I&#39;m looking for recommendations of a good, free tool for generating sample data for the purpose of loading into test databases.  By analogy, something that produces &quot;[lorem ipsum][1]&quot; text for any RDBMS.  Features I&#39;m looking for include:

 - Flexibility to generate data for an existing table definition.
 - Ability to generate small and large data sets (&gt; 1 million rows or more).
 - Generate in SQL script format (`INSERT` statements) or else in a flat file format suitable for bulk import (which is usually faster).
 - A command-line interface for easy scripting.
 - Extensible, open source, written in a dynamic language (these are nice-to-haves, not strong requirements).

PS: I did search for a duplicate question on StackOverflow, but I didn&#39;t find one.  If there is one, I&#39;ll be grateful to get a pointer to it.

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Thanks for the great responses everyone!  I should amend my requirements that I use Mac OS X as my primary development environment, not Windows (though I did say command-line interface is desirable, and that *practically* rules out Windows).  The Windows-specific suggestions will no doubt be useful to other readers of this question, though, so thanks.

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Here is my conclusion:

 - GenerateData: 
  - PHP web app interface, not command line
  - limited to generating 200 records (or pay $20 for license to generating 5,000 records)
 - RedGate SQL Data Generator
  - not free, price $295
  - requires Windows, .NET, SQL Server
 - Visual Studio 2008 Database Edition
  - requires Windows
  - requires costly MSDN or ISV subscription
 - Banner Datadect
  - not free, price $595
  - requires Windows (?)
  - no support for MySQL (?)
  - GUI, not command line or scriptable
 - Ruby Faker gem
  - way too slow to use ActiveRecord for bulk data load
 - Super Smack
  - chiefly a load-testing tool, with a random data generator built in
  - pretty simple to use nevertheless
  - overall a good runner-up tool
 - Databene Benerator
  - best solution for my needs
  - XML scripts, compatible with DbUnit
  - open source (GPL) Java code
  - command-line usage
  - access many databases directly via JDBC

  [1]: http://en.wikipedia.org/wiki/Lorem_ipsum

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Tools for Generating Mock Data?