How did they success to hack my database?

[mgdmgd]

How did they success to hack my database?
I used Rauno Web costs about 35$ i didn't bought it but my friend did, but how did they success to hack my database? they was able to change passwords and gradeids and etc :/
Any idea how to block it?

[MentaL]

[NubPro]

injections and exploits.

[Eronisch]

What NubPro said, you could use: http://www.acunetix.com/vulnerability-scanner to check if it finds any exploits.

This is just an indication though, but it can be pretty helpfull.