What term is used to describe a database field that allows relational tables to link to one another, but does not decessarily have to have unique values for all records?

Question: What term is used to describe a database field that allows relational tables to link to one another, but does not decessarily have to have unique values for all records?

The database field that allows relational tables to link to one another, but does not necessarily have to have unique values for all records, is called a **foreign key**.

A foreign key is a column in a table that references the primary key of another table. This allows you to create relationships between tables, which can be used to store data more efficiently and to query and report on data more easily.

For example, you might have a `Customers` table with a primary key column called `customer_id`. You might also have an `Orders` table with a foreign key column called `customer_id`. This would allow you to link each order to a specific customer.

Foreign keys can be either nullable or non-nullable. A nullable foreign key can contain null values, while a non-nullable foreign key cannot contain null values.

Nullable foreign keys are often used to model one-to-many relationships. For example, a customer can place multiple orders, but an order can only belong to one customer. In this case, the `customer_id` foreign key in the `Orders` table would be nullable.

Non-nullable foreign keys are often used to model many-to-one relationships. For example, a product can be in multiple categories, but a category can only contain products. In this case, the `category_id` foreign key in the `Products` table would be non-nullable.

Foreign keys are a powerful tool for creating and managing relational databases. By using foreign keys, you can store data more efficiently, query and report on data more easily, and maintain the integrity of your data.

Rjwala

Rjwala is your freely Ai Social Learning Platform. here our team solve your academic problems daily.