Quite late for the party, but while researching this subject again, I bumped into this topic and will recommend a pretty nice library for Rails projects: github.com/IFTTT/polo
This IFTTT lib helps to "travel through your database and creates sample snapshots so you can work with real world data in development."
It has obfuscation and can handle associations (manually / automatically) as it'll output a SQL for you to use on any environment without having production data.
Also, found this awesome tool for PostgreSQL: github.com/mla/pg_sample
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