Difference between table.update and table.modifiedField

Question

I'm curious what the difference is between overriding a table's modifiedField method versus overriding the update method.

In our case, we are working on switching the field datatype on a table. Since we cannot just change the data type of the field, we make a second field, and copy the information from the first into the second. Eventually, we update all the UI elements (forms and reports namely) to point to the new field, and then remove the old field. To help with copying the information from one field to another, we have been overriding the update method on the table to copy the value from the first field to the second.

I know this would probably be easier to maintain using the modifiedField method, but I'm curious if there are any significant differences (performance, missed updates, etc) by using the update method instead.

Answer 1

The main difference is that the code in modifiedField method is executed without writing into the Database. This way you can change the value of field2, but if a user close the form without saving the record then no updates will be in the DB. While using an update method you certainly write the changes.