You table structure would be:
AgeCategory
ID(PK) -- Category<br />
1 -- Young<br />
2 -- Adult<br />
3 -- Old
User
ID(PK) -- Name -- AgeCategoryId(FK to the AgeCategory)<br />
1 -- ABC -- 1<br />
2 -- WER -- 2<br />
3 -- RTY -- 2<br />
4 -- FGH -- 1<br />
5 -- SDF -- 3
And you haven't specified which technology are you using for inserting the data from the HTML to DB, we can't really help on that. But the pseudo code would be,
if(txtage < 18)<br />
else if(txtage >= 18 && txtage <= 60)<br />
else<br />
<br />
-KR