What is a FOREIGN KEY constraint?
Are you preparing for IT certification? With practice questions, study notes, interactive quizzes, tips and technical articles, uCertify PrepKits ensure that you get a solid grasp of core technical concepts to ace your certification exam in first attempt.
What is a FOREIGN KEY constraint?
Rating:
A FOREIGN KEY constraint (also known as referential integrity constraint) specifies that each value in a specified column or set of columns must match a value in another table's unique or primary key (column or set of columns protected by a UNIQUE or PRIMARY KEY constraint). A column or set of columns protected by a FOREIGN KEY constraint is known as a foreign key. A table having a foreign key is called child table. A table having a unique or primary key referenced by a foreign key is called parent table. A table's foreign key can reference to the same table's unique or primary key. A foreign key can contain duplicate and NULL values.
Rating:
Was this information helpful?
Other articles
- What are trace files?
- What is a business service layer in the MSF application model?
- What are articles?
- What is merge replication?
- What is waterfall approach?