diff --git a/activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb b/activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb index e5f4d6f5fb667..07b42269cce6c 100644 --- a/activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb +++ b/activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb @@ -572,6 +572,13 @@ def show_variable(name) # Returns a table's primary key and belonging sequence. def pk_and_sequence_for(table) + execute_and_free("DESCRIBE #{quote_table_name(table)}", 'SCHEMA') do |result| + keys = each_hash(result).select { |row| row[:Key] == 'PRI' }.map { |row| row[:Field] } + keys.length == 1 ? [keys.first, nil] : nil + end + end + + def detailed_pk_and_sequence_for(table) #:nodoc: keys = [] sql = <<-SQL SELECT t.constraint_type, k.column_name diff --git a/activerecord/lib/active_record/connection_adapters/mysql_adapter.rb b/activerecord/lib/active_record/connection_adapters/mysql_adapter.rb index 42fe1df3ae5c9..5751f6c33c75e 100644 --- a/activerecord/lib/active_record/connection_adapters/mysql_adapter.rb +++ b/activerecord/lib/active_record/connection_adapters/mysql_adapter.rb @@ -755,6 +755,13 @@ def show_variable(name) # Returns a table's primary key and belonging sequence. def pk_and_sequence_for(table) #:nodoc: + execute_and_free("DESCRIBE #{quote_table_name(table)}", 'SCHEMA') do |result| + keys = each_hash(result).select { |row| row[:Key] == 'PRI' }.map { |row| row[:Field] } + keys.length == 1 ? [keys.first, nil] : nil + end + end + + def detailed_pk_and_sequence_for(table) #:nodoc: keys = [] sql = <<-SQL SELECT t.constraint_type, k.column_name diff --git a/activerecord/lib/active_record/schema_dumper.rb b/activerecord/lib/active_record/schema_dumper.rb index 92a83a50765d9..dd079c797d8f9 100644 --- a/activerecord/lib/active_record/schema_dumper.rb +++ b/activerecord/lib/active_record/schema_dumper.rb @@ -86,7 +86,9 @@ def table(table, stream) tbl = StringIO.new # first dump primary key column - if @connection.respond_to?(:pk_and_sequence_for) + if @connection.respond_to?(:detailed_pk_and_sequence_for) + pk, _ = @connection.detailed_pk_and_sequence_for(table) + elsif @connection.respond_to?(:pk_and_sequence_for) pk, _ = @connection.pk_and_sequence_for(table) elsif @connection.respond_to?(:primary_key) pk = @connection.primary_key(table)