[Sqlalchemy-tickets] Issue #3345: Naming conventions example should use columns_0_name (zzzeek/sqlalchemy)

[Thomas T. <iss...@bi...>]

New issue 3345: Naming conventions example should use columns_0_name
https://bitbucket.org/zzzeek/sqlalchemy/issue/3345/naming-conventions-example-should-use

Thomas Tanner:

The example
http://docs.sqlalchemy.org/en/latest/core/constraints.html#configuring-constraint-naming-conventions


```
#!python

convention = {
  "ix": 'ix_%(column_0_label)s',
  "uq": "uq_%(table_name)s_%(column_0_name)s",
  "ck": "ck_%(table_name)s_%(constraint_name)s",
  "fk": "fk_%(table_name)s_%(column_0_name)s_%(referred_table_name)s",
  "pk": "pk_%(table_name)s"
}

```
should be changed to   "ck": "ck_%(table_name)s_%(column_0_name)s",
Otherwise unnamed constraints (for example, Boolean) raise

sqlalchemy.exc.InvalidRequestError: Naming convention including %(constraint_name)s token requires that constraint is explicitly named.