Reverse Snowflake Joins

revj.sourceforge.net

34 points·thunderbong··6 comments

Laughed at "Big SQL" can be as many as 20 tables, joined by multiple fields" - stares in 17 thousand LOC dynamic sql.

Yeah, having seen the monstrosities Tableau generates, that example seemed quaint.

I don't do much SQL work, but I can recall a couple times in the past when this could have been handy. However, the last release appears to be v0.49 (2011-12-06).

https://sourceforge.net/projects/revj/files/revj/

Right. And it targets python 2.x. And ... I don't see a Source tab on the sourceforge page?

That said... Shut up and take my money. The second example on http://revj.sourceforge.net/example.html matches recurring problems I have at $work so perfectly that I simply must use this tool--or something like it.

...How does it pick the center table?! How would I pick the center table, if I were drawing a diagram like this by hand? Maybe I don't need to use the tool, and only need to internalize the operative concepts. The tool documentation links to this: https://en.wikipedia.org/wiki/Snowflake_schema Hm.

There's lots of python libraries for graph visualization, it's probably force-directed layout or something else similar.

The name is indeed a reference to data warehouse design, where you normally have heavily normalized data in a snowflake schema. The Kimball book is the canonical one on data warehouse design.

Yep. This app, revj, uses Graphviz for layout. So, sure, force-directed layout.

The layout/rendering of the graphs isn't interesting to me, but parsing a SQL statement and extracting the relationship data is.

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