Class: DataMapper::Adapters::DataObjectAdapter

Inherits:
AbstractAdapter show all
Includes:
Coersion, Sql, Quoting
Defined in:
lib/data_mapper/adapters/data_object_adapter.rb

Overview

You must inherit from the DoAdapter, and implement the required methods to adapt a database library for use with the DataMapper.

NOTE: By inheriting from DoAdapter, you get a copy of all the standard sub-modules (Quoting, Coersion and Queries) in your own Adapter. You can extend and overwrite these copies without affecting the originals.

Direct Known Subclasses

MysqlAdapter, PostgresqlAdapter, Sqlite3Adapter

Constant Summary collapse

FIND_OPTIONS = 
[
  :select, :offset, :limit, :class, :include, :shallow_include, :reload, :conditions, :order, :intercept_load
]
TABLE_QUOTING_CHARACTER = 
'`'.freeze
COLUMN_QUOTING_CHARACTER = 
'`'.freeze
SYNTAX = 
{
  :now => 'NOW()'.freeze
}
MAGIC_PROPERTIES = 
{
  :updated_at => lambda { self.updated_at = Time::now },
  :updated_on => lambda { self.updated_on = Date::today },
  :created_at => lambda { self.created_at ||= Time::now },
  :created_on => lambda { self.created_on ||= Date::today }
}
TYPES = 
{
  :integer => 'int'.freeze,
  :string => 'varchar'.freeze,
  :text => 'text'.freeze,
  :class => 'varchar'.freeze,
  :decimal => 'decimal'.freeze,
  :float => 'float'.freeze,
  :datetime => 'datetime'.freeze,
  :date => 'date'.freeze,
  :boolean => 'boolean'.freeze,
  :object => 'text'.freeze
}

Class Method Summary collapse

Instance Method Summary collapse

Methods inherited from AbstractAdapter

#index_path, #logger, #name

Constructor Details

#initialize(configuration) ⇒ DataObjectAdapter

Returns a new instance of DataObjectAdapter.



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# File 'lib/data_mapper/adapters/data_object_adapter.rb', line 55

def initialize(configuration)
  super
  @connection_pool = Support::ConnectionPool.new { create_connection }
end

Class Method Details

.inherited(base) ⇒ Object

This callback copies and sub-classes modules and classes in the DoAdapter to the inherited class so you don’t have to copy and paste large blocks of code from the DoAdapter.

Basically, when inheriting from the DoAdapter, you aren’t just inheriting a single class, you’re inheriting a whole graph of Types. For convenience.



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# File 'lib/data_mapper/adapters/data_object_adapter.rb', line 439

def self.inherited(base)

  commands = base.const_set('Commands', Module.new)

  Sql::Commands.constants.each do |name|
    commands.const_set(name, Class.new(Sql::Commands.const_get(name)))
  end

  mappings = base.const_set('Mappings', Module.new)

  Sql::Mappings.constants.each do |name|
    mappings.const_set(name, Class.new(Sql::Mappings.const_get(name)))
  end

  base.const_set('TYPES', TYPES.dup)
  base.const_set('FIND_OPTIONS', FIND_OPTIONS.dup)
  base.const_set('SYNTAX', SYNTAX.dup)

  super
end

Instance Method Details

#activate! ⇒ Object 



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# File 'lib/data_mapper/adapters/data_object_adapter.rb', line 64

def activate!
  @activated = true
  schema.activate!
end

#activated? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/data_mapper/adapters/data_object_adapter.rb', line 60

def activated?
  @activated
end

#batch_insertable? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/data_mapper/adapters/data_object_adapter.rb', line 73

def batch_insertable?
  true
end

#callback(instance, callback_name) ⇒ Object 



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# File 'lib/data_mapper/adapters/data_object_adapter.rb', line 427

def callback(instance, callback_name)
  instance.class.callbacks.execute(callback_name, instance)
end

#column_exists_for_table?(table_name, column_name) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/data_mapper/adapters/data_object_adapter.rb', line 166

def column_exists_for_table?(table_name, column_name)
  connection do |db|
    table = self.table(table_name)
    command = db.create_command(table.to_column_exists_sql)
    command.execute_reader(table.name, column_name, table.schema.name) do |reader|
      reader.any? { reader.item(1) == column_name.to_s }
    end
  end
end

#connection ⇒ Object

Yields an available connection. Flushes the connection-pool and reconnects if the connection returns an error.



