A foreign key is a field (or collection of fields) in one table that uniquely identifies a row of another table, establishing a link between them.
Questions & Step-by-step Solutions
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Q
Q: In a relational database, what is a foreign key?
Solution: A foreign key is a field (or collection of fields) in one table that uniquely identifies a row of another table, establishing a link between them.
Steps: 5
Step 1: Understand that a database is like a collection of tables, similar to a spreadsheet with rows and columns.
Step 2: Each table can have its own unique identifier for each row, called a primary key.
Step 3: A foreign key is a special field in one table that refers to the primary key in another table.
Step 4: This creates a connection or link between the two tables, allowing you to relate data from one table to another.
Step 5: For example, if you have a 'Customers' table and an 'Orders' table, the 'Orders' table can have a foreign key that links to the 'Customers' table to show which customer made each order.
