module ActiveRecord::ConnectionAdapters::PostgreSQL::DatabaseStatements - activerecord-4.2.4 Documentation

# module ActiveRecord::ConnectionAdapters::PostgreSQL::DatabaseStatements

### Public Instance Methods

begin_db_transaction() click to toggle source

Begins a transaction.

    # File lib/active_record/connection_adapters/postgresql/database_statements.rb, line 211
    def begin_db_transaction
      execute "BEGIN"
    end

begin_isolated_db_transaction(isolation) click to toggle source

    # File lib/active_record/connection_adapters/postgresql/database_statements.rb, line 215
    def begin_isolated_db_transaction(isolation)
      begin_db_transaction
      execute "SET TRANSACTION ISOLATION LEVEL #{transaction_isolation_levels.fetch(isolation)}"
    end

commit_db_transaction() click to toggle source

Commits a transaction.

    # File lib/active_record/connection_adapters/postgresql/database_statements.rb, line 221
    def commit_db_transaction
      execute "COMMIT"
    end

create() click to toggle source
Calls superclass method

    # File lib/active_record/connection_adapters/postgresql/database_statements.rb, line 93
    def create
      super.insert
    end

exec_delete(sql, name = 'SQL', binds = []) click to toggle source

    # File lib/active_record/connection_adapters/postgresql/database_statements.rb, line 172
    def exec_delete(sql, name = 'SQL', binds = [])
      execute_and_clear(sql, name, binds) {|result| result.cmd_tuples }
    end

Also aliased as: exec_update
exec_insert(sql, name, binds, pk = nil, sequence_name = nil) click to toggle source

    # File lib/active_record/connection_adapters/postgresql/database_statements.rb, line 191
    def exec_insert(sql, name, binds, pk = nil, sequence_name = nil)
      val = exec_query(sql, name, binds)
      if !use_insert_returning? && pk
        unless sequence_name
          table_ref = extract_table_ref_from_insert_sql(sql)
          sequence_name = default_sequence_name(table_ref, pk)
          return val unless sequence_name
        end
        last_insert_id_result(sequence_name)
      else
        val
      end
    end

exec_query(sql, name = 'SQL', binds = []) click to toggle source

    # File lib/active_record/connection_adapters/postgresql/database_statements.rb, line 159
    def exec_query(sql, name = 'SQL', binds = [])
      execute_and_clear(sql, name, binds) do |result|
        types = {}
        fields = result.fields
        fields.each_with_index do |fname, i|
          ftype = result.ftype i
          fmod  = result.fmod i
          types[fname] = get_oid_type(ftype, fmod, fname)
        end
        ActiveRecord::Result.new(fields, result.values, types)
      end
    end

exec_rollback_db_transaction() click to toggle source

Aborts a transaction.

    # File lib/active_record/connection_adapters/postgresql/database_statements.rb, line 226
    def exec_rollback_db_transaction
      execute "ROLLBACK"
    end

exec_update(sql, name = 'SQL', binds = [])
Alias for: exec_delete
execute(sql, name = nil) click to toggle source

Executes an SQL statement, returning a PGresult object on success or raising a PGError exception otherwise.

    # File lib/active_record/connection_adapters/postgresql/database_statements.rb, line 153
    def execute(sql, name = nil)
      log(sql, name) do
        @connection.async_exec(sql)
      end
    end

explain(arel, binds = []) click to toggle source

    # File lib/active_record/connection_adapters/postgresql/database_statements.rb, line 5
    def explain(arel, binds = [])
      sql = "EXPLAIN #{to_sql(arel, binds)}"
      ExplainPrettyPrinter.new.pp(exec_query(sql, 'EXPLAIN', binds))
    end

insert_sql(sql, name = nil, pk = nil, id_value = nil, sequence_name = nil) click to toggle source

Executes an INSERT query and returns the new record's ID

Calls superclass method

    # File lib/active_record/connection_adapters/postgresql/database_statements.rb, line 76
    def insert_sql(sql, name = nil, pk = nil, id_value = nil, sequence_name = nil)
      unless pk
        # Extract the table from the insert sql. Yuck.
        table_ref = extract_table_ref_from_insert_sql(sql)
        pk = primary_key(table_ref) if table_ref
      end

      if pk && use_insert_returning?
        select_value("#{sql} RETURNING #{quote_column_name(pk)}")
      elsif pk
        super
        last_insert_id_value(sequence_name || default_sequence_name(table_ref, pk))
      else
        super
      end
    end

select_rows(sql, name = nil, binds = []) click to toggle source

Executes a SELECT query and returns an array of rows. Each row is an array of field values.

    # File lib/active_record/connection_adapters/postgresql/database_statements.rb, line 69
    def select_rows(sql, name = nil, binds = [])
      execute_and_clear(sql, name, binds) do |result|
        result.values
      end
    end

select_value(arel, name = nil, binds = []) click to toggle source

    # File lib/active_record/connection_adapters/postgresql/database_statements.rb, line 47
    def select_value(arel, name = nil, binds = [])
      arel, binds = binds_from_relation arel, binds
      sql = to_sql(arel, binds)
      execute_and_clear(sql, name, binds) do |result|
        result.getvalue(0, 0) if result.ntuples > 0 && result.nfields > 0
      end
    end

select_values(arel, name = nil) click to toggle source

    # File lib/active_record/connection_adapters/postgresql/database_statements.rb, line 55
    def select_values(arel, name = nil)
      arel, binds = binds_from_relation arel, []
      sql = to_sql(arel, binds)
      execute_and_clear(sql, name, binds) do |result|
        if result.nfields > 0
          result.column_values(0)
        else
          []
        end
      end
    end

sql_for_insert(sql, pk, id_value, sequence_name, binds) click to toggle source

    # File lib/active_record/connection_adapters/postgresql/database_statements.rb, line 177
    def sql_for_insert(sql, pk, id_value, sequence_name, binds)
      unless pk
        # Extract the table from the insert sql. Yuck.
        table_ref = extract_table_ref_from_insert_sql(sql)
        pk = primary_key(table_ref) if table_ref
      end

      if pk && use_insert_returning?
        sql = "#{sql} RETURNING #{quote_column_name(pk)}"
      end

      [sql, binds]
    end

update_sql(sql, name = nil) click to toggle source

Executes an UPDATE query and returns the number of affected tuples.

Calls superclass method

    # File lib/active_record/connection_adapters/postgresql/database_statements.rb, line 206
    def update_sql(sql, name = nil)
      super.cmd_tuples
    end