I have to write an app for iPad that would take data from SQL Server and post it to the iPad. I looked up on this over the Internet and found that I have to write a web service to expose the data from SQL server using ASP.NET. I did an app previously in android that would take data from my dropbox a/c and display it to the user. I made use of the drop-box API available. I was wondering if anything like that exists for SQL? Also, I have to code in Obj-C for the iPad, so how will I write ASP.NET code? I have more doubts.
Use OData. See Creating an OData API for StackOverflow including XML and JSON in 30 minutes for how to publish your SQL Server data as an OData service. See Consuming OData using Objective-C for how to consume the OData service from your iPhone app.