diff --git a/tests/unit/test_database.py b/tests/unit/test_database.py
index f22be4769..45cb029cd 100644
--- a/tests/unit/test_database.py
+++ b/tests/unit/test_database.py
@@ -11,53 +11,66 @@ from .test_transaction import get_output, NULL_HASH
 
 class TestConstraintBuilder(unittest.TestCase):
 
+    def test_dot(self):
+        constraints = {'txo.position': 18}
+        self.assertEqual(
+            constraints_to_sql(constraints, prepend_sql=''),
+            'txo.position = :txo_position'
+        )
+        self.assertEqual(constraints, {'txo_position': 18})
+
     def test_any(self):
         constraints = {
             'ages__any': {
-                'age__gt': 18,
-                'age__lt': 38
+                'txo.age__gt': 18,
+                'txo.age__lt': 38
             }
         }
         self.assertEqual(
             constraints_to_sql(constraints, prepend_sql=''),
-            '(age > :ages__any_age__gt OR age < :ages__any_age__lt)'
+            '(txo.age > :ages__any_txo_age__gt OR txo.age < :ages__any_txo_age__lt)'
         )
         self.assertEqual(
             constraints, {
-                'ages__any_age__gt': 18,
-                'ages__any_age__lt': 38
+                'ages__any_txo_age__gt': 18,
+                'ages__any_txo_age__lt': 38
             }
         )
 
     def test_in_list(self):
-        constraints = {'ages__in': [18, 38]}
+        constraints = {'txo.age__in': [18, 38]}
         self.assertEqual(
             constraints_to_sql(constraints, prepend_sql=''),
-            'ages IN (:ages_1, :ages_2)'
+            'txo.age IN (:txo_age_1, :txo_age_2)'
         )
         self.assertEqual(
             constraints, {
-                'ages_1': 18,
-                'ages_2': 38
+                'txo_age_1': 18,
+                'txo_age_2': 38
             }
         )
 
     def test_in_query(self):
-        constraints = {'ages__in': 'SELECT age from ages_table'}
+        constraints = {'txo.age__in': 'SELECT age from ages_table'}
         self.assertEqual(
             constraints_to_sql(constraints, prepend_sql=''),
-            'ages IN (SELECT age from ages_table)'
+            'txo.age IN (SELECT age from ages_table)'
         )
         self.assertEqual(constraints, {})
 
     def test_not_in_query(self):
-        constraints = {'ages__not_in': 'SELECT age from ages_table'}
+        constraints = {'txo.age__not_in': 'SELECT age from ages_table'}
         self.assertEqual(
             constraints_to_sql(constraints, prepend_sql=''),
-            'ages NOT IN (SELECT age from ages_table)'
+            'txo.age NOT IN (SELECT age from ages_table)'
         )
         self.assertEqual(constraints, {})
 
+    def test_in_invalid(self):
+        constraints = {'ages__in': 9}
+        with self.assertRaisesRegex(ValueError, 'list or string'):
+            constraints_to_sql(constraints, prepend_sql='')
+
 
 class TestQueries(unittest.TestCase):
 
diff --git a/torba/__init__.py b/torba/__init__.py
index 2123d238e..c5362f6e8 100644
--- a/torba/__init__.py
+++ b/torba/__init__.py
@@ -1,2 +1,2 @@
 __path__: str = __import__('pkgutil').extend_path(__path__, __name__)
-__version__ = '0.0.5'
+__version__ = '0.0.7'
diff --git a/torba/basedatabase.py b/torba/basedatabase.py
index 8dd65d8f6..375fa4337 100644
--- a/torba/basedatabase.py
+++ b/torba/basedatabase.py
@@ -11,12 +11,16 @@ from torba.basetransaction import BaseTransaction, TXORefResolvable
 log = logging.getLogger(__name__)
 
 
+def clean_arg_name(arg):
+    return arg.replace('.', '_')
+
+
 def constraints_to_sql(constraints, joiner=' AND ', prepend_sql=' AND ', prepend_key=''):
     if not constraints:
         return ''
     extras = []
     for key in list(constraints):
-        col, op = key, '='
+        col, op, constraint = key, '=', constraints.pop(key)
         if key.endswith('__not'):
             col, op = key[:-len('__not')], '!='
         elif key.endswith('__lt'):
@@ -32,24 +36,27 @@ def constraints_to_sql(constraints, joiner=' AND ', prepend_sql=' AND ', prepend
                 col, op = key[:-len('__in')], 'IN'
             else:
                 col, op = key[:-len('__not_in')], 'NOT IN'
-            items = constraints.pop(key)
-            if isinstance(items, list):
+            if isinstance(constraint, list):
                 placeholders = []
-                for item_no, item in enumerate(items, 1):
-                    constraints['{}_{}'.format(col, item_no)] = item
-                    placeholders.append(':{}_{}'.format(col, item_no))
+                for item_no, item in enumerate(constraint, 1):
+                    constraints['{}_{}'.format(clean_arg_name(col), item_no)] = item
+                    placeholders.append(':{}_{}'.format(clean_arg_name(col), item_no))
                 items = ', '.join(placeholders)
+            elif isinstance(constraint, str):
+                items = constraint
+            else:
+                raise ValueError("{} requires a list or string as constraint value.".format(key))
             extras.append('{} {} ({})'.format(col, op, items))
             continue
         elif key.endswith('__any'):
-            subconstraints = constraints.pop(key)
             extras.append('({})'.format(
-                constraints_to_sql(subconstraints, ' OR ', '', key+'_')
+                constraints_to_sql(constraint, ' OR ', '', key+'_')
             ))
-            for subkey, val in subconstraints.items():
-                constraints['{}_{}'.format(key, subkey)] = val
+            for subkey, val in constraint.items():
+                constraints['{}_{}'.format(clean_arg_name(key), clean_arg_name(subkey))] = val
             continue
-        extras.append('{} {} :{}'.format(col, op, prepend_key+key))
+        constraints[clean_arg_name(key)] = constraint
+        extras.append('{} {} :{}'.format(col, op, prepend_key+clean_arg_name(key)))
     return prepend_sql + joiner.join(extras) if extras else ''