使用 python 和 sqlite3 检查用户名是否在数据库中

Question

I'm trying to check if a username is in a database using python and SQLite3, here's my code

name = request.form.get("username")
namecheck = db.execute("SELECT * FROM users WHERE username=?", (name))
if name in namecheck:
    return apology("Username already exists")

Sorry, I'm still pretty new to this, why isn't this working?

Answer 1

The pattern you are using is wrong here. Most typically you should be calling db.execute() as a void function. Then, you should be iterating the db object to get the records. That being said, I would use an exists query here:

name = request.form.get("username")
sql = 'SELECT EXISTS (SELECT 1 FROM users WHERE username = ?)'
db.execute(sql, (name,))
if db.fetchone()[0]:
    return apology("Username already exists")