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# File 'lib/data_mapper/adapters/data_object_adapter.rb', line 79

def connection
  begin
    # Yield the appropriate connection
    @connection_pool.hold { |active_connection| yield(active_connection) }
  rescue => execution_error
    # Log error on failure
    logger.error { execution_error }

    # Close all open connections, assuming that if one
    # had an error, it's likely due to a lost connection,
    # in which case all connections are likely broken.
    flush_connections!

    raise execution_error
  end
end

#create(database_context, instance) ⇒ Object 



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# File 'lib/data_mapper/adapters/data_object_adapter.rb', line 285

def create(database_context, instance)
  callback(instance, :before_create)

  instance = update_magic_properties(database_context, instance)

  table = self.table(instance)
  attributes = instance.dirty_attributes

  if table.multi_class?
    instance.instance_variable_set(
      table[:type].instance_variable_name,
      attributes[:type] = instance.class.name
    )
  end

  keys = []
  values = []
  attributes.each_pair do |key, value|
    raise ArgumentError.new("#{value.inspect} is not a valid value for #{key.inspect}") if value.is_a?(Array)

    keys << table[key].to_sql
    values << value
  end

  sql = if keys.size > 0
    "INSERT INTO #{table.to_sql} (#{keys.join(', ')}) VALUES ?"
  else
    "INSERT INTO #{table.to_sql} #{self.empty_insert_sql}"
  end

  result = connection do |db|
    db.create_command(sql).execute_non_query(values)
  end

  if result.to_i > 0
    instance.instance_variable_set(:@new_record, false)
    instance.key = result.last_insert_row if table.key.serial? && !attributes.include?(table.key.name)
    database_context.identity_map.set(instance)
    callback(instance, :after_create)
    return true
  else
    return false
  end
end

#create_connection ⇒ Object

Raises:

  • (NotImplementedError) 


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# File 'lib/data_mapper/adapters/data_object_adapter.rb', line 69

def create_connection
  raise NotImplementedError.new
end

#delete(database_context, instance) ⇒ Object 



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# File 'lib/data_mapper/adapters/data_object_adapter.rb', line 176

def delete(database_context, instance)
  table = self.table(instance)

  if instance.is_a?(Class)
    table.delete_all!
  else
    callback(instance, :before_destroy)

    table.associations.each do |association|
      instance.send(association.name).deactivate unless association.is_a?(::DataMapper::Associations::BelongsToAssociation)
    end

    if table.paranoid?
      instance.instance_variable_set(table.paranoid_column.instance_variable_name, Time::now)
      instance.save
    else
      if connection do |db|
          command = db.create_command("DELETE FROM #{table.to_sql} WHERE #{table.key.to_sql} = ?")
          command.execute_non_query(instance.key).to_i > 0
        end # connection do...end # if continued below:
        instance.instance_variable_set(:@new_record, true)
        instance.database_context = database_context
        instance.original_values.clear
        database_context.identity_map.delete(instance)
        callback(instance, :after_destroy)
      end
    end
  end
end

#empty_insert_sql ⇒ Object 



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# File 'lib/data_mapper/adapters/data_object_adapter.rb', line 281

def empty_insert_sql
  "DEFAULT VALUES"
end

#execute(*args) ⇒ Object 



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# File 'lib/data_mapper/adapters/data_object_adapter.rb', line 147

def execute(*args)
  db = create_connection
  command = db.create_command(args.shift)
  return command.execute_non_query(*args)
rescue => e
  logger.error { e }
  raise e
ensure
  db.close
end

#flush_connections! ⇒ Object

Close any open connections.



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# File 'lib/data_mapper/adapters/data_object_adapter.rb', line 97

def flush_connections!          
  @connection_pool.available_connections.each do |active_connection|
    begin
      active_connection.close
    rescue => close_connection_error
      # An error on closing the connection is almost expected
      # if the socket is broken.
      logger.warn { close_connection_error }
    end
  end

  # Reopen fresh connections.
  @connection_pool.instance_variable_set('@created_count', 0)
  @connection_pool.available_connections.clear
end

#get(database_context, klass, keys) ⇒ Object 



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# File 'lib/data_mapper/adapters/data_object_adapter.rb', line 348

def get(database_context, klass, keys)
  table = self.table(klass)
  instance_id = table.key.type_cast_value(keys.first)
  instance = database_context.identity_map.get(klass, instance_id)

  return instance if instance

  column_indexes = {}
  select_columns = []

  table.columns.each_with_index do |column, i|
    column_indexes[column] = i
    select_columns << column.to_sql
  end

  sql = "SELECT #{select_columns.join(', ')} FROM #{table.to_sql} WHERE #{table.keys.map { |key| "#{key.to_sql} = ?" }.join(' AND ')}"

  connection do |db|
    reader = nil
    begin
      reader = db.create_command(sql).execute_reader(*keys)

      if reader.has_rows?

