What is referential integrity in SQL?

Referential integrity refers to the relationship between tables. Referential integrity is the logical dependency of a foreign key on a primary key. The integrity of a row that contains a foreign key depends on the integrity of the row that it references—the row that contains the matching primary key.

What is referential integrity?

Referential integrity refers to the relationship between tables. Because each table in a database must have a primary key, this primary key can appear in other tables because of its relationship to data within those tables. When a primary key from one table appears in another table, it is called a foreign key .

Which table types are used for referential integrity?

An introduction to foreign keys and referential integrity in…

• Both tables must be of the InnoDB table type.
• The fields used in the foreign key relationship must be indexed.
• The fields used in the foreign key relationship must be similar in data type.

What is referential integrity constraint explain with example?

A foreign key constraint (also referred to as a referential constraint or a referential integrity constraint) is a logical rule about values in one or more columns in one or more tables. For example, a set of tables shares information about a corporation’s suppliers. Occasionally, a supplier’s name changes.

What is an example of referential integrity?

Referential integrity It means the reference from a row in one table to another table must be valid. Examples of referential integrity constraint in the Customer/Order database of the Company: Customer(CustID, CustName) Order(OrderID, CustID, OrderDate)

Which is an example of referential integrity?

What is Cascade update in a database?

The Cascade Update utility allows Administrators to maintain database integrity and consistency by altering or deleting the data in one or more dependent files to match changes made to data in a source file.

What is the use of on delete cascade in SQL?

Use the ON DELETE CASCADE option to specify whether you want rows deleted in a child table when corresponding rows are deleted in the parent table. If you do not specify cascading deletes, the default behavior of the database server prevents you from deleting data in a table if other tables reference it.

When should I use on delete cascade?

Why do we use Cascade?

CASCADE. It is used in conjunction with ON DELETE or ON UPDATE. It means that the child data is either deleted or updated when the parent data is deleted or updated.

What is on delete cascade?