Don't want to create a new database if it doesn't already exists

Question

If I have the following code:

conn = sqlite3.connect('abc.db')

.. it will create DB fle called abc.db if it doesn't already exist. What do I do if I don't want to create a new file and only want the connection to succeed if the file already exists?

Check if the file 'abc.db' exists before creating the connection object : `os.path.isfile('abc.db')` — michaelmeyer, Jun 18 '13 at 13:33
Duplicate of https://stackoverflow.com/questions/12932607/how-to-check-if-a-sqlite3-database-exists-in-python. — Jurko Gospodnetić, Nov 17 '17 at 13:31
Possible duplicate of [How to check if a SQLite3 database exists in Python?](https://stackoverflow.com/questions/12932607/how-to-check-if-a-sqlite3-database-exists-in-python) — Jurko Gospodnetić, Nov 17 '17 at 13:32

score 5 · Answer 1 · answered Jun 18 '13 at 13:33

5

Use sqlite3_open_v2() with either SQLITE_OPEN_READONLY or SQLITE_OPEN_READWRITE.

As described here: http://www.sqlite.org/c3ref/open.html

answered Jun 18 '13 at 13:33

Vicky

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How do you do that in Python? – Eugene Gill Jun 18 '13 at 13:38
2

Actually this answer is on the right track. It is possible to call the **sqlite_open_v2()** API from Python, albeit indirectly, by using an URI style database identifier passed to **sqlite3.connect()**. For more gory details see https://stackoverflow.com/a/47351716/4231304. – Jurko Gospodnetić Nov 17 '17 at 13:29

score 4 · Accepted Answer · answered Jun 18 '13 at 13:33

4

You can check if the file already exists or not:

import os
if not os.path.exists('abc.db'):
    conn = sqlite3.connect('abc.db')

answered Jun 18 '13 at 13:33

Ashwini Chaudhary

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@EugeneGill http://stackoverflow.com/questions/10205744/opening-sqlite3-database-from-python-in-read-only-mode – Ashwini Chaudhary Jun 18 '13 at 13:39
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This solution has a race condition. – Nayuki Nov 22 '18 at 02:06

tenstar · Answer 3 · 2013-06-18T13:49:50.493

-2

you can chill, python doesn't create a new database if it is already existing and connects to the pre-existing one!

works in python 2.7 !

try this:

import os
if not os.path.exists('path/to/database'):
    conn = sqlite3.connect('abc.db')
else:
    print "Error! db already exists!"

edited Jun 18 '13 at 13:49

answered Jun 18 '13 at 13:42

tenstar

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That wasn't the issue. I didn't want to connect to a non-existent database, which causes a new DB to be created, if didn't already exist. – Eugene Gill Jun 18 '13 at 13:46

Don't want to create a new database if it doesn't already exists

3 Answers3