can u help me...i have to do a 'knowledge and information retrieval system'..and i wanna know what is your opinion if i'm using php/mysql as my tool in order to develop the system...the system is like user enter a phrase of word then..then system will search the matching word that the user have entered..more like search engine function..it is complicated?
i really appreciate if u can share your opinion...thank u.

$lookingfor=user input
$query = "SELECT * FROM table_name WHERE text_is_store LIKE '$lookingfor'";
thats pretty simple to me.. some might not think so.

Obviously its a bit more complicated.. because if you put $lookingfor='Today' then you will get every documents with the word 'Today' returned .. so you need to do some filtering and more important you need to consider the amount of datas which are going to be stored.
1 table with 5000 data is ok.. 1 table with 500 000 .. you might get a bit of lag on the Query.

Overall, if you have some basic knowledge of programming its dead easy.