primærnøglekolonnen

A primærnøglekolonne, often translated as primary key column, is a fundamental concept in relational database design. It serves as a unique identifier for each record within a table. This means that the value in the primary key column must be distinct for every row, ensuring that no two records are identical. The primary key column is crucial for establishing relationships between different tables in a database. By referencing the primary key of one table in another table (as a foreign key), you can link related data.

The selection of a primary key column is an important design decision. Ideally, a primary key should be stable, meaning its value should not change over time. It should also be non-null, as a missing identifier would defeat its purpose. Often, a single column is sufficient to act as a primary key. However, in some cases, a combination of two or more columns might be needed to uniquely identify a record. This is known as a composite primary key. The integrity of the data within a database heavily relies on the correct implementation and maintenance of its primary key columns.