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A foreign key is generally a primary key from one table that appears as a field in another where the first table has a relationship to the second. In other words, if we had a table A with a primary key X
12 lis 2023 · In this article we have learned about foreign key in DBMS. To summarize the article, a foreign key establishes relationship between tables and ensures consistency and integrity of data . It is applied to a column of one table which references the primary key of a column in another table.
A foreign key is a column (or group of columns) used in a relational database to link data between tables. This tutorial will introduce you to foreign keys and show you how to use them in SQL.
Foreign key constraint: Value in one relation must appear in another.
14 lis 2011 · Foreign key - a foreign key (FK) is a field or group of fields in a database record that points to a key field or group of fields forming a key of another database record in some (usually different) table. Usually a foreign key in one table refers to the primary key (PK) of another table.
Example: {ID} is a candidate key for Instructor One of the candidate keys is selected to be the primary key. Which one? Foreign key constraint: Value in one relation must appear in another Referencing relation Referenced relation Example: dept_name in instructor is a foreign key from instructor referencing department
The FOREIGN KEY constraint is used to prevent actions that would destroy links between tables. A FOREIGN KEY is a field (or collection of fields) in one table, that refers to the PRIMARY KEY in another table.
