PLC/Storage/AlchemyObject.py

   1 from datetime import datetime
   2
   3 from sqlalchemy.ext.declarative import declarative_base
   4 from sqlalchemy import Table, Column, MetaData, join, ForeignKey
   5 from sqlalchemy import Column, Integer, String, TIMESTAMP
   6 from sqlalchemy.orm import relationship, backref
   7 from sqlalchemy.orm import column_property
   8 from sqlalchemy.orm import mapper, object_mapper
   9 from sqlalchemy.orm import validates
  10 from sqlalchemy import ForeignKey
  11
  12 from PLC.Storage.Alchemy import Base, engine, dbsession
  13 from PLC.Storage.Record import Record
  14 from PLC.Timestamp import Timestamp
  15 from PLC.Logger import logger
  16
  17 class AlchemyObj(Record):
  18
  19     def __init__(self, api=None, fields = {}, object=None):
  20         Record.__init__(self, dict=fields, object=object)
  21         self.api=api
  22
  23     def __iter__(self):
  24         self._i = iter(object_mapper(self).columns)
  25         return self
  26
  27     def next(self):
  28         n = self._i.next().name
  29         return n, getattr(self, n)
  30
  31     def get_table(self):
  32         metadata = MetaData(engine)
  33         table = Table(self.tablename, metadata)
  34         for field in self.fields:
  35             param = self.fields[field]
  36             args = {}
  37             # skip params joined from other tables
  38             if param.joined:
  39                 continue
  40             type = String
  41             if param.type == int:
  42                 type = Integer
  43             elif param.type == datetime:
  44                 type = TIMESTAMP
  45
  46             column = Column(field, type,
  47                             nullable = param.nullok,
  48                             index = param.indexed,
  49                             primary_key=param.primary_key,
  50                             default=param.default)
  51             table.append_column(column)
  52         if not table.exists():
  53             table.create()
  54         return table
  55
  56     def create(self):
  57         self.get_table()
  58
  59     def insert(self, values):
  60         table = self.get_table()
  61         result = dbsession.execute(table.insert().values(values))
  62         dbsession.commit()
  63         return result
  64
  65     def updatedb(self, filter, values):
  66         class Cls(object): pass
  67         table = self.get_table()
  68         clsmapper = mapper(Cls, table)
  69         result = dbsession.query(clsmapper).filter_by(**filter).update(values)
  70         dbsession.commit()
  71         return result
  72
  73     def delete(self, filter={}):
  74         class Cls(object): pass
  75         table = self.get_table()
  76         clsmapper = mapper(Cls, table)
  77         result = dbsession.query(clsmapper).filter_by(**filter).delete()
  78         dbsession.commit()
  79         return result
  80
  81     def select(self, filter={}):
  82         class Cls(object): pass
  83         table = self.get_table()
  84         clsmapper = mapper(Cls, table)
  85         return dbsession.query(clsmapper).filter_by(**filter)