diff -r b66fe349cd2a trytond/trytond/modules/analytic_account/line.py
--- a/trytond/trytond/modules/analytic_account/line.py	Thu Feb 21 00:13:13 2019 +0100
+++ b/trytond/trytond/modules/analytic_account/line.py	Thu Feb 21 00:14:32 2019 +0100
@@ -44,9 +44,8 @@
         super(Line, cls).__setup__()
         t = cls.__table__()
         cls._sql_constraints += [
-            ('credit_debit',
-                Check(t,
-                    (t.credit * t.debit == 0) & (t.credit + t.debit >= 0)),
+            ('credit_debit_',
+                Check(t, t.credit * t.debit == 0),
                 'Wrong credit/debit values.'),
             ]
         cls._error_messages.update({
@@ -71,6 +70,9 @@
         for field_name in ['name', 'journal']:
             table.not_null_action(field_name, action='remove')

+        # Migration from 5.0: replace credit_debit constraint by credit_debit_
+        table.drop_constraint('credit_debit')
+
     @staticmethod
     def default_date():
         Date = Pool().get('ir.date')