I have asked for this a few months.
Here's my own first version for an ORM.
It's adapted from SQLAlchemy and SQLObject.
(and whatever library I have searched)
You need to create a database manually first.
My previous snippets (
shell,
SQL) may help.
1
2 from __future__ import generators
3 import e32db, re
4 db = e32db.Dbms()
5 dbv = e32db.Db_view()
6 db.open(u'C:\\test.db')
7
8
9 class String:
10 pass
11
12 class Integer:
13 pass
14
15 class Float:
16 pass
17
18 class column:
19 def __init__(self, coltype):
20 self.coltype = coltype
Here's the mother of all your classes that map to database tables.
1
2 class Mapper(object):
3 def __init__(self, id=None, **kw):
4 if id is None:
5 self.id = self._insert(**kw)
6 else:
7 self.id = id
8 def _insert(self, **kw):
9 names = ','.join(kw.keys())
10 values = ','.join([self.quote(k,v) for k,v in kw.items()])
11 tablename = self.__class__.__name__
12 q = u"INSERT INTO %s(%s) VALUES (%s)" % (tablename, names, values)
13 db.execute(q)
14
15 dbv.prepare(db, u'SELECT id FROM '+tablename+' ORDER BY id DESC')
16 dbv.first_line()
17 dbv.get_line()
18 return dbv.col(1)
19 def __getattr__(self, name):
20 if name in self.mapping.__dict__:
21 q = 'SELECT '+name+' FROM '+self.__class__.__name__
22 q += ' WHERE id='+str(self.id)
23 dbv.prepare(db, unicode(q))
24 dbv.first_line()
25 dbv.get_line()
26 return dbv.col(1)
27 else:
28 return self.__dict__[name]
29 def __repr__(self):
30 return '<%s id=%d>' % (self.__class__.__name__, self.id)
31 def quote(self, name, value):
32 if self.mapping.__dict__[name].coltype == String:
33 return "'%s'" % value.replace("'", "''")
34 else:
35 return str(value)
36 def __setattr__(self, name, value):
37 if name in self.mapping.__dict__:
38 q = 'UPDATE '+self.__class__.__name__+' SET '+name+'='
39 q += self.quote(name, value) + " WHERE id=" + str(self.id)
40 db.execute(unicode(q))
41 else:
42 self.__dict__[name] = value
43 def set(self, **kw):
44 q = "UPDATE "+self.__class__.__name__+" SET "
45 for k, v in kw.items():
46 q += k+'='+self.quote(k,v)+','
47 q = q[:-1]+" WHERE id=%s" % self.id
48 db.execute(unicode(q))
49 def delete(self):
50 q = 'DELETE FROM '+self.__class__.__name__+" WHERE id=" + str(self.id)
51 db.execute(unicode(q))
52 self.id = None
53 def dict(self):
54 names = [k for k in self.mapping.__dict__.keys() if not k.startswith('__')]
55 q = 'SELECT '+','.join(names)+' FROM '+self.__class__.__name__
56 q += ' WHERE id=' + str(self.id)
57 dbv.prepare(db, unicode(q))
58 dbv.first_line()
59 dbv.get_line()
60 dct = {'id': self.id}
61 for i in range(dbv.col_count()):
62 dct[names[i]] = dbv.col(i+1)
63 return dct
64 def select(cls, where=None, orderby=None):
65 q = 'SELECT id FROM '+cls.__name__
66 if where:
67 q += ' WHERE '+where
68 if orderby:
69 q += ' ORDER BY '+orderby
70 dbv = e32db.Db_view()
71 dbv.prepare(db, unicode(q))
72 dbv.first_line()
73 for i in range(dbv.count_line()):
74 dbv.get_line()
75 yield cls(dbv.col(1))
76 dbv.next_line()
77 select = classmethod(select)
Here's how you create your class.
1
2 class Person(Mapper):
3 class mapping:
4
5 name = column(String)
6 age = column(Integer)
