Module: ActiveRecord::ConnectionAdapters::DatabaseStatements

# File activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb, line 97
      def add_limit!(sql, options)
        add_limit_offset!(sql, options) if options
      end

add_limit_offset!(sql, options)

Appends LIMIT and OFFSET options to a SQL statement. This method modifies the sql parameter.

Examples

 add_limit_offset!('SELECT * FROM suppliers', {:limit => 10, :offset => 50})

generates

 SELECT * FROM suppliers LIMIT 10 OFFSET 50

[Source]

# File activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb, line 107
      def add_limit_offset!(sql, options)
        if limit = options[:limit]
          sql << " LIMIT #{limit}"
          if offset = options[:offset]
            sql << " OFFSET #{offset}"
          end
        end
      end

add_lock!(sql, options)

Appends a locking clause to a SQL statement. *Modifies the sql parameter*.

  # SELECT * FROM suppliers FOR UPDATE
  add_lock! 'SELECT * FROM suppliers', :lock => true
  add_lock! 'SELECT * FROM suppliers', :lock => ' FOR UPDATE'

[Source]

# File activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb, line 120
      def add_lock!(sql, options)
        case lock = options[:lock]
          when true;   sql << ' FOR UPDATE'
          when String; sql << " #{lock}"
        end
      end

begin_db_transaction()

Begins the transaction (and turns off auto-committing).

[Source]

# File activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb, line 87
      def begin_db_transaction()    end

commit_db_transaction()

Commits the transaction (and turns on auto-committing).

[Source]

# File activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb, line 90
      def commit_db_transaction()   end

default_sequence_name(table, column)

[Source]

# File activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb, line 127
      def default_sequence_name(table, column)
        nil
      end

delete(sql, name = nil)

Executes the delete statement and returns the number of rows affected.

[Source]

# File activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb, line 53
      def delete(sql, name = nil)
        delete_sql(sql, name)
      end

execute(sql, name = nil)

Executes the SQL statement in the context of this connection.

[Source]

# File activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb, line 38
      def execute(sql, name = nil)
        raise NotImplementedError, "execute is an abstract method"
      end

insert(sql, name = nil, pk = nil, id_value = nil, sequence_name = nil)

Returns the last auto-generated ID from the affected table.

[Source]

# File activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb, line 43
      def insert(sql, name = nil, pk = nil, id_value = nil, sequence_name = nil)
        insert_sql(sql, name, pk, id_value, sequence_name)
      end

insert_fixture(fixture, table_name)

Inserts the given fixture into the table. Overridden in adapters that require something beyond a simple insert (eg. Oracle).

[Source]

# File activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb, line 138
      def insert_fixture(fixture, table_name)
        execute "INSERT INTO #{table_name} (#{fixture.key_list}) VALUES (#{fixture.value_list})", 'Fixture Insert'
      end

reset_sequence!(table, column, sequence = nil)

Set the sequence to the max value of the table’s column.

[Source]

# File activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb, line 132
      def reset_sequence!(table, column, sequence = nil)
        # Do nothing by default.  Implement for PostgreSQL, Oracle, ...
      end

rollback_db_transaction()

Rolls back the transaction (and turns on auto-committing). Must be done if the transaction block raises an exception or returns false.

[Source]

# File activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb, line 94
      def rollback_db_transaction() end

select_all(sql, name = nil)

Returns an array of record hashes with the column names as keys and column values as values.

[Source]

# File activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb, line 6
      def select_all(sql, name = nil)
        select(sql, name)
      end

select_one(sql, name = nil)

Returns a record hash with the column names as keys and column values as values.

[Source]

# File activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb, line 12
      def select_one(sql, name = nil)
        result = select_all(sql, name)
        result.first if result
      end

select_rows(sql, name = nil)

Returns an array of arrays containing the field values. Order is the same as that returned by columns.

[Source]

# File activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb, line 33
      def select_rows(sql, name = nil)
        raise NotImplementedError, "select_rows is an abstract method"
      end

select_value(sql, name = nil)

Returns a single value from a record

[Source]

# File activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb, line 18
      def select_value(sql, name = nil)
        if result = select_one(sql, name)
          result.values.first
        end
      end

select_values(sql, name = nil)

Returns an array of the values of the first column in a select:

  select_values("SELECT id FROM companies LIMIT 3") => [1,2,3]

[Source]

# File activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb, line 26
      def select_values(sql, name = nil)
        result = select_rows(sql, name)
        result.map { |v| v[0] }
      end

transaction(start_db_transaction = true) {|| ...}

Wrap a block in a transaction. Returns result of block.

[Source]

# File activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb, line 58
      def transaction(start_db_transaction = true)
        transaction_open = false
        begin
          if block_given?
            if start_db_transaction
              begin_db_transaction
              transaction_open = true
            end
            yield
          end
        rescue Exception => database_transaction_rollback
          if transaction_open
            transaction_open = false
            rollback_db_transaction
          end
          raise unless database_transaction_rollback.is_a? ActiveRecord::Rollback
        end
      ensure
        if transaction_open
          begin
            commit_db_transaction
          rescue Exception => database_transaction_rollback
            rollback_db_transaction
            raise
          end
        end
      end

update(sql, name = nil)

Executes the update statement and returns the number of rows affected.

[Source]

# File activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb, line 48
      def update(sql, name = nil)
        update_sql(sql, name)
      end

delete_sql(sql, name = nil)

Executes the delete statement and returns the number of rows affected.

[Source]

# File activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb, line 161
        def delete_sql(sql, name = nil)
          update_sql(sql, name)
        end

insert_sql(sql, name = nil, pk = nil, id_value = nil, sequence_name = nil)

Returns the last auto-generated ID from the affected table.

[Source]

# File activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb, line 150
        def insert_sql(sql, name = nil, pk = nil, id_value = nil, sequence_name = nil)
          execute(sql, name)
          id_value
        end

select(sql, name = nil)

Returns an array of record hashes with the column names as keys and column values as values.

[Source]

# File activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb, line 145
        def select(sql, name = nil)
          raise NotImplementedError, "select is an abstract method"
        end

update_sql(sql, name = nil)

Executes the update statement and returns the number of rows affected.

[Source]

# File activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb, line 156
        def update_sql(sql, name = nil)
          execute(sql, name)
        end

Methods

Public Instance methods

Examples

Protected Instance methods