Add __table_handler__ to ModelSQL

issue7581
review48531002

account.py

@@ -117,9 +117,8 @@ class Account(
 
     @classmethod
     def __register__(cls, module_name):
-        TableHandler = backend.get('TableHandler')
         super(Account, cls).__register__(module_name)
-        table = TableHandler(cls, module_name)
+        table = cls.__table_handler__(module_name)
 
         # Migration from 4.0: remove currency
         table.not_null_action('currency', action='remove')
@@ -424,7 +423,7 @@ class AnalyticAccountEntry(ModelView, ModelSQL):
             migration_3_4 = True
 
         # Don't create table before renaming
-        table = TableHandler(cls, module_name)
+        table = cls.__table_handler__(module_name)
 
         super(AnalyticAccountEntry, cls).__register__(module_name)
 
@@ -515,12 +514,11 @@ class AnalyticMixin(object):
     def __register__(cls, module_name):
         pool = Pool()
         AccountEntry = pool.get('analytic.account.entry')
-        TableHandler = backend.get('TableHandler')
         cursor = Transaction().connection.cursor()
 
         super(AnalyticMixin, cls).__register__(module_name)
 
-        handler = TableHandler(cls, module_name)
+        handler = cls.__table_handler__(module_name)
         # Migration from 3.4: analytic accounting changed to reference field
         if handler.column_exist('analytic_accounts'):
             entry = AccountEntry.__table__()

line.py

@@ -7,7 +7,6 @@ from sql import Literal
 
 from trytond.model import ModelView, ModelSQL, fields, Check
 from trytond.wizard import Wizard, StateAction
-from trytond import backend
 from trytond.pyson import Eval, PYSONEncoder
 from trytond.transaction import Transaction
 from trytond.pool import Pool, PoolMeta
@@ -60,9 +59,8 @@ class Line(ModelSQL, ModelView):
 
     @classmethod
     def __register__(cls, module_name):
-        TableHandler = backend.get('TableHandler')
         super(Line, cls).__register__(module_name)
-        table = TableHandler(cls, module_name)
+        table = cls.__table_handler__(module_name)
 
         # Migration from 1.2 currency has been changed in function field
         table.not_null_action('currency', action='remove')
@@ -209,8 +207,7 @@ class MoveLine(ModelSQL, ModelView):
 
     @classmethod
     def __register__(cls, module_name):
-        TableHandler = backend.get('TableHandler')
-        table = TableHandler(cls, module_name)
+        table = cls.__table_handler__(module_name)
         cursor = Transaction().connection.cursor()
         sql_table = cls.__table__()