Add PostgreSQL version of SQLite integ tests

- Add PostgreSQL throwaway database
- Add optional length parameter for random string
- Fix syntax for PostgreSQL in several areas
- Add optional ID for whereById type determination

tests/unit/Query/PatchTest.php

@@ -49,7 +49,7 @@ class PatchTest extends TestCase
     {
         try {
             Configuration::$mode = Mode::PgSQL;
-            $this->assertEquals("UPDATE that SET data = data || :data WHERE data->>'something' < :some",
+            $this->assertEquals("UPDATE that SET data = data || :data WHERE (data->>'something')::numeric < :some",
                 Patch::byFields('that', [Field::LT('something', 17, ':some')]),
                 'Patch UPDATE statement is not correct');
         } finally {