        instance_type = klass

        if table.multi_class? && table.type_column
          value = reader.item(column_indexes[table.type_column])
          instance_type = table.type_column.type_cast_value(value) unless value.blank?
        end

        if instance.nil?
          instance = instance_type.allocate()
          instance.instance_variable_set(:@__key, instance_id)
          instance.instance_variable_set(:@new_record, false)
          database_context.identity_map.set(instance)
        elsif instance.new_record?
          instance.instance_variable_set(:@__key, instance_id)
          instance.instance_variable_set(:@new_record, false)
          database_context.identity_map.set(instance)
        end

        instance.database_context = database_context

        instance_type.callbacks.execute(:before_materialize, instance)

        originals = instance.original_values

        column_indexes.each_pair do |column, i|
          value = column.type_cast_value(reader.item(i))
          instance.instance_variable_set(column.instance_variable_name, value)

          case value
            when String, Date, Time then originals[column.name] = value.dup
            else originals[column.name] = value
          end
        end

        instance.loaded_set = [instance]

        instance_type.callbacks.execute(:after_materialize, instance)
      end # if reader.has_rows?
    ensure
      reader.close if reader && reader.open?
    end
  end # connection

  return instance
end

#handle_error(error) ⇒ Object 



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# File 'lib/data_mapper/adapters/data_object_adapter.rb', line 158

def handle_error(error)
  raise error
end

#load(database_context, klass, options) ⇒ Object 



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# File 'lib/data_mapper/adapters/data_object_adapter.rb', line 344

def load(database_context, klass, options)
  self.class::Commands::LoadCommand.new(self, database_context, klass, options).call
end

#query(*args) ⇒ Object 



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# File 'lib/data_mapper/adapters/data_object_adapter.rb', line 117

def query(*args)
  db = create_connection

  command = db.create_command(args.shift)

  reader = command.execute_reader(*args)
  fields = reader.fields.map { |field| Inflector.underscore(field).to_sym }
  results = []

  if fields.size > 1
    struct = Struct.new(*fields)

    reader.each do
      results << struct.new(*reader.current_row)
    end
  else
    reader.each do
      results << reader.item(0)
    end
  end

  return results
rescue => e
  logger.error { e }
  raise e
ensure
  reader.close if reader
  db.close
end

#save(database_context, instance, validate = true, cleared = Set.new) ⇒ Object 



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# File 'lib/data_mapper/adapters/data_object_adapter.rb', line 206

def save(database_context, instance, validate = true, cleared = Set.new)
  case instance
  when Class then
    table(instance).create!
    table(instance).activate_associations!
  when Mappings::Table then instance.create!
  when DataMapper::Persistence then
    event = instance.new_record? ? :create : :update

    return false if (validate && !instance.validate_recursively(event, Set.new)) || cleared.include?(instance)
    cleared << instance

    callback(instance, :before_save)

    return true unless instance.new_record? || instance.dirty?

    result = send(event, database_context, instance)

    instance.database_context = database_context
    instance.attributes.each_pair do |name, value|
      instance.original_values[name] = value
    end

    instance.loaded_associations.each do |association|
      association.save_without_validation(database_context, cleared) if association.dirty?
    end

    callback(instance, :after_save)
    result
  end
rescue => error
  logger.error(error)
  raise error
end

#save_without_validation(database_context, instance, cleared = Set.new) ⇒ Object 



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# File 'lib/data_mapper/adapters/data_object_adapter.rb', line 241

def save_without_validation(database_context, instance, cleared = Set.new)
  save(database_context, instance, false, cleared)
end

#schema ⇒ Object 



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# File 'lib/data_mapper/adapters/data_object_adapter.rb', line 162

def schema
  @schema || ( @schema = self.class::Mappings::Schema.new(self, @configuration.database) )
end

#table(instance) ⇒ Object 



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# File 'lib/data_mapper/adapters/data_object_adapter.rb', line 418

def table(instance)
  case instance
  when DataMapper::Adapters::Sql::Mappings::Table then instance
  when DataMapper::Persistence then schema[instance.class]
  when Class, String then schema[instance]
  else raise "Don't know how to map #{instance.inspect} to a table."
  end
end

#transaction(&block) ⇒ Object

Raises:

  • (NotImplementedError) 


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# File 'lib/data_mapper/adapters/data_object_adapter.rb', line 113

def transaction(&block)
  raise NotImplementedError.new
end

#update(database_context, instance) ⇒ Object 



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# File 'lib/data_mapper/adapters/data_object_adapter.rb', line 245

def update(database_context, instance)
  callback(instance, :before_update)

  instance = update_magic_properties(database_context, instance)

  table = self.table(instance)
  attributes = instance.dirty_attributes
  parameters = []

  unless attributes.empty?
    sql = "UPDATE " << table.to_sql << " SET "

    sql << attributes.map do |key, value|
      parameters << value
      "#{table[key].to_sql} = ?"
    end.join(', ')

    sql << " WHERE #{table.key.to_sql} = ?"
    parameters << instance.key

    result = connection do |db|
      db.create_command(sql).execute_non_query(*parameters)
    end

    # BUG: do_mysql returns inaccurate affected row counts for UPDATE statements.
    if true || result.to_i > 0
      callback(instance, :after_update)
      return true
    else
      return false
    end
  else
    true
  end
end

#update_magic_properties(database_context, instance) ⇒ Object 



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# File 'lib/data_mapper/adapters/data_object_adapter.rb', line 337

def update_magic_properties(database_context, instance)
  instance.class.properties.find_all { |property| MAGIC_PROPERTIES.has_key?(property.name) }.each do |property|
    instance.instance_eval(&MAGIC_PROPERTIES[property.name])
  end
  instance
end