This question gets asked at different times: certainly, during a proof-of-concept, sometimes during an assessment and almost always just before going live, when everything is being checked and double-checked.
Often, the following informal formulation is being used:
Meaning two different things:
In order to vouch this, Anubex has embedded a data verification mechanism into their data migration solutions. Together with the batch and online application testing cycles, one can sleep on both ears when no differences are detected.
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