允许Android用户访问我的数据库是一个好习惯吗？

I am using my own computer as database server and for a simple example; i want to save users registeration informations and check these informations while a user logging in. I am using apache,php and mysql. In order to check users informations I allowed all ip addresses to access my database server. I think this is obviously wrong. What is the true way to accomplish my goal? Which tools should I use?I am using my own computer as database server a