Is there an existing piece of software that allows you to (easily) build queries throught a webpage?

I would like to build arbitrary queries to a database, by allowing the user to build queries "on the fly". For every object/table, being able to select its attributes, and then "building" the query (that would translate into a SQL statement) and finally launching it, all through a web interface. The ticketing system "rt" does t开发者_JAVA百科hat, for example, and another example would be the http://gatherer.wizards.com/Pages/Advanced.aspx webpage.

I'm currently programming in rails but any existing solution that implements this (or something similar) would be welcome.

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Just be careful when creating dynamically generated queries like this that will need to be executed via sp_executesql (example: ms sql server), etc..... make sure you cover all of your bases to ensure that your application isnt vulnerable to SQL injection attacks as this type of development will essentially get one in a lot of trouble if its done incorrectly.. I would recommend storing all queries in a table and only reading queries from this table to help isolate the queries that are being ran in your application. Just identify them with a label, and allow the EU to choose the label from a dropdown list control on the frontend.

Good luck and I'm not sure of any software that will help assist

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Not quite sure what your use case is here but i would say check out the

Doctrine ORM ( Object Relational Mapper )

**Edit After reading more and looking at the example. I would only suggest Doctrine for a large website.

Then use Doctrines DQL syntax with some javascript/jquery magic for the forms.

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Note that the queries you're referencing aren't arbitrary: they're on a very specific problem domain, on a specific set of sql tables.

That said, if I were you I'd look into how people are building sql queries with javascript. Something like these:

http://code.google.com/p/django-querybuilder/

http://css.dzone.com/articles/sqlike-sql-querying-engine?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+zones%2Fria+(RIA+Zone)

http://thechangelog.com/post/4914956307/rel-arel-ported-to-node-js-with-some-changes

That'll at least get you a good idea of the underlying data structures.