Põhivõtmeteks

Põhivõtmeteks, also known as primary keys in English, are a fundamental concept in database design and relational database management systems. A primary key is a column or a set of columns in a table that uniquely identifies each row in that table. The primary key constraint ensures that the values in the primary key column(s) are unique and not null, thereby maintaining the integrity and reliability of the data.

Primary keys play a crucial role in establishing relationships between tables in a relational database. They are often used as foreign keys in other tables to create links between related data. This helps in maintaining data consistency and enables efficient data retrieval and manipulation.

When designing a database, it is essential to choose primary keys carefully. The chosen primary key should be a value that is unique and immutable for each record. Common examples of primary keys include social security numbers, student IDs, and product serial numbers. In some cases, surrogate keys, such as auto-incrementing integers, are used when a natural key (a key that exists in the real world) is not available or not suitable.

In summary, primary keys are essential for ensuring data integrity, maintaining relationships between tables, and facilitating efficient data management in relational databases. Proper selection and implementation of primary keys are critical for the overall performance and reliability of a database system.