Tags list in stackoverflow

I am working on website in asp.net mvc. There is form where user is asked to put some information along with the Tags similar to stackoverflow. this tags information is saved in the same table in field Tags.

Now I want to show them a help to select tags from the list开发者_如何转开发 (same as in stackoverflow). how can i extract it from the table. Wont it be too much to run the query again and again for each letter they type, because I will be extracting unique tags from my table. Or should i have another table tagslookup where i should save unique tags.

Help will be appreciated.

Regards

Parminder

When we had to do something like this, we stored the "tags" (words) in memory and created a search tree.

Wont it be too much to run the query again and again for each letter they type, because I will be extracting unique tags from my table.

This really varies on a case by case basis. Personally, I wouldn't go to the db each time, but it may be fine for your scenario.