Relational Model

The relational model is the theoretical foundation of relational databases - it represents data as a collection of tables (called relations), where each table consists of rows (tuples) and columns (attributes).

Key Concepts

• Relation (Table) - a collection of related data organized in rows and columns
• Tuple (Row) - a single record in a table
• Attribute (Column) - a named property that every row in the table has
• Primary Key - a column (or set of columns) that uniquely identifies each row
• Foreign Key - a column that references the primary key of another table, linking the two together

Example

-- customers table
customer_id | first_name | city
1           | Riya       | Noida
2           | Aman       | Delhi

-- orders table
order_id | customer_id | amount
101      | 1           | 2500
102      | 2           | 1800

Here, customer_id in the orders table is a foreign key referencing the customers table - this relationship is what gives the "relational" model its name.