Introduce batch push-down to database connections (#7)

* Fix asynchronous record iterator exhausted when scanning for new enumeration values

* Introduce batch push-down to database connections

* Eliminate duplicate code

* Add guard to prevent re-using an already exhausted iterator

.vscode/settings.json

@@ -15,10 +15,10 @@
         "black"
     ],
     "python.analysis.typeCheckingMode": "off",
+    "python.analysis.diagnosticSeverityOverrides": {
+        "reportInvalidTypeForm": "none"
+    },
     "[python]": {
         "editor.defaultFormatter": "ms-python.black-formatter"
-    },
-    "cSpell.words": [
-        "unsync"
-    ]
+    }
 }

check.sh

@@ -1,7 +1,9 @@
 set -e
 
+PYTHON=python3
+
 # Run static type checker and verify formatting guidelines
-python3 -m mypy pysqlsync
-python3 -m flake8 pysqlsync
-python3 -m mypy tests
-python3 -m flake8 tests
+$PYTHON -m mypy pysqlsync
+$PYTHON -m flake8 pysqlsync
+$PYTHON -m mypy tests
+$PYTHON -m flake8 tests