IBM's DB2
 

Hey IBMs DB2 is the most efficient Database management system and I will post for this. If you have any queries regarding this you can ask here.
Here are some links:
https://w3.tap.ibm.com/w3ki2/display.../DB2+on+Campus
http://www-01.ibm.com/software/data/.../students.html
Download DB2 Express C for free http://www-01.ibm.com/software/data/...&S_TACT=RFC001