Creating an unique database column with auto-increment from a starting number in Rails 4.2.5

Question

i have a database table with this column t.integer :account_number, :limit => 9. I need this column to automatic generate on the account creation, to auto-increment by 50 for each account created and it has to start( from the first account) at value of 450230000. So i will have the account with ID = 1 and ACCOUNT_NUMBER = 450230000, account with ID = 2 and ACCOUNT_NUMBER = 450230050. I'm using Rails 4.2.5 and SQLite as database. There is a way to have this type of auto-increment column in Rails?

[this](http://stackoverflow.com/questions/692856/set-start-value-for-autoincrement-in-sqlite) seems relevant — Imran Ali, Jun 06 '16 at 10:04
Right, i just have to create the first row on my own then delete it when the count will start, thanks! — Luigi Versitelli, Jun 06 '16 at 10:13

score 2 · Accepted Answer · answered Jun 06 '16 at 10:04

2

Add callback in model before saving your object

before_create :set_account_number
def set_account_number
  last_account_number = Account.maximum(:account_number)
  self.account_number = last_account_number.to_i + 50
end

Do something like that in your model

answered Jun 06 '16 at 10:04

Sachin R

11,606
10
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Ok, it works but i need that, by default, on the first account i will create the account number has to be 450230000. It is possible? – Luigi Versitelli Jun 06 '16 at 10:07
It's is better logic...Nice @M Kumar – Mukesh Jun 06 '16 at 10:10

score 1 · Answer 2 · answered Jun 06 '16 at 10:04

1

This logic, can help you

before_create :inc_acc_num   //callback 

def inc_acc_num
  self.account_number = Account.last.try(:account_number) + 50
end

answered Jun 06 '16 at 10:04

Mukesh

921
10
23

Creating an unique database column with auto-increment from a starting number in Rails 4.2.5

2 Answers2