import recreates proliferates same check constraints

Back 5 days before Sept 11, 2001 dan_at_nospam.com initiated a thread (Subject: ccol$) in which Jonathan Lewis (3rd message) observed that when you refresh data by truncating tables and re-importing, Oracle will not recognize the existence of equal check constraints and will re-create the check constraint all over again. Here is an excerpt from his message:

“If you keep refreshing data by truncating and importing,
then some classes of constraints that you have defined will be re-created each time you do the import.”

My question is: Why does Oracle allow its Import utility to behave in this manner? Is this considered a known bug that Oracle may remedy in a future release? Does anyone have a recommended tested approach to refreshing data and objects and at the same time avoiding this proliferation of the same check constraints ?

The proliferating check constraint phenomenon was also noted in a thread initiated by Stan Brown (stanb_at_panix.com Subject: Confused about "check" style constraunts Date: 2001-08-21 06:54:45 PST):
“So, it appears that soehow (perhaps export/import ?) I have
created many extra constraints on some of my tables (I was able to replicate the probelm on a different table). So, any sugestions as to how to clean this mess up?” The thread became frozen before anyone responded to his question.

Thanks in advance for your help !

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David Heitholt
Agency.com