Hello,

First time poster, new to C# so looking for a bit guidance from those that know more than I do! 

This involves SharePoint 2013, SQL Server 2012, and a Web Service, so had a bit trouble choosing a category.
 
I have created a form with InfoPath 2010, it was a blank form, with various drop down boxes etc.. What I would like to do it is publish it into SharePoint 2013, and users will fill in the form and hit submit, the data (not the form) will then go into a SQL Database table.
The users also need to be able to retrieve the form, and if necessary, make changes and resubmit. Now in InfoPath its easy to have a form retrieve or submit, but to be able to do both and resubmit, I need to specify a Web Service. Until yesterday, I knew nothing about Web Services, so from what I understand I need to create one in Visual Studio using C#.
 
I have Visual Studio Community downloaded (other versions of VS are available to me), I need some guidance on creating a web service to submit and retrieve data to and from the database via the form, but also how it all fits together, and whether I am missing something.
 
For example once the database is in place and I have published the form, how does the web service bridge the gap?
If I add the web service to the form, does it follow the form up into SharePoint when I publish it? 
 
If you need any more details to help me out, then I am more than happy to supply them.
 
Thank you in advance for any help given.
 
Kind regards,
P.