Which two columns do all bridge tables contain?

A bridge table in a database is designed to resolve many-to-many relationships between different entities. To facilitate this, all bridge tables typically include a combination key, which serves as a surrogate primary key that uniquely identifies each record in the table, linking the two entities. This combo key is essential for efficiently querying and ensuring the integrity of relationships between the tables.

In addition to the combo key, bridge tables also contain a lookup column. This column is used to associate the records in the bridge table with the relevant entities in the associated tables, providing context and reference for the relationships. Essentially, the lookup column allows the bridge table to connect with dimensions or facts in other tables.

This structure is critical for maintaining the relational integrity of the database, ensuring that the data can be retrieved and linked appropriately across different tables. When analyzing complex relationships, this combination of a combo key and a lookup column is vital for effective data organization and retrieval. Therefore, this answer accurately reflects the fundamental characteristics of bridge tables in a data model.