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Implementing auto increment programitcally

 
Satyajeet Kadam
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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
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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.
 
Satyajeet Kadam
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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

tcount===2


databse value
104
 
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