[Sqlalchemy-tickets] Issue #4075: multi-valued insert invokes default for same column many times (zzzeek/sqlalchemy)

[Michael B. <iss...@bi...>]

New issue 4075: multi-valued insert invokes default for same column many times
https://bitbucket.org/zzzeek/sqlalchemy/issues/4075/multi-valued-insert-invokes-default-for

Michael Bayer:

this case can't be handled without adding additional context:


```
#!python

from sqlalchemy import *

m = MetaData()


def my_default(context):
    print "Called!  What index are we? current params: %s" % context.current_parameters
    return 0

t = Table('t', m, Column('x', Integer), Column('y', Integer, default=my_default))

e = create_engine("mysql://scott:tiger@localhost/test")


m.create_all(e)

e.execute(t.insert().values([{"x": 5}, {"x": 6}, {"x": 7}]))




```



```
#!python

Called!  What index are we? current params: {u'y_m2': None, u'y_m1': None, u'x_m0': 5, u'x_m1': 6, u'x_m2': 7, 'y': None}
Called!  What index are we? current params: {u'y_m2': None, u'y_m1': None, u'x_m0': 5, u'x_m1': 6, u'x_m2': 7, 'y': 0}
Called!  What index are we? current params: {u'y_m2': None, u'y_m1': 0, u'x_m0': 5, u'x_m1': 6, u'x_m2': 7, 'y': 0}

```

will add new method.