web2py/web2py — pull request #550 by ilvalle (2014-11-30 19:07:56+00:00)
Title: Fix NULL values with SQLCustomType

An initial fix for SQLCustomType, the current implementation stores 'None' instead of 'NULL'
Example test:
```
db = DAL('sqlite://memory')
from gluon.dal.helpers.classes import SQLCustomType
simple_t = SQLCustomType(
type = "double",
native = "double",
)
db.define_table('product',
Field("price_base", "double"),
Field("price_custom", simple_t),
)
db.product.insert(price_base=None)
db.product.insert(price_custom=None)
```
The first insert works, the second fails.