From: Christian Heller <c.heller@plomlompom.de>
Date: Wed, 24 Apr 2024 23:52:46 +0000 (+0200)
Subject: Check for database file's DB version (via user_version PRAGMA).
X-Git-Url: https://plomlompom.com/repos/%7B%7Bprefix%7D%7D/static/%7B%7B%20web_path%20%7D%7D/blog?a=commitdiff_plain;h=87505e3be37ad7a208c8f77dc7d7631728d87fa4;p=plomtask

Check for database file's DB version (via user_version PRAGMA).
---

diff --git a/plomtask/db.py b/plomtask/db.py
index 848e750..dd2ee24 100644
--- a/plomtask/db.py
+++ b/plomtask/db.py
@@ -6,6 +6,7 @@ from typing import Any, Dict
 from plomtask.exceptions import HandledException
 
 PATH_DB_SCHEMA = 'scripts/init.sql'
+EXPECTED_DB_VERSION = 0
 
 
 class DatabaseFile:  # pylint: disable=too-few-public-methods
@@ -23,11 +24,22 @@ class DatabaseFile:  # pylint: disable=too-few-public-methods
         self._check()
 
     def _check(self) -> None:
-        """Check file exists, and is of proper schema."""
+        """Check file exists, and is of proper DB version and schema."""
         self.exists = isfile(self.path)
         if self.exists:
+            self._validate_user_version()
             self._validate_schema()
 
+    def _validate_user_version(self) -> None:
+        """Compare DB user_version with EXPECTED_DB_VERSION."""
+        sql_for_db_version = 'PRAGMA user_version'
+        with sql_connect(self.path) as conn:
+            db_version = list(conn.execute(sql_for_db_version))[0][0]
+            if db_version != EXPECTED_DB_VERSION:
+                msg = f'Wrong DB version, expected '\
+                        f'{EXPECTED_DB_VERSION}, got {db_version}.'
+                raise HandledException(msg)
+
     def _validate_schema(self) -> None:
         """Compare found schema with what's stored at PATH_DB_SCHEMA."""
         sql_for_schema = 'SELECT sql FROM sqlite_master ORDER BY sql'