It is not exactly what the OP asked for. The journaling system documents the changes, whereas the OP asked for the data that was changed.

Of course it is possible to reconstruct the previous contents by running the journal to just before the SQL that changed the data, but that would be quite cumbersome.

Of course the OP's request is also very naive, as (s)he assumes that all changes will be atomic on a single record. By simply "saving" the previous content into a history table, you are open to all kinds of race conditions, such as two connections editing different fields in the same record, which will make it dificult, if not imossible to determine what the "previous content" was.

CountZero

A program should be light and agile, its subroutines connected like a string of pearls. The spirit and intent of the program should be retained throughout. There should be neither too little or too much, neither needless loops nor useless variables, neither lack of structure nor overwhelming rigidity." - The Tao of Programming, 4.1 - Geoffrey James

In reply to Re^2: data historization with DBIx::Class by CountZero
in thread data historization with DBIx::Class by morgon

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