Module: Flounder::PostgresUtils

Included in:
Connection, Result::Descriptor
Defined in:
lib/flounder/postgres_utils.rb

Constant Summary collapse

OID_BOOLEAN = 
16
OID_SMALLINT = 
21
OID_INTEGER = 
23
OID_TEXT = 
25
OID_FLOAT = 
701
OID_VARCHAR = 
1043
OID_TIMESTAMP = 
1114
OID_DATE = 
1082
OID_TIME = 
1083
OID_TIMESTAMPTZ = 
1184

Instance Method Summary collapse

Instance Method Details

#access_value(connection, result, type_oid, row_idx, col_idx) ⇒ Object 



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# File 'lib/flounder/postgres_utils.rb', line 116

def access_value connection, result, type_oid, row_idx, col_idx
  value = result.getvalue(row_idx, col_idx)
  typecast(connection, type_oid, value)
end

#each_field(entity, result) {|idx, entity, field_name, type, binary| ... } ⇒ Object

Yields header information for each column in the given result in turn.

Yield Parameters:

  • idx (Integer) —

    column index

  • entity (Flounder::Entity) —

    entity as resolved by table OID

  • field_name (String) —

    field name as present in the SQL result

  • type (Integer) —

    type OID

  • binary (Boolean) —

    is this a binary field?



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# File 'lib/flounder/postgres_utils.rb', line 100

def each_field entity, result
  domain = entity.domain

  result.nfields.times do |field_idx|
    table_oid = result.ftable(field_idx)
    entity = domain.by_oid(table_oid)

    yield(
      field_idx, 
      entity,
      result.fname(field_idx),
      result.ftype(field_idx), 
      result.fformat(field_idx) == 1)
  end
end

#oid_hstore(connection) ⇒ Object 



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# File 'lib/flounder/postgres_utils.rb', line 52

def oid_hstore connection
  unless @oid_hstore_initialized
    @oid_hstore_initialized = true

    @oid_hstore = begin 
      result = connection.exec("SELECT oid FROM pg_type WHERE typname='hstore'")
      row = result.first

      row && row.values.first.to_i
    end
  end

  @oid_hstore
end

#type_name(ftype, fmod) ⇒ Object

Helper function for debugging



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# File 'lib/flounder/postgres_utils.rb', line 122

def type_name ftype, fmod
  pg.
    exec( "SELECT format_type($1,$2)", 
      [ftype, fmod] ).
    getvalue( 0, 0 )
end

#type_oid_to_sym(connection, oid) ⇒ Object

Raises:

  • (ArgumentError) 


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# File 'lib/flounder/postgres_utils.rb', line 67

def type_oid_to_sym connection, oid
  raise ArgumentError, "AF: oid must not be nil" unless oid

  return :hash if oid==oid_hstore(connection)

  case oid
    when OID_TIMESTAMP, OID_TIMESTAMPTZ
      :datetime
    when OID_DATE
      :date
    when OID_TIME
      :time
    when OID_INTEGER, OID_SMALLINT
      :integer
    when OID_FLOAT
      :float
    when OID_VARCHAR, OID_TEXT
      :string
    when OID_BOOLEAN
      :boolean
  else
    nil
  end
end

#typecast(connection, type_oid, value) ⇒ Object

Raises:

  • (ArgumentError) 


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# File 'lib/flounder/postgres_utils.rb', line 19

def typecast connection, type_oid, value
  raise ArgumentError, "AF: type_oid must not be nil" unless type_oid

  return nil unless value

  # hstore extension
  if type_oid == oid_hstore(connection)
    return PgHstore.load(value) 
  end

  # assert: value is not nil
  case type_oid
    when OID_TIMESTAMPTZ
      DateTime.parse(value)
    when OID_TIMESTAMP
      DateTime.parse(value)
    when OID_DATE
      Date.parse(value)
    when OID_TIME
      Time.parse(value)
    when OID_INTEGER, OID_SMALLINT
      value.to_i
    when OID_FLOAT
      value.to_f
    when OID_BOOLEAN
      value == 't'
    when OID_TEXT
      value.to_s      
  else
    value
  end
end