Module: Sequel::Plugins::ClassTableInheritance::ClassMethods

Defined in:
lib/sequel/lib/sequel/plugins/class_table_inheritance.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Instance Attribute Details

#cti_base_modelObject (readonly)

The parent/root/base model for this class table inheritance hierarchy. This is the only model in the hierarchy that load the class_table_inheritance plugin.


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# File 'lib/sequel/lib/sequel/plugins/class_table_inheritance.rb', line 94

def cti_base_model
  @cti_base_model
end

#cti_columnsObject (readonly)

Hash with table name symbol keys and arrays of column symbol values, giving the columns to update in each backing database table.


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# File 'lib/sequel/lib/sequel/plugins/class_table_inheritance.rb', line 98

def cti_columns
  @cti_columns
end

#cti_keyObject (readonly)

The column containing the class name as a string. Used to return instances of subclasses when calling the superclass's load method.


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# File 'lib/sequel/lib/sequel/plugins/class_table_inheritance.rb', line 103

def cti_key
  @cti_key
end

#cti_table_mapObject (readonly)

A hash with class name symbol keys and table name symbol values. Specified with the :table_map option to the plugin, and used if the implicit naming is incorrect.


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# File 'lib/sequel/lib/sequel/plugins/class_table_inheritance.rb', line 113

def cti_table_map
  @cti_table_map
end

#cti_tablesObject (readonly)

An array of table symbols that back this model. The first is cti_base_model table symbol, and the last is the current model table symbol.


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# File 'lib/sequel/lib/sequel/plugins/class_table_inheritance.rb', line 108

def cti_tables
  @cti_tables
end

Instance Method Details

#inherited(subclass) ⇒ Object

Add the appropriate data structures to the subclass. Does not allow anonymous subclasses to be created, since they would not be mappable to a table.


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# File 'lib/sequel/lib/sequel/plugins/class_table_inheritance.rb', line 118

def inherited(subclass)
  cc = cti_columns
  ck = cti_key
  ct = cti_tables.dup
  ctm = cti_table_map.dup
  cbm = cti_base_model
  pk = primary_key
  ds = dataset
  subclass.instance_eval do
    raise(Error, "cannot create anonymous subclass for model class using class_table_inheritance") if !(n = name) || n.empty?
    table = ctm[n.to_sym] || implicit_table_name
    columns = db.from(table).columns
    @cti_key = ck 
    @cti_tables = ct + [table]
    @cti_columns = cc.merge(table=>columns)
    @cti_table_map = ctm
    @cti_base_model = cbm
    # Need to set dataset and columns before calling super so that
    # the main column accessor module is included in the class before any
    # plugin accessor modules (such as the lazy attributes accessor module).
    set_dataset(ds.join(table, [pk]))
    set_columns(self.columns)
  end
  super
  subclass.instance_eval do
    m = method(:constantize)
    dataset.row_proc = lambda{|r| (m.call(r[ck]) rescue subclass).load(r)}
    (columns - [cbm.primary_key]).each{|a| define_lazy_attribute_getter(a)}
    cti_tables.reverse.each do |table|
      db.schema(table).each{|k,v| db_schema[k] = v}
    end
  end
end

#primary_keyObject

The primary key in the parent/base/root model, which should have a foreign key with the same name referencing it in each model subclass.


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# File 'lib/sequel/lib/sequel/plugins/class_table_inheritance.rb', line 154

def primary_key
  return super if self == cti_base_model
  cti_base_model.primary_key
end

#table_nameObject

The table name for the current model class's main table (not used by any superclasses).


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# File 'lib/sequel/lib/sequel/plugins/class_table_inheritance.rb', line 161

def table_name
  self == cti_base_model ? super : cti_tables.last
end