What is the term for withdrawing information from multiple relations?

The term for withdrawing information from multiple relations is a join. A join is a fundamental operation in relational databases that allows users to combine rows from two or more tables based on a related column between them. This operation is crucial for retrieving comprehensive data that resides in different tables, providing a way to consolidate relevant information for analysis or reporting.

Joins can take various forms such as inner joins, outer joins (left, right, full), and cross joins, each serving different purposes in how data is gathered. The ability to join tables effectively is essential for database management and understanding relationships within the data model.

In contrast, primary keys serve as unique identifiers for records within a single table, but do not facilitate the retrieval of information across multiple tables. Dicing refers to selecting a sub-cube from a data cube in data warehousing, and while querying is the broader act of requesting specific data from a database, it does not specifically denote the act of combining data from multiple relations. Therefore, a join is the precise term that encapsulates the merging of information from various relations in relational databases.