diff --git a/openerp/addons/base/ir/ir_model.py b/openerp/addons/base/ir/ir_model.py
index 70056383090..9e7697c1bbb 100644
--- a/openerp/addons/base/ir/ir_model.py
+++ b/openerp/addons/base/ir/ir_model.py
@@ -263,7 +263,6 @@ class ir_model_fields(osv.osv):
         'state': lambda self,cr,uid,ctx=None: (ctx and ctx.get('manual',False)) and 'manual' or 'base',
         'on_delete': 'set null',
         'select_level': '0',
-        'size': 64,
         'field_description': '',
         'selectable': 1,
     }
@@ -293,10 +292,10 @@ class ir_model_fields(osv.osv):
         return True
 
     def _size_gt_zero_msg(self, cr, user, ids, context=None):
-        return _('Size of the field can never be less than 1 !')
+        return _('Size of the field can never be less than 0 !')
 
     _sql_constraints = [
-        ('size_gt_zero', 'CHECK (size>0)',_size_gt_zero_msg ),
+        ('size_gt_zero', 'CHECK (size>=0)',_size_gt_zero_msg ),
     ]
 
     def _drop_column(self, cr, uid, ids, context=None):
diff --git a/openerp/addons/base/ir/ir_model_view.xml b/openerp/addons/base/ir/ir_model_view.xml
index 0f13837a65a..15052e6e5c5 100644
--- a/openerp/addons/base/ir/ir_model_view.xml
+++ b/openerp/addons/base/ir/ir_model_view.xml
@@ -151,7 +151,7 @@
                                                                           'readonly': [('ttype','not in', ['many2one','one2many','many2many'])]}"/>
                             <field name="relation_field" attrs="{'required': [('ttype','=','one2many')], 'readonly': [('ttype','!=','one2many')]}"/>
                             <field name="selection" attrs="{'required': [('ttype','in',['selection','reference'])], 'readonly': [('ttype','not in',['selection','reference'])]}"/>
-                            <field name="size" attrs="{'required': [('ttype','in',['char','reference'])], 'readonly': [('ttype','not in',['char','reference'])]}"/>
+                            <field name="size" attrs="{'invisible': [('ttype','not in',['char','text','reference'])]}"/>
                             <field name="domain" attrs="{'readonly': [('relation','=','')]}"/>
                             <field name="serialization_field_id" attrs="{'readonly': [('state','=','base')]}" domain="[('ttype','=','serialized'), ('model_id', '=', model_id)]"/>
                             <field name="on_delete" attrs="{'readonly': [('ttype','!=','many2one')]}"/>
diff --git a/openerp/osv/orm.py b/openerp/osv/orm.py
index 61f1a83c040..63892297578 100644
--- a/openerp/osv/orm.py
+++ b/openerp/osv/orm.py
@@ -1029,7 +1029,7 @@ class BaseModel(object):
                 'required': bool(field['required']),
                 'readonly': bool(field['readonly']),
                 'domain': eval(field['domain']) if field['domain'] else None,
-                'size': field['size'],
+                'size': field['size'] or None,
                 'ondelete': field['on_delete'],
                 'translate': (field['translate']),
                 'manual': True,