Understanding table relationships
In a data model, relationships refer to the connections between different entities or tables within a database. There are three types of relationships in a data model: one-to-many, many-to-many, and one-to-one. Let’s discuss each type in detail along with some examples.
One-to-many relationship
In a one-to-many relationship, one record in a table is associated with multiple records in another table. This is the most common type of relationship in a database.
For example, a customer may place many orders, but each order is associated with only one customer. In this case, the customer table is on the one side of the relationship, and the order table is on many sides. The relationship is established by creating a foreign key in the order table that refers to the primary key in the customer table.
Another example is the relationship between a department table and an employee table. A department may have many employees, but each employee...