Module: DataMapper::Reflection::PostgresAdapter

Defined in:
lib/dm-reflection/adapters/postgres.rb

Instance Method Summary collapse

Instance Method Details

#get_primary_keys(table) ⇒ Array<String>

Returna list of columns in the primary key

Parameters:

  • the (String) —

    table name

Returns:

  • (Array<String>) —

    the names of the columns in the primary key



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# File 'lib/dm-reflection/adapters/postgres.rb', line 55

def get_primary_keys(table)
  select("        SELECT \"key_column_usage\".\"column_name\"\n          FROM \"information_schema\".\"table_constraints\"\n    INNER JOIN \"information_schema\".\"key_column_usage\" USING(\"constraint_schema\", \"constraint_name\")\n         WHERE \"table_constraints\".\"constraint_type\" = 'PRIMARY KEY'\n           AND \"table_constraints\".\"table_name\" = ?\n  SQL\nend\n".compress_lines, table).to_set

#get_properties(table) ⇒ Hash

TODO:

Consider returning actual DataMapper::Properties from this. It would probably require passing in a Model Object.

Get the column specifications for a specific table

Parameters:

  • table (String) —

    the name of the table to get column specifications for

Returns:

  • (Hash) —

    the column specs are returned in a hash keyed by :name, :field, :type, :required, :default, :key



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# File 'lib/dm-reflection/adapters/postgres.rb', line 74

def get_properties(table)
  columns = select("      SELECT \"column_name\"\n           , \"data_type\"\n           , \"column_default\"\n           , \"is_nullable\"\n           , \"character_maximum_length\"\n           , \"numeric_precision\"\n        FROM \"information_schema\".\"columns\"\n       WHERE \"table_schema\" = ?\n         AND \"table_name\" = ?\n    ORDER BY \"ordinal_position\"\n  SQL\n\n  primary_keys = get_primary_keys(table)\n\n  columns.map do |column|\n    type     = get_type(column.data_type)\n    default  = column.column_default\n    required = column.is_nullable == 'NO'\n    key      = primary_keys.include?(column.column_name)\n    length   = column.character_maximum_length\n\n    if type == Integer && default\n      if key\n        type    = DataMapper::Types::Serial if default[/\\Anextval/]\n        default = nil\n      else\n        default = default.to_i\n      end\n    end\n\n    if length\n      length = (required ? 1 : 0)..length\n    end\n    \n    field_name = column.column_name.downcase\n\n    attribute = {\n      :name     => field_name,\n      :type     => type,\n      :required => required,\n      :default  => default,\n      :key      => key,\n      :length   => length,\n    }\n\n    if type == Integer && field_name[-3,3] == \"_id\"\n      # This is a foriegn key. So this model belongs_to the other (_id) one.\n      # Add a special set of values and flag this as a relationship so the reflection code\n      # can rebuild the relationship when it's building the model.\n      attribute[:type] = DataMapper::Associations::Relationship\n      attribute[:relationship] = { \n        :parent => ActiveSupport::Inflector.classify(field_name[0..-4]), \n        :child => ActiveSupport::Inflector.classify(table), \n        # When we can detect more from the database we can optimize this\n        :cardinality => Infinity, \n        :bidirectional => true }\n    end\n\n    # TODO: use the naming convention to compare the name vs the column name\n    unless attribute[:name] == column.column_name\n      attribute[:field] = column.column_name\n    end\n\n    attribute\n  end\nend\n".compress_lines, schema_name, table)

#get_storage_names ⇒ String Array

Get the list of table names

Returns:

  • (String Array) —

    the names of the tables in the database.



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# File 'lib/dm-reflection/adapters/postgres.rb', line 41

def get_storage_names
  select("    SELECT \"relname\"\n      FROM \"pg_stat_user_tables\"\n     WHERE \"schemaname\" = 'public'\n  SQL\nend\n".compress_lines)

#get_type(db_type) ⇒ Type

TODO:

This should be verified to identify all mysql primitive types and that they map to the correct DataMapper/Ruby types.

Convert the database type into a DataMapper type

Parameters:

  • db_type (String) —

    type specified by the database

Returns:

  • (Type) —

    a DataMapper or Ruby type object.



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# File 'lib/dm-reflection/adapters/postgres.rb', line 17

def get_type(db_type)
  {
    'integer'                     =>  Integer        ,
    'varchar'                     =>  String         ,
    'character varying'           =>  String         ,
    'numeric'                     =>  BigDecimal     ,
    'double precision'            =>  Float          ,
    'datetime'                    =>  DateTime       ,
    'date'                        =>  Date           ,
    'boolean'                     =>  Types::Boolean ,
    'text'                        =>  Types::Text    ,
    'timestamp without time zone' =>  DateTime       ,
  }[db_type] || raise("unknown db type: #{db_type}")
end

#separator ⇒ Object 



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# File 'lib/dm-reflection/adapters/postgres.rb', line 32

def separator
  '--'
end