Update app.py

app.py

@@ -11,9 +11,9 @@ app = Flask(__name__)
 app.secret_key = os.urandom(24)  # Required for session management
 load_dotenv()
 
-# Default database configuration from .env
+# Default database configuration from .env (no localhost default)
 default_db_config = {
-    'host': os.getenv('DB_HOST', 'localhost'),
+    'host': os.getenv('DB_HOST', ''),
     'user': os.getenv('DB_USER', 'root'),
     'password': os.getenv('DB_PASSWORD', ''),
     'port': int(os.getenv('DB_PORT', 3306))
@@ -34,13 +34,15 @@ current_summary = {}
 def get_db_connection(db_name=None):
     """Establish a database connection using session or default config."""
     config = session.get('db_config', default_db_config).copy()
+    if not config['host'] or not config['user']:
+        return None, "Please configure a valid MySQL connection using the 'Configure MySQL Connection' modal."
     if db_name:
         config['database'] = db_name
     try:
         conn = mysql.connector.connect(**config)
         return conn, None
     except Error as e:
-        return None, f"Database connection failed: {str(e)}"
+        return None, f"Database connection failed: {str(e)}. Ensure the MySQL server is running and accessible, and check your credentials."
 
 def parse_sql_file(file_content):
     """Parse SQL file to extract database name and clean statements."""