在客户端为2层应用程序公开数据库连接字符串有哪些安全问题

Recently I am doing an investigation for creating a multiple tier application. Every topic that I have read suggests that the 3-tier architecture is better than the 2-tier architecture because by exposing the connection string of the database at the client side you create a big security hole at your system. All of these articles just explains that it is a bad idea to expose the location of the database and none of them explains why. Recently I am doing an investigation for creati