Create _schema_exists method

gramps/gen/db/generic.py

@@ -625,9 +625,7 @@ class DbGeneric(DbWriteBase, DbReadBase, UpdateCallback, Callback):
         # run backend-specific code:
         self._initialize(directory, username, password)
 
-        # We use the existence of the person table as a proxy for the database
-        # being new
-        if not self.dbapi.table_exists("person"):
+        if not self._schema_exists():
             self._create_schema()
             self._set_metadata('version', str(self.VERSION[0]))
 

gramps/plugins/db/dbapi/dbapi.py

@@ -56,6 +56,15 @@ class DBAPI(DbGeneric):
     def _initialize(self, directory, username, password):
         raise NotImplementedError
 
+    def _schema_exists(self):
+        """
+        Check to see if the schema exists.
+
+        We use the existence of the person table as a proxy for the database
+        being new.
+        """
+        return self.dbapi.table_exists("person")
+
     def _create_schema(self):
         """
         Create and update schema.