Adding a new entity type (and database table)

Hi, I'm creating a website that's very search-oriented and I'd like to have

a table strictly for restaurants, that will contain the restaurant genre, location etc.

I want to do this because restaurants have certain columns that are special for them

and I want to create a mySQL index using these columns to optimize the searches.


My questions are:

1. are there ways to this without touching the core?

2. what are the implications of this regarding elgg updates, I've never done an elgg update

and don't know how it works, does it replace all the engine php files? so in case I edit one

of them so when I update it'll erase the changes I made?


Thanx in advance and any solutions are welcome, fiftyeight.