Sign Up to our social questions and Answers Engine to ask questions, answer people’s questions, and connect with other people.
Login to our social questions & Answers Engine to ask questions answer people’s questions & connect with other people.
Lost your password? Please enter your email address. You will receive a link and will create a new password via email.
Please briefly explain why you feel this question should be reported.
Please briefly explain why you feel this answer should be reported.
Please briefly explain why you feel this user should be reported.
I am using the following syntax to insert new records (I don’t want to have duplicate keys):
insert into tbl(key) values select max(key)+1 from tbl
Someone says it will have concurrency problem.
Is that right?
SELECT -> LOCK table -> INSERT
or
LOCK table -> SELECT -> INSERT
Which one of the above is correct?
The select will lock the table, and you are doing everything in a single statement, looks like you should be fine (other than maybe performance to calculate the max(key)).