 of each procedural language explains how to write a
    trigger in that language.
   </P
><P
>    Trigger functions must use the <SPAN
CLASS="QUOTE"
>"version 1"</SPAN
> function manager
    interface.
   </P
><P
>    When a function is called by the trigger manager, it is not passed
    any normal arguments, but it is passed a <SPAN
CLASS="QUOTE"
>"context"</SPAN
>
    pointer pointing to a <TT
CLASS="STRUCTNAME"
>TriggerData</TT
> structure.  C
    functions can check whether they were called from the tr