Adding sql-mode hook

[address@hidden]

Am trying to add a sql-mode hook with

(add-hook 'sql-mode-hook 'sql-highlight-oracle-keywords)

in my .emacs but none of the oracle keywords are highlighted when I
enter SQL mode. Only invoking the sql-highlight-oracle-keywords
function seems to highlight them. What is it that I am missing? Why
don't the keywords get highlighted as soon as I open a SQL file?

Emacs version 21.3.1 on Windows 2000.

Thanks,
Krishna