Will Installation of Service Pack 3 on SQL Server 2012 Web Edition (existing production) require database restore activity? We are currently running our Database Server on a RTM version:

Microsoft SQL Server 2012 - 11.0.2100.60 (X64) 
    Feb 10 2012 19:39:15 
    Copyright (c) Microsoft Corporation
    Standard Edition (64-bit) on Windows NT 6.2  (Build 9200: ) (Hypervisor)

We learnt that we need to install the latest Service Pack for SQL Server 2012, which is SP3

I had the following doubts based on this subject:


Will installation of SQL Server 2012 Web Edition SP3 affect any of our production databases?
Do we need to restore the databases, after installation of SP3?
Are there any particular prerequisites we need to follow before the installation of SP3?
Do we need to perform a database backup and backup of the data files before the installation of SP3?


Please advise. Appreciate your help on this. Thanks.
Installing service packs usually goes like this: detailed step by step guide


It shouldn't affect databases, but you may want to test installing SP3 on the test server first. It will help you get an idea how long it takes (management will want to know that beforehand). It will also give you a chance to find out if any of your applications (or anything else) got affected. Safety always comes first so production is never the best place to patch first. 
No, you don't need to restore anything. Existing databses will be in the same state as they were before the installation. Settings (collation etc) will remail unchanged as well.
You may want to read about bugs in SP3 and potential problems that can occur during instalation. There is plenty of examples on Google. You may also want to kave a look at the release notes to understand better what fixes are contained in SP3.
I always do (just in case), but you don't have to. It is really about how concerned your managers are about data integrity, safety etc. It is usually recommended to backup all databases before any maintenance.