Problem description: When using the postgresql JDBC driver, linking a subform to another subform appears to convert the linking parameter to a character varying datatype.  So when the filtered field is something other than text, you get an operator error when you try to filter on that linked parameter.

This isn't a problem when linking a masterform to a subform, only when linking a subform to another subform. 

Steps to reproduce:
1. Create a form based on a postgresql db table (say customer_id, customer_name)
2. Create a subform1 (level 1), linking an integer field (say customer_id, customer_orders)
3. Create a subform2 (level 2), linking the same integer field (say customer_id, order_id, item_no)

Current behavior: Between subform 1 and subform 2, customer_id is converted to a text datatype.  So by the time subform2 gets the customer_id, it's text rather than an integer, and errors out when it tries to filter.

It would appear that subform 1 is being auto-built on a query of the master form (SELECT * from orders where customer_id = link...) and this resultset is being put into some type of temp table, where all the fields are stored as text.  So when subform 2 tries to join subform 1, it errors when trying to join on an integer datatype.

Expected behavior: You would expect the data to keep the same type throughout the process.

Platform (if different from the browser): 
              
Browser: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/535.16 (KHTML, like Gecko) Chrome/18.0.1003.1 Safari/535.16