Multiquery

Multiquery is a database interaction technique in which multiple SQL statements are sent to a database in a single request, with the client library processing the resulting multiple result sets. This approach is supported by several database drivers and APIs that allow batch execution of statements, making it possible to orchestrate several operations without issuing separate round-trips for each statement.

In practice, multiquery is commonly associated with MySQL and its client libraries, where a single string containing several statements separated by semicolons can be executed together. After execution, the client retrieves each result set in order, using routines provided by the API to advance to the next result. Errors can occur on any statement within the batch, and handling them requires careful error management across all statements in the sequence. Some drivers enable or disable multiquery via configuration due to security considerations and compatibility concerns.

Benefits of multiquery include reduced network latency from fewer round-trips and improved throughput for sequences of related statements. It can also simplify code in scenarios where multiple operations must be performed in close succession. However, it carries risks and limitations: error handling becomes more complex, drivers may enforce limits on the number of statements, and concatenating user input can increase SQL injection risk unless properly parameterized or sanitized. Additionally, multiquery does not guarantee atomicity; to ensure transactional integrity, statements should be wrapped in an explicit transaction when supported.

Alternatives and related concepts include prepared statements with batching, bulk operations, and standard transactional control using separate or batched statements. See also batching, transactions, and result set processing.