Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Welcome To Ask or Share your Answers For Others

Categories

0 votes
1.2k views
in Technique[技术] by (71.8m points)

sqlite - Auto Increment on Composite Primary Key - Sqlite3 + Python

I have a code like this

c.execute('CREATE TABLE IF NOT EXISTS base (ID INTEGER NOT NULL, col2 TEXT NOT NULL, col3 INTEGER, PRIMARY KEY(ID, col2))')

This code gives me an sqlite3.IntegrityError exception even though I am very sure that I am writing the record for the first time.

So, I tried

c.execute('CREATE TABLE IF NOT EXISTS base (ID INTEGER, col2 TEXT, col3 INTEGER, PRIMARY KEY(ID, col2))')

This inserts the row fine in the base table BUT, ID column is not auto incremented at all.

What can I do? Any idea?

See Question&Answers more detail:os

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome To Ask or Share your Answers For Others

1 Reply

0 votes
by (71.8m points)

In sqlite, you only get autoincrement behavior when only one integer column is the primary key. composite keys prevent autoincrement from taking effect.

You can get a similar result by defining id as the only primary key, but then adding an additional unique constraint on id, col3.

If that's still not quite what you want (say, id's don't need to be unique at all), you probably will have to use a trigger to make autoincrement work.


与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
OGeek|极客中国-欢迎来到极客的世界,一个免费开放的程序员编程交流平台!开放,进步,分享!让技术改变生活,让极客改变未来! Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Click Here to Ask a Question

...