Support alter_table rename_constraint on PostgreSQL 9.2+

Author: jeremyevans

CHANGELOG

@@ -1,5 +1,7 @@
 === master
 
+* Support alter_table rename_constraint on PostgreSQL 9.2+ (jeremyevans) (#2274)
+
 * Do not auto parameterize PostgreSQL range and multirange types containing expressions (jeremyevans)
 
 * Support sort and reverse methods in pg_array_ops extension on PostgreSQL 18+ (jeremyevans)

lib/sequel/adapters/shared/postgres.rb

@@ -154,6 +154,11 @@ def alter_constraint(name, opts=OPTS)
  @operations << {:op => :alter_constraint, :name => name}.merge!(opts)
  end
 
+ # :inherit :: Set true to use INHERIT, or false to use NO INHERIT (PostgreSQL 18+)
+ def rename_constraint(name, new_name)
+ @operations << {:op => :rename_constraint, :name => name, :new_name => new_name}
+ end
+
  # Validate the constraint with the given name, which should have
  # been added previously with NOT VALID.
  def validate_constraint(name)
@@ -1210,6 +1215,10 @@ def alter_table_generator_class
  Postgres::AlterTableGenerator
  end
 
+ def alter_table_rename_constraint_sql(table, op)
+ "RENAME CONSTRAINT #{quote_identifier(op[:name])} TO #{quote_identifier(op[:new_name])}"
+ end
+
  def alter_table_set_column_type_sql(table, op)
  s = super
  if using = op[:using]

spec/adapters/postgres_spec.rb

@@ -1514,6 +1514,13 @@ def before_create
  @db.alter_table(:atest){alter_constraint(:atest_nn, :inherit=>false)}
  end if DB.server_version >= 180000
 
+ it "should support renaming constraints" do
+ @db.create_table!(:atest){Integer :i; constraint(:foo){i > 0}}
+ @db.check_constraints(:atest).keys.must_equal [:foo]
+ @db.alter_table(:atest){rename_constraint(:foo, :bar)}
+ @db.check_constraints(:atest).keys.must_equal [:bar]
+ end if DB.server_version >= 90200
+
  it "should support :using when altering a column's type" do
  @db.create_table!(:atest){Integer :t}
  @db[:atest].insert(1262404000)