I would like to know if it is possibe or avaliable the stackexchange sites database model.
If yes, where could I get it?
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Sign up to join this communityYou can get the schema for the data dump and SEDE in this Meta Stack Exchange post.
The architecture of the production database is not available to non-corporate customers (if it's available at all). But, you can grab one of the public domain Stack Exchange clones; their schema is no-doubt similar.