There's a bit of a killer tool that's relatively well known in geospatial data circles (and has been kicking about for a few decades) called FME from Safe Software [1] that I've never seen referenced in the non spatial database circles.
It's got some of the best table visualisation and table/tool/translation/QC intergration visual design tools I've seen.
It's essentially built with the goal of starting with multiple table sources in various ASCII / <some>SQLDB format and displaying all tables, building filter pipes to merge and translate data on the fly and produce single or multiple coherent databases and table sets (or even more ascii tables) as output.
It has it's quirks but it's a solid bit of kit ( I used it some years back to read in and unify data from several million leases (geospatial boundaries and related metadata) from multiple sources (Australian, Canadian, South African, etc. land departments) - from whoa to go was about four days, once running it chewed through the data on par with normal copy speeds (eg: it imported cleaned & filtered data in a time ballpark to just copying the data from A->B).
I'm not affiliated, but on the basis of that job, yeah, I'll spruik it.
[1] http://www.safe.com/
[2] http://www.safe.com/fme/fme-technology/fme-desktop/overview/
( See desktop demo video from overview section )