What is the difference between validation and substitution in SAP?

Answer»

VALIDATION	Substitution
Here you can quickly CHECK the FIELD contents of the validating documents and prevent the POSTING of any MATERIAL via an error message.	Here you can easily overwrite any field documents of the accounting document which have been posted if there any changes/updates to it.
In this, the validation function is used for checking the entered values and value intervals.	Here the values are checked using prerequisites defined by the user.

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