Partnertabelle

Partnertabelle is a term used in database design to describe a table that models a many-to-many relationship between two other tables. In practice it is often called a junction or association table. The Partnertabelle stores pairs of related entities and may include additional attributes that describe the nature of the relationship.

Typically a Partnertabelle contains two foreign keys, each pointing to one of the related tables. For example, in a system with a Customer table and a Project table, a Partnertabelle might have customer_id and project_id as foreign keys. It can also include extra fields such as role (to denote the kind of partnership), start_date, end_date, status, or other attributes that describe the relationship. The primary key is often a composite of the two foreign keys, or a surrogate key may be used if additional attributes necessitate it.

A core purpose of the Partnertabelle is data normalization: it eliminates repetition by storing only the association in one place and relies on the related tables for entity data. This structure supports flexible queries to find all partners of an entity, all entities partnered with a given partner, and the characteristics of a specific partnership. Data integrity is maintained with foreign key constraints, and performance can be improved through appropriate indexing on the foreign keys and any frequently queried attributes like role or dates.

Common use cases include customer–project associations, supplier–product relationships, student–course enrollments, and many other scenarios where two entities can relate in multiple ways. Design choices—such as whether to include a surrogate key, how to model roles, and how to handle historical data—depend on the domain requirements and query patterns.