InfoPath Dev

I'm trying to understand what the web service template is doing behind the scenes - any answers appreciated: 

Is the option "Receive and submit data" simply a shortcut for first creating a receive data connection then creating a submit connection?

Why can't I start from a blank form and acheive the same thing?  If I start from a blank form and add a receive data from web service connection, then it becomes a secondary data source rather than the main one. When I add a button, I don't see the Run Query option.  And if I drag my query field to the surface I can't change it to a dropdown list like I can on the web service template.

I assume the d prefix on a database connection is for database, but why the prefix tns for the webservice namespace ?

 Thanks in advance

Binding to a Web Service creates a schema reference in your manifest and adds an XSD file to your form's XSN package.

InfoPath automatically constructs the XSD based on the parameters in the Web Service.

Secondary data sources don't have the same high bar for validation that the main data source has. That makes them faster, but you lose some functionality (master-detail, etc.)

You can Query a Receive Web Service and Submit to a Submit Web Service.

Double click the button you add. Add a rule with an action to query a data source and choose your data connection.

Thanks for that - one more: 

Why is the Run Query button different from the "normal" button?  The former has a built-in action called Run Query (and only seems available when using the webservice template), while with the latter I need to set a rule to call that action.  Seems strange having the 2 different button types.