Allow creation of foreign key on non primary key

trytond/CHANGELOG

@@ -1,3 +1,4 @@
+* Allow creation of foreign key on non primary key
 * Include context information in access error
 * Remove trytond-worker max tasks per child option for Python <= 3.10
 * Do not copy readonly relational fields

trytond/doc/ref/backend.rst

@@ -279,15 +279,16 @@ TableHandler
    The ``default`` is a method that return the value to fill the new column.
    ``comment`` set as comment for the column.
 
-.. method:: TableHandler.add_fk(column_name, reference[, on_delete])
+.. method:: TableHandler.add_fk(columns, reference[, ref_columns[, on_delete])
 
-   Add a foreign key constraint on the named column to target the ``reference``
-   table name.
+   Add a foreign key constraint on the named columns to target the
+   ``ref_columns`` of ``reference`` table name.
    ``on_delete`` defines the method to use when foreign record is deleted.
 
-.. method:: TableHandler.drop_fk(column_name[, table])
+.. method:: TableHandler.drop_fk(columns[, ref_columns[, table])
 
-   Drop the foreign key constrant on the named column.
+   Drop the foreign key constraint on the named columns targeting the
+   ``ref_columns``.
    ``table`` can be used to alter another table.
 
 .. method:: TableHandler.not_null_action(column_name[, action])

trytond/trytond/backend/postgresql/table.py

@@ -396,40 +396,63 @@ class TableHandler(TableHandlerInterface):
 
         self._update_definitions(columns=True)
 
-    def add_fk(self, column_name, reference, on_delete=None):
+    def add_fk(self, columns, reference, ref_columns=None, on_delete=None):
         if on_delete is not None:
             on_delete = on_delete.upper()
         else:
             on_delete = 'SET NULL'
+        if isinstance(columns, str):
+            columns = [columns]
 
         cursor = Transaction().connection.cursor()
-        name = self.convert_name(self.table_name + '_' + column_name + '_fkey')
+        if ref_columns:
+            ref_columns_name = '_' + '_'.join(ref_columns)
+        else:
+            ref_columns_name = ''
+        name = self.convert_name(
+            self.table_name + '_' + '_'.join(columns)
+            + ref_columns_name + '_fkey')
         if name in self._constraints:
-            if self._fk_deltypes.get(column_name) != on_delete:
-                self.drop_fk(column_name)
-                add = True
+            for column_name in columns:
+                if self._fk_deltypes.get(column_name) != on_delete:
+                    self.drop_fk(columns, ref_columns)
+                    add = True
+                    break
             else:
                 add = False
         else:
             add = True
         if add:
+            columns = SQL(', ').join(map(Identifier, columns))
+            if not ref_columns:
+                ref_columns = ['id']
+            ref_columns = SQL(', ').join(map(Identifier, ref_columns))
             cursor.execute(
                 SQL(
                     "ALTER TABLE {table} "
                     "ADD CONSTRAINT {constraint} "
-                    "FOREIGN KEY ({column}) REFERENCES {reference} "
+                    "FOREIGN KEY ({columns}) "
+                    "REFERENCES {reference} ({ref_columns}) "
                     "ON DELETE {action}"
                     )
                 .format(
                     table=Identifier(self.table_name),
                     constraint=Identifier(name),
-                    column=Identifier(column_name),
+                    columns=columns,
                     reference=Identifier(reference),
+                    ref_columns=ref_columns,
                     action=SQL(on_delete)))
             self._update_definitions(constraints=True)
 
-    def drop_fk(self, column_name, table=None):
-        self.drop_constraint(column_name + '_fkey', table=table)
+    def drop_fk(self, columns, ref_columns=None, table=None):
+        if isinstance(columns, str):
+            columns = [columns]
+        if ref_columns:
+            ref_columns_name = '_' + '_'.join(ref_columns)
+        else:
+            ref_columns_name = ''
+        self.drop_constraint(
+            '_'.join(columns) + ref_columns_name + '_fkey', table=table)
 
     def not_null_action(self, column_name, action='add'):
         if not self.column_exist(column_name):

trytond/trytond/backend/sqlite/table.py

@@ -255,10 +255,10 @@ class TableHandler(TableHandlerInterface):
 
         self._update_definitions(columns=True)
 
-    def add_fk(self, column_name, reference, on_delete=None):
+    def add_fk(self, columns, reference, ref_columns=None, on_delete=None):
         warnings.warn('Unable to add foreign key with SQLite backend')
 
-    def drop_fk(self, column_name, table=None):
+    def drop_fk(self, columns=None, ref_columns=None, table=None):
         warnings.warn('Unable to drop foreign key with SQLite backend')
 
     def not_null_action(self, column_name, action='add'):

trytond/trytond/backend/table.py

@@ -70,10 +70,10 @@ class TableHandlerInterface(object):
     def add_column(self, column_name, abstract_type, default=None, comment=''):
         raise NotImplementedError
 
-    def add_fk(self, column_name, reference, on_delete=None):
+    def add_fk(self, columns, reference, ref_columns=None, on_delete=None):
         raise NotImplementedError
 
-    def drop_fk(self, column_name, table=None):
+    def drop_fk(self, columns, ref_columns=None, table=None):
         raise NotImplementedError
 
     def not_null_action(self, column_name, action='add'):

trytond/trytond/model/modelsql.py

@@ -454,7 +454,7 @@ class ModelSQL(ModelStorage):
                     # migration from 3.6
                     table.drop_fk(field_name)
                 elif ref:
-                    table.add_fk(field_name, ref, field.ondelete)
+                    table.add_fk(field_name, ref, on_delete=field.ondelete)
 
             required = field.required
             # Do not set 'NOT NULL' for Binary field as the database column