Mysql Foreign Key

Mysql foreign key. The following sql creates a foreign key on the personid column when the orders table is created. A foreign key is a key used to link two tables together. The table containing the foreign key is called the child table and the table containing the candidate key is called the referenced or parent table. It means a foreign key field in one table refers to the primary key field of the other table.

Cara membuat foreign key di mysql phpmyadmin dengan mudah adalah proses menambahkan relasi antara tabel tabel yang telah dibuat pada sebuah database mysql berdasarkan primary key. It is also known as the referencing key. For storage engines other than innodb it is possible when defining a column to use a references tbl name col name clause which has no actual effect and serves only as a memo or comment. What is foreign key in mysql.

Foreign key atau kunci tamu merupakan primary key pada tabel satu yang kemudian dijadikan key juga di tabel lainnya dan bisa lebih dari satu tabel. Sebuah tabel dikatakan child bila memiliki suatu field yang merupakan reference terhadap key di tabel parent. Here is the basic syntax of defining a foreign key constraint in the create table or alter table statement. Foreign key digunakan untuk menandai suatu tabel terhubung dengan tabel lain dalam konteks tabel parent dan child.

Mysql foreign key syntax. Mysql alter table employee table add constraint fk department id foreign key department id references department table department id. Advantage of foreign key. The foreign key is used to link one or more than one table together.

Query ok 0 rows affected 2 82 sec records. A foreign key relationship involves a parent table that holds the initial column values and a child table with column values that reference the parent column values. What s the use of foreign key constraint in a mysql. In mysql innodb tables support checking of foreign key constraints.

The foreign key on the column reportto is known as a recursive or self referencing foreign key. See the innodb storage engine and foreign key constraint differences. Sql foreign key constraint. Hal ini digunakan untuk menjaga konsistensi dan keterkaitan antar tabel.

A foreign key matches the primary key field of another table. How to create a foreign key in mysql. In this tutorial you ll learn about foreign key constraint and it s advantages. Cara membuat foreign key di mysql.

The foreign key constraint is a key used to link two tables together. A foreign key is a field or collection of fields in one table that refers to the primary key in another table.