What is a FOREIGN KEY ?

chinmay.sahoo

chinmay.sahoo

New member
A FOREIGN KEY constraint prevents any actions that would destroy links between tables with the Corresponding data keys. A simple way to think of a foreign key is that, essentially, it is another field which has a corresponding primary key field .

A foreign key in one table points to a primary key or unique key on another table. Foreign keys prevent actions that would change rows with foreign key values when there are no primary keys with that value. The foreign key constraints are used to enforce referential integrity
 
What’s the purpose / use of primary and foreign keys? Primary and foreign keys are a way in which the constrain associated data together to ensure data in your database stays consistent and to make sure no redundant data is in the database as a consequence of deleting a table or row in one table that disturbs data in other tables that may possibly rely on that information. It can cause both data integrity glitches as well as glitches with your application that uses such database.
 
A foreign key (FK) is a column or combination of columns that is used to establish and enforce a link between the data in two tables. You can create a foreign key by defining a FOREIGN KEY constraint when you create or modify a table.
 
A foreign key, also called a foreign keyword, in a database table is a key from another table that refers to (or targets) a specific key, usually the primary key , in the table being used. A primary key can be targeted by multiple foreign keys from other tables. But a primary key does not necessarily have to be the target of any foreign keys.
 
A foreign key (FK) is a column or combination of columns that is used to establish and enforce a link between the data in two tables. You can create a foreign key by defining a FOREIGN KEY constraint when you create or modify a table.
 
As others have mentioned a foreign key is used in relational databases and is function as a link between two tables, foreign keys (and primary keys) are used to ensure that there is no redundant data in a database.
 
In context of relational databases, a foreign key is a field (or collection of fields) in one table that uniquely identifies a row of another table. In simpler words, the foreign key is defined in a second table, but it refers to the primary key in the first table.
 
A foreign key is a column or group of columns in a relational database table that provides a link between data in two tables. It acts as a cross-reference between tables because it references the primary key of another table, thereby establishing a link between them.

Bulkmailstack
 
A foreign key is a field in one table that uniquely identifies a row of another table. In other words, the foreign key is defined in a second table, but it refers to the primary key in the first table.
 
A foreign key is a key used to link two tables together. This is sometimes called a referencing key.
Foreign Key is a column or a combination of columns whose values match a Primary Key in a different table.
 
You must log in or register to reply here.
Back
Top