Codegen: ignore `synth` properties in `dbschemegen`

misc/codegen/generators/dbschemegen.py

@@ -49,7 +49,7 @@ def cls_to_dbscheme(cls: schema.Class, lookup: typing.Dict[str, schema.Class], a
     # Leaf classes need a table to bind the `@` ids
     # 1-to-1 properties are added to a class specific table
     # in other cases, separate tables are used for the properties, and a class specific table is unneeded
-    if not cls.derived or any(f.is_single for f in cls.properties):
+    if not cls.derived or any(f.is_single and not f.synth for f in cls.properties):
         binding = not cls.derived
         keyset = KeySet(["id"]) if cls.derived else None
         yield Table(
@@ -58,12 +58,15 @@ def cls_to_dbscheme(cls: schema.Class, lookup: typing.Dict[str, schema.Class], a
             columns=[
                 Column("id", type=dbtype(cls.name), binding=binding),
             ] + [
-                Column(f.name, dbtype(f.type, add_or_none_except)) for f in cls.properties if f.is_single
+                Column(f.name, dbtype(f.type, add_or_none_except))
+                for f in cls.properties if f.is_single and not f.synth
             ],
             dir=dir,
         )
     # use property-specific tables for 1-to-many and 1-to-at-most-1 properties
     for f in cls.properties:
+        if f.synth:
+            continue
         if f.is_unordered:
             yield Table(
                 name=inflection.tableize(f"{cls.name}_{f.name}"),

misc/codegen/test/test_dbschemegen.py

@@ -566,5 +566,32 @@ def test_ipa_derived_classes_ignored(generate):
     )
 
 
+def test_synth_properties_ignored(generate):
+    assert generate([
+        schema.Class(name="A", properties=[
+            schema.SingleProperty("x", "a"),
+            schema.SingleProperty("y", "b", synth=True),
+            schema.SingleProperty("z", "c"),
+            schema.OptionalProperty("foo", "bar", synth=True),
+            schema.RepeatedProperty("baz", "bazz", synth=True),
+            schema.RepeatedOptionalProperty("bazzz", "bazzzz", synth=True),
+            schema.RepeatedUnorderedProperty("bazzzzz", "bazzzzzz", synth=True),
+        ]),
+    ]) == dbscheme.Scheme(
+        src=schema_file.name,
+        includes=[],
+        declarations=[
+            dbscheme.Table(
+                name="as",
+                columns=[
+                    dbscheme.Column("id", "@a", binding=True),
+                    dbscheme.Column("x", "a"),
+                    dbscheme.Column("z", "c"),
+                ],
+            )
+        ],
+    )
+
+
 if __name__ == '__main__':
     sys.exit(pytest.main([__file__] + sys.argv[1:]))