Python SQLITE3 插入和冲突时更新变量 - 语法问题？

Question

I am running this code in a method that is called in a for loop and passing to it 'text_body':

*connecting to db*

cursor.execute('CREATE TABLE IF NOT EXISTS temp_data (temp_text_body text, id integer)')

cursor.execute('INSERT INTO temp_data(temp_text_body, id) VALUES (?, 1) ON CONFLICT (id) DO UPDATE '
               'SET temp_text_body = temp_text_body || (?)', (text_body, text_body))

*commiting connection*

My goal is to, on first time this is called to create a table and fill it with 'text_body', then on a second call add to the first 'text_body' second 'text_body' and so on.

I tried many combinations of this code, I was also trying to do it with UPDATE (and it was fine but UPDATE needs some data to actually start working).

When my code comes to this places it's just stop running, no error no anything. Could some please let me know where I made a mistake?

Answer 1

You cannot set 'ON CONFLICT' on a field which is not a primary key or which does not have a 'unique constraint'. Here's the error message I get when running your code:

sqlite3.OperationalError: 
ON CONFLICT clause does not match any PRIMARY KEY or UNIQUE constraint

This in essence is because you cannot have a conflict if there is no Primary Key/ Unique constraint on that field.

Under the assumption that you want id to be a unique Primary Key, I've created a working snippet:

import sqlite3

cursor = sqlite3.connect('stack_test.db')

cursor.execute('''CREATE TABLE IF NOT EXISTS temp_data 
                    (temp_text_body TEXT, 
                    id INTEGER PRIMARY KEY)''')

cursor.execute('''
                    INSERT INTO 
                        temp_data(temp_text_body, id) 
                    VALUES 
                        (?, 1) 
                    ON CONFLICT (id) DO UPDATE
                    SET 
                        temp_text_body = temp_text_body || (?)''',
            ("foo", "bar"))

cursor.commit()

I've also made some stylistic changes to how you write your query statements which I hope will made them a little easier for you to debug!

Best of luck with the SQLite'ing, feel free to ask if any part of my answer is unclear:)