FUNDAMENTALS OF COMPUTER

Detailed explanation-1: -In a foreign key reference, a link is created between two tables when the column or columns that hold the primary key value for one table are referenced by the column or columns in another table. This column becomes a foreign key in the second table.

Detailed explanation-2: -A FOREIGN KEY is a field (or collection of fields) in one table, that refers to the PRIMARY KEY in another table. The table with the foreign key is called the child table, and the table with the primary key is called the referenced or parent table.

Detailed explanation-3: -A table relationship works by matching data in key fields-often a field with the same name in both tables. In most cases, these matching fields are the primary key from one table, which provides a unique identifier for each record, and a foreign key in the other table.

Detailed explanation-4: -A foreign key is an attribute that completes a relationship by identifying the parent entity. Foreign keys provide a method for maintaining integrity in the data (called referential integrity) and for navigating between different instances of an entity.

Detailed explanation-5: -In SQL, we can create a relationship between two tables using the FOREIGN KEY constraint. Here, the customer id field in the Orders table is FOREIGN KEY which references the id field in the Customers table.