New Features¶ ↑

• Dataset#merge and related merge_* methods have been added for the MERGE statement. MERGE is supported on PostgreSQL 15+, Oracle, Microsoft SQL Server, DB2, H2, HSQLDB, and Derby. You can use MERGE to insert, update, and/or delete in a single query. You call the merge_* methods to setup the MERGE statement, and merge to execute it on the database:

  ds = DB[:m1]
    merge_using(:m2, i1: :i2).
    merge_insert(i1: :i2, a: Sequel[:b]+11).
    merge_delete{a > 30}.
    merge_update(i1: Sequel[:i1]+:i2+10, a: Sequel[:a]+:b+20)
  
  ds.merge
  # MERGE INTO m1 USING m2 ON (i1 = i2)
  # WHEN NOT MATCHED THEN INSERT (i1, a) VALUES (i2, (b + 11))
  # WHEN MATCHED AND (a > 30) THEN DELETE
  # WHEN MATCHED THEN UPDATE SET i1 = (i1 + i2 + 10), a = (a + b + 20)
  

  On PostgreSQL, the following additional MERGE related methods are available:

  • merge_do_nothing_when_matched

  • merge_do_nothing_when_not_matched

• A :disable_split_materialized Database option is now supported on MySQL. This disables split_materialized support in the optimizer, working around a bug in MariaDB 10.5+ that causes failures in Sequel’s association tests.