addBatch

addBatch is a method in the JDBC API used to accumulate SQL commands for batch execution. It is provided by the java.sql.Statement and java.sql.PreparedStatement interfaces. With Statement, each call to addBatch adds a complete SQL command to the current batch; with PreparedStatement, you bind parameters for the current statement and call addBatch to add that parameterized instance to the batch.

Execution is triggered by executeBatch(), which sends all batched statements to the database in a single round trip. The method returns an array of update counts corresponding to each command in the batch. If a statement in the batch fails, a BatchUpdateException is thrown; the exception contains an updateCounts array indicating how many rows were affected up to the point of failure. After execution, clearBatch() can be used to reset the batch.

Best practices: use addBatch when performing many similar INSERT/UPDATE/DELETE operations to reduce round trips. Keep batch sizes manageable; the optimal size depends on the driver and database. Ensure proper transaction handling, especially with auto-commit off. Some database drivers support large or unlimited batch sizes, while others impose limits. Parameterized batching (PreparedStatement) is typically preferred for type safety and performance.

Notes: not all statements or databases support batching; check driver documentation. Batch updates can improve throughput but may complicate error handling and rollback. Update counts and exception handling may vary by driver, so testing is recommended when enabling batch processing in production.