Fix SQLAlchemy raw SQL errors in database connections

- Add proper import of sqlalchemy.text in session.py
- Update raw SQL query execution to use text() function
- Enhance error messages with specific guidance for common SQLAlchemy errors
- Add more detailed logging of error types for easier debugging
- Ensure compatibility with newer SQLAlchemy versions

app/db/session.py

@@ -3,7 +3,7 @@ import sqlite3
 import os
 from typing import Generator
 
-from sqlalchemy import create_engine, event
+from sqlalchemy import create_engine, event, text
 from sqlalchemy.orm import sessionmaker
 
 from app.core.config import settings, DB_DIR
@@ -88,6 +88,8 @@ def optimize_sqlite_connection(dbapi_connection, connection_record):
     """Configure SQLite connection for better reliability."""
     try:
         # These are essential for SQLite stability
+        # Note: We use raw SQL here because these are SQLite-specific PRAGMA commands
+        # They are executed at the DBAPI level, not through SQLAlchemy ORM
         dbapi_connection.execute("PRAGMA journal_mode=WAL")
         dbapi_connection.execute("PRAGMA synchronous=NORMAL")
     except Exception as e:
@@ -113,7 +115,7 @@ def get_db() -> Generator:
             print(f"Database connection attempt {attempt + 1}")
 
             # Test connection with a simple query
-            db.execute("SELECT 1")
+            db.execute(text("SELECT 1"))
 
             # Connection succeeded
             print("Database connection successful")
@@ -126,12 +128,22 @@ def get_db() -> Generator:
                 db.close()
                 db = None
 
-            error_msg = f"Database connection attempt {attempt + 1} failed: {e}"
+            # Provide more detailed error messages for common issues
+            if isinstance(e, ImportError) and "No module named" in str(e):
+                error_msg = f"Database connection failed due to missing module: {e}. Please check requirements.txt and install missing dependencies."
+            elif "no such table" in str(e).lower():
+                error_msg = f"Database connection failed: Table doesn't exist: {e}. Make sure to run all migrations with 'alembic upgrade head'."
+            elif "sqlalchemy.exc.argumenterror" in str(e).lower():
+                error_msg = f"Database connection failed: SQLAlchemy Argument Error: {e}. Make sure all raw SQL is wrapped with text()."
+            else:
+                error_msg = f"Database connection attempt {attempt + 1} failed: {e}"
+
             print(error_msg)
 
             # Log critical error details
             import traceback
 
+            print(f"Error type: {type(e).__name__}")
             print(f"Error traceback: {traceback.format_exc()}")
 
             # Check if we can directly access database