database - Python sqlite3.OperationalError: no such table:

39
votes

I am trying to store data about pupils at a school. I've done a few tables before, such as one for passwords and Teachers which I will later bring together in one program.

I have pretty much copied the create table function from one of these and changed the values to for the Pupil's information. It works fine on the other programs but I keep getting:

sqlite3.OperationalError: no such table: PupilPremiumTable

when I try to add a pupil to the table, it occurs on the line:

cursor.execute("select MAX(RecordID) from PupilPremiumTable")

I look in the folder and there is a file called PupilPremiumTable.db and the table has already been created before, so I don't know why it isn't working.

Here is some of my code, if you need more feel free to tell me so, as I said it worked before so I have no clue why it isn't working or even what isn't working:

with sqlite3.connect("PupilPremiumTable.db") as db:
    cursor = db.cursor()
    cursor.execute("select MAX(RecordID) from PupilPremiumTable")
    Value = cursor.fetchone()
    Value = str('.'.join(str(x) for x in Value))
    if Value == "None":
        Value = int(0)
    else:
        Value = int('.'.join(str(x) for x in Value))
    if Value == 'None,':
        Value = 0
    TeacherID = Value + 1
    print("This RecordID is: ",RecordID)
4
pythondatabasesqlite
Have you created the table PupilPremiumTable or not ? - Bhargav Rao♦
Yes the table has already been created before, sorry if this was not clear. It is in the same folder as this python file. - Ben
Note that if you have a file called PupilPremiumTable.db it doesn't mean that you have a table called PupilPremiumTable - Bhargav Rao♦
I've tried connecting to both PupilPremiumTable and PupilPremiumTable.db. When I changed line: with sqlite3.connect("PupilPremiumTable.db") as db: to with sqlite3.connect("PupilPremiumTable") as db: It didn't throw up an error, but still got stuck in the same place, and the same thing when I changed cursor.execute("select MAX(RecordID) from PupilPremiumTable") to cursor.execute("select MAX(RecordID) from PupilPremiumTable.db") - Ben
@BhargavRao: the table exists, the database exists, but by using a relative path you open it in the current working directory. The current working directory can be anything, and depends on how the script was started. - Martijn Pieters♦

4 Answers

72
votes

You are assuming that the current working directory is the same as the directory your script lives in. It is not an assumption you can make. Your script is opening a new database in a different directory, one that is empty.

Use an absolute path for your database file. You can base it on the absolute path of your script:

import os.path

BASE_DIR = os.path.dirname(os.path.abspath(__file__))
db_path = os.path.join(BASE_DIR, "PupilPremiumTable.db")
with sqlite3.connect(db_path) as db:

You can verify what the current working directory is with os.getcwd() if you want to figure out where instead you are opening the new database file; you probably want to clean up the extra file you created there.

2
votes

I had the same problem and here's how I solved it.

  1. I killed the server by pressing Ctrl+C
  2. I deleted the pychache folder. You'll find this folder in your project folder.
  3. I deleted the sqlite db.
  4. I made migrations with python manage.py makemigrations <app_name> where <app_name> is the specific app that contains the model that's causing the error. In my case it was the mail app so I ran python manage.py makemigrations app.
  5. I migrated in the normal way.
  6. Then I started the server and it was all solved.

I believe the issue is as Jorge Cardenas said:

Maybe you are loading views or queries to database but you haven´t granted enough time for Django to migrate the models to DB. That's why the "table doesn't exist".

This solution is based on this youtube video

0
votes

I have to face same issue and there are a couple of approaches, but the one I think is the most probable one.

Maybe you are loading views or queries to database but you haven´t granted enough time for Django to migrate the models to DB. That's why the "table doesn't exist".

Make sure you use this sort of initialization in you view's code:

form RegisterForm(forms.Form):

    def __init__(self, *args, **kwargs):
        super(RegisterForm, self).__init__(*args, **kwargs)

A second approach is you clean previous migrations, delete the database and start over the migration process.

0
votes

First you need to check if that table is 100% exist in the datbase you can use sqlite viewer for that https://inloop.github.io/sqlite-viewer/

if table exist then you can write your table name in '' for example

''' Select * from 'TableName' '''

what ever your query is I am just using Select * as an example