Flask and sqlite: Failing to insert values into the database - database

Question

I have the following code in the main.py file. It appears to work in all instances, note when I print out user_details, it prints out the tuple: test,test,test (filled in to the form), so the post request is working. However, somehow, it is not being actually written to the database.
Main nature of error: The insertion is not taking place.
Can someone spot an error in my code?
#ADD COMMENT GET POST REQUEST FUNCTION
#app.route('/add',methods=['GET','POST'])
def addcomment():
if request.method=="GET":
return render_template('addcomment.html')
else:
user_details=(
request.form['title'],
request.form['name'],
request.form['comment']
)
#print(user_details)
insertcomment(user_details)
return render_template('addsuccess.html')
#INSERTING comments into the actual database
def insertcomment(user_details):
connie = sqlite3.connect(db_locale)
c=connie.cursor()
sql_insert_string='INSERT INTO comments (title, name, comment) VALUES (?,?,?)';
c.execute(sql_insert_string,user_details)
connie.commit
connie.close()
print(user_details)
def query_comments():
connie = sqlite3.connect(db_locale)
c=connie.cursor()
c.execute("""
SELECT * FROM comments
""")
userdata=c.fetchall()
return userdata
My suspicion is that there is something wrong with these lines (that is the second function)
insertcomment()
connie = sqlite3.connect(db_locale)
c=connie.cursor()
sql_insert_string='INSERT INTO comments (title, name, comment) VALUES (?,?,?)';
c.execute(sql_insert_string,user_details)
The def addcomment(): function works fine as far as I can see, rendering and returning the right html page on clicking submit.
On the html side, the only thing I can think of that MAY be causing an error is the order of the fields. In the database the fields are Name, Title, Comment (in that order), but in the HTML and the query, they are Title, Name, Comment (in that order specified).
For reference, the HTML file (the form that accepts that data) is below:
<div class="form-group">
<label for="exampleInputEmail1">Title (or catchy caption!)</label>
<input type="text" class="form-control" id="title" name="title" aria-describedby="emailHelp">
</div>
<div class="form-group">
<label for="exampleInputPassword1">Name</label>
<input type="text" class="form-control" id="name" name="name">
</div>
<div class="form-group">
<label for="exampleFormControlTextarea1">Add your amazing answer here:</label>
<textarea class="form-control" id="comment" name="comment" rows="3"></textarea>
</div>
</div>
<div class="form-group">
<button type="submit" class="btn btn-primary">Submit</button>
</form>
On the home page, the data is rendered as follows. I've had to switch the numbers around as you can see, as 2= title 1=name and 3 = comment
{% for user in user_data%}
<tr>
<th scope="row">{{user[0]}}</th>
<td>{{user[2]}}</td>
<td>{{user[1]}}</td>
<td>{{user[3]}}</td>
</tr>
{% endfor %}
Whether the above has anything to do with the error, I don't know (the order)...but I cannot think why.
Finally, here is the table populate .py file. You'll notice there is one extra field - date. Again, could this be a factor?
#populate database file
import sqlite3
db_locale='users.db'
connie=sqlite3.connect(db_locale)
c=connie.cursor() #use this to create commands
#creating a multi-line instruction
c.execute("""
INSERT INTO comments (name,title,comment,date_posted) VALUES
('Ruth Marvin','42','Yeah.Someone was going to say 42','20th July 2050'),
('Jonathan Peter','Meaning?','Surely we need to first define meaning','13th August 2050')
""")
connie.commit()
connie.close()
Can anyone explain why the data is not being POSTED/INSERTED into the database.

Answer 1

The error is in the function insertcomment(). You are missing the brackets with commit:
connie.commit
Just change to:
connie.commit()
which will save the changes to the database. Everything else looks fine including the database query. You are right in using a parameterised query.

Answer 2

sql_insert_string="INSERT INTO comments (title, name, comment) VALUES (%s,%s,%s)"
c.execute(sql_insert_string, user_details)
connie.commit()
this should work. Wrap your db operations into a try, except block to figure out whats wrong with your queries.
try:
sql_insert_string="INSERT INTO comments (title, name, comment) VALUES (%s,%s,%s)"
c.execute(sql_insert_string, user_details)
connie.commit()
except Exception as e:
print(e)

Answer 3

You need to format your SQL insertion string using Python's format() function from the standard library.
Your code:
sql_insert_string='INSERT INTO comments (title, name, comment) VALUES (?,?,?)';
Should be like this:
sql_insert_string='INSERT INTO comments (title, name, comment) VALUES ({}, {}, {})'.format(user_details[0], user_details[1], user_details[2])
Then on your c.execute line just pass sql_insert_string as a parameter. Also, I've found that the flask-sqlalchemy module saves countless headaches, but kudos to you for taking the time to learn SQL and coding it like this.