How can we handle DB Transactions?

[yasalkhatib]

I have a question regarding DB Transactions.

Example

Money Transfer from account A to Account B.
Feature: TranserMoneyFeature
Jobs:
1. Withdraw Money from Account A
2. Deposit money in Account B

What I would want to achieve is to make the two jobs above as a unit. All jobs or none.

Would you please suggest a way to do that?

[Mulkave]

If i understand correctly you're looking into a reversal in case one of these jobs fail? If so, this is an interesting case!

This makes a good case for an operation.

Important
Before going into the details, I'd like to highlight that these are usually handled at the DB layer and not at the architecture layer, where you would create a DB transaction which will revert itself when things don't go as planned.

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However, if you were to do it manually at the architecture level, here's one suggestion to make it happen:

• TransferMoneyOperation($fromAccount, $toAccount) -> returns TransferStatus object summarising the jobs' results
  • WithdrawMoneyFromAccountJob($fromAccount, $amount)
  • DepositMoneyInAccountJob($toAccount, $amount)

Based on the result from the TransferStatus which could hold as many details as required about the failure if it were to happen, the next operation can take place.

If failed run RevertMoneyTransferOperation($transferStatus, $fromAccount, $toAccount, $amount) which contains two jobs that run conditionally.

• If withdrawal error: RevertMoneyWithdrawalFromAccountJob($fromAccount, $amount)
• If deposit error: HandleDepositErrorJob($fromAccount, $toAccount, $amount)

The reason why the second job isn't named with the same convention (revert etc.) is because it contains more work than

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General Suggestions

• Build rich Jobs: Jobs don't need to be shallow (performing single-line jobs or contain simple code) but rather should be deep/rich in order to provide reusability
• Use objects as an exchange structure: Exchanging objects between components ensures the robustness of the application. For example:

TransferMoneyOperation(Account $fromAccount, Account $toAccount)
WithdrawMoneyFromAccountJob(Account $fromAccount, [float|int] $amount)

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Please let me know your thoughts on the above @yasalkhatib