python：更新现有的sqlite数据库

Question

Have a python script that creates a sqlite database:

import sqlite3

con = sqlite3.connect('some.db',detect_types=sqlite3.PARSE_DECLTYPES)
with con:
    cur = con.cursor()
    cur.execute("CREATE TABLE Title(ID INT, ...)")

and then later populates the db with content from a list:

    <ID> = <whatever>
    <var1> = <you get the point>

    altogether = (ID, var1...)
    cur.execute("INSERT INTO Title VALUES(?,?,...)", altogether)
    con.commit()

I now want to write a modified version of this script that takes an existing some.db and updates it, but only does so if the ID doesn't already exist in the database.

How do I:

1. open some.db for read/write to update values only

2. query the db to make sure that the ID of the item that I'm currently iterating through does not already exist in the db? The way that I'm currently populating variables is by making API calls to an external service that I'd like to be able to skip if the entry is already in my db.

Answer 1

1. Same way you already did.

2. Don't. Make the column UNIQUE and handle the exception on INSERT .