Exception handling for database queries

ref-test/app/view/views.py

@@ -2,10 +2,12 @@ from ..forms.admin import EditDataset
 from ..models import Dataset, User
 from ..tools.forms import get_dataset_choices, send_errors_to_client
 from ..tools.data import check_dataset_exists
+from ..tools.logs import write
 
-from flask import Blueprint, flash, jsonify, redirect, render_template, request
-from flask.helpers import url_for
+from flask import Blueprint, jsonify, render_template, request
+from flask.helpers import abort, flash, redirect, url_for
 from flask_login import login_required
+from sqlalchemy.exc import SQLAlchemyError
 
 view = Blueprint(
     name='view',
@@ -32,9 +34,13 @@ def _view():
 @login_required
 @check_dataset_exists
 def _view_console(id:str=None):
-    dataset = Dataset.query.filter_by(id=id).first()
-    datasets = Dataset.query.count()
-    users = User.query.all()
+    try:
+        dataset = Dataset.query.filter_by(id=id).first()
+        datasets = Dataset.query.count()
+        users = User.query.all()
+    except SQLAlchemyError as exception:
+            write('system.log', f'Database error when processing request \'{request.url}\': {exception}')
+            return abort(500)
     if not dataset:
         flash('Invalid dataset ID.', 'error')
         return redirect(url_for('admin._questions'))