mySql help

i have a db where i want to take informatioin from.
here is the structure of the table
id | page | text

1 | index | welcome
2 | page | texte page
and so on.
when some one click on a link i want to go to this table and take the corresponding text.
for the moment here is what i am doing

$result = mysql_query(“SELECT * FROM contenu”);
while($row = mysql_fetch_array($result))
{
if($row[‘page’] == $contenu)
// $contenu is the variable that has the name of the page to display
{
echo $row[‘texte’];
}
}
My concern is that if there is a lot of text and more page then i will have to take all the content. I know that there is a way that i can just get information i want without reading the whole table. Can anyone help me with that?

The other thing is when someone click on a link, there is a paramater passed through the web url display, i used $_REQUEST to get that parameter. Is it the right way to do it or there is even better?