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Implementing auto increment programitcally

Satyajeet Kadam
Ranch Hand

Joined: Oct 19, 2006
Posts: 224
I using mysql databse, i am implementing auto increament field programitically. Find the no of records in table and incrementing it by 1.
I want to this for "user_id field"

Each time when user adds a new record it will programtically increment user_id by 1 to no of records currently present in ts_user table

I am getting error when i excute query:

Scott Selikoff
Saloon Keeper

Joined: Oct 23, 2005
Posts: 3753

You should use an alias such as "select count(*) as the_sum ..." then you can call getInt("the_sum") to read it. In particular though, selecting count is a *really* bad practice for auto-incrementing data. First and foremost, if an old record is deleted, the entire system stops being able to insert records. Selecting the max id + 1 is generally better, but keep in mind none of these techniques are thread safe if you don't wrap them in a transaction. Two users both trying to insert records could collide if they both read the same id.

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Satyajeet Kadam
Ranch Hand

Joined: Oct 19, 2006
Posts: 224
Thanks for your solution, it incrementing value by 1 but databse is getting upddated with different value.

Q How to implement transactions in follwoing code?

Tomcat console


databse value
I agree. Here's the link:
subject: Implementing auto increment programitcally
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