1# This program is free software; you can redistribute it and/or modify
2# it under the terms of the GNU General Public License as published by
3# the Free Software Foundation; either version 2 of the License, or
4# (at your option) any later version.
6# This program is distributed in the hope that it will be useful,
7# but WITHOUT ANY WARRANTY; without even the implied warranty of
8# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
9# GNU General Public License for more details.
11# You should have received a copy of the GNU General Public License
12# along with this program; if not, write to the Free Software
13# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
15################################################################################
17from sqlalchemy import Column, DateTime
18from sqlalchemy.event import listen
19from sqlalchemy.ext.declarative import declarative_base
20from sqlalchemy.schema import DDL, Table
21from sqlalchemy.sql import func
24Base = declarative_base()
27class BaseMethods(Base):
28 __abstract__ = True
30 @classmethod
31 def get(cls, primary_key, session):
32 '''
33 This is a support function that allows getting an object by its primary
34 key.
36 Architecture.get(3[, session])
38 instead of the more verbose
40 session.query(Architecture).get(3)
41 '''
42 return session.query(cls).get(primary_key)
45class BaseTimestamp(BaseMethods):
46 __abstract__ = True
48 created = Column(DateTime(timezone=True), nullable=False, server_default=func.now())
49 modified = Column(DateTime(timezone=True), nullable=False, server_default=func.now())
51 modified_trigger_function = DDL("""
52CREATE OR REPLACE FUNCTION tfunc_set_modified() RETURNS trigger
53LANGUAGE plpgsql
54AS $$
55 BEGIN NEW.modified = now(); return NEW; END;
56$$
57 """)
59 modified_trigger = DDL("""
60CREATE TRIGGER %(table)s_modified BEFORE UPDATE ON %(fullname)s
61FOR EACH ROW EXECUTE PROCEDURE tfunc_set_modified()
62 """)
64 @classmethod
65 def __table_cls__(cls, *arg, **kw):
66 table = Table(*arg, **kw)
67 listen(
68 table,
69 'after_create',
70 cls.modified_trigger_function.execute_if(dialect='postgresql'),
71 )
72 listen(
73 table,
74 'after_create',
75 cls.modified_trigger.execute_if(dialect='postgresql'),
76 )
77 return table