Skip to content

Finish Safely

This lesson removes what the tutorial created: the tutorial table and, if you used it, the Docker lab. It also tells you how to recover when a lesson was interrupted or run twice. It follows Commit and Roll Back.

Before you start

You need the same folder, the same five connection values and an active virtual environment (in a new terminal, run source .venv/bin/activate again). You can run this lesson at any point after Save a Row and Read It Back, also when a lesson failed half way.

Clean up the tutorial table

cleanup_quickstart.py removes the tutorial table, and only if the table of that name owned by your user carries the tutorial's comment. A table of the same name that you created yourself, or one that belongs to another user, is left alone. Create it in the same folder, with the same SETTINGS:

import pycubrid

SETTINGS = {"host": "localhost", "port": 33000, "database": "testdb", "user": "dba", "password": ""}
MARK = "created by the pycubrid quickstart"

conn = pycubrid.connect(**SETTINGS)
cur = conn.cursor()
cur.execute(
    "SELECT comment FROM db_class WHERE class_name = ? AND owner_name = CURRENT_USER",
    ("pycubrid_quickstart_notes",),
)
row = cur.fetchone()
if row is None:
    print("Nothing to clean up: pycubrid_quickstart_notes does not exist.")
elif row[0] != MARK:
    print("Not dropped: pycubrid_quickstart_notes was not created by this quickstart.")
else:
    cur.execute("DROP TABLE pycubrid_quickstart_notes")
    conn.commit()
    print("Dropped pycubrid_quickstart_notes.")
cur.close()
conn.close()

Run it:

python cleanup_quickstart.py

It prints one of three lines:

Output What it means
Dropped pycubrid_quickstart_notes. The tutorial table was removed.
Nothing to clean up: pycubrid_quickstart_notes does not exist. Your user has no table of that name; nothing was changed.
Not dropped: pycubrid_quickstart_notes was not created by this quickstart. Your user has a table of that name without the tutorial's comment. It is left alone.

How the check works

db_class is the CUBRID catalog of tables. The query looks for a table with the tutorial's name whose owner is CURRENT_USER, the user you connected as, and reads its comment. The script drops the table only when the comment is the one that Save a Row and Read It Back wrote. The table name is passed with a ? placeholder, like any other value.

If you see Not dropped, the table is not the tutorial's: do not drop it to make the lessons work. Use another practice database or account instead, or ask whoever created that table.

Remove the Docker lab

If you used the disposable Docker lab from Option B, remove the whole container, with its database:

docker rm -f -v pycubrid-quickstart

This removes only the container named pycubrid-quickstart. The -v also deletes the container's anonymous Docker volume, which holds testdb. Without -v, the container goes but its volume stays behind on your computer (you would still see it in docker volume ls). Skip this step with your own database.

If a lesson was interrupted or run twice

What you see What to do
first_saved_row.py stops with Class dba.pycubrid_quickstart_notes already exists (with your user name) The table from an earlier run is still there. Run cleanup_quickstart.py, then run first_saved_row.py again.
first_rollback.py was interrupted before it printed After rollback Nothing to clean up: the uncommitted row is discarded when the connection ends. Run it again.
first_rollback.py stops with Unknown class "dba.pycubrid_quickstart_notes" (with your user name) Run first_saved_row.py from Save a Row and Read It Back first.

Next step

You have finished the lessons. From here: