint is a type of integrity constraint in SQL which specifies a requirement that must be met by each row in a database table. The constraint must be a predicate. It can refer to a single column, or multiple columns of the table. The result of the predicate can be either TRUE, FALSE, or UNKNOWN, depending on the presence of NULLs. If the predicate evaluates to UNKNOWN, then the constraint is not violated and the row can be inserted or updated in the table. This is contrary to predicates in WHERE clauses in SELECT or UPDATE statements. Wikipedia →
🧭 Start here: a 6-step reading path
- Read the overview: Check constraintA 5-minute orientation
- Pick up a classic book: Abstraction, reformulation, and approximationThe most-reprinted book on the subject
- Read the landmark paper: SVP Inversion for Weakening Multibeam Bathymetry Errors by Constraint of Check Line DepthCited 10 times
- Go sideways: Foreign keyA closely related topic
- Go sideways: Referential integrityA closely related topic
📖 Definitions
No dictionary entry for this exact phrase.
🗂️ The subject at a glance
🏆 Landmark papers (most cited)
📚 Books worth reading
Abstraction, reformulation, and approximationSven Koenig, Robert C. Holte · 2002
Ranked by number of editions on Open Library, a rough measure of how lasting a book is.
🔗 Related topics
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