in a secondary control file override the
     primary control file when installing or updating to that version of
     the extension.  However, the parameters <TT
CLASS="VARNAME"
>directory</TT
> and
     <TT
CLASS="VARNAME"
>default_version</TT
> cannot