Relational databases use primary keys and foreign keys to establish relationships between different tables of data.
A primary key is a field or set of fields in a database table that uniquely identifies each record in the table. Primary keys are used to ensure that each record in a table is unique and can be easily identified.
A foreign key is a field or set of fields in a database table that refers to the primary key of another table. Foreign keys are used to establish relationships between tables, allowing data from multiple tables to be linked and queried together.
Here’s an example to illustrate how primary keys and foreign keys work:
Imagine you have a database with two tables: a “Customers” table and an “Orders” table. The “Customers” table contains information about each customer, such as their name, address, and phone number. The “Orders” table contains information about each order, such as the order number, the customer who placed the order, and the items in the order.
In this case, the “Customer ID” field in the “Customers” table could be used as the primary key, and the “Customer ID” field in the “Orders” table could be used as the foreign key. This would establish a relationship between the two tables, allowing you to link customer information with order information.
Overall, primary keys and foreign keys are important in relational databases because they allow data from multiple tables to be linked and queried together, enabling more powerful and flexible data analysis and reporting.
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