Outside database connection - (securely) - MySQL/PHP
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I'm developing an online application that will have many outside users. As for now my connection method is to host a centralized database for all users, while they connect from their own server files.

**Method:**<br>
*PHP Connection File (hosted on their server; file provided by me)* **>>** *Connects to my MySQL Database*

Now obviously I need to provide my database user and pw info, but I know that questions security.

So to my point, how would I provide database access to outside users(different servers) without giving up security.

Or if someone has a better method I'd love to hear it. Thanks!