Back in the office they will want their changes to be incorporated into the master database. Imagine you want to store some pieces of information in the most general way possible. You set up some containers to hold the information. In front of you, imagine you can see a number of these buckets. Into the first bucket you throw some pieces of information.
Some more pieces go into the second bucket and so on.
That's about as general as you can get. Now you have a problem. To retrieve the information from one of your buckets you need to be able to identify the bucket. You could use one of the pieces of information that you put in the bucket. For example, a person's name or phone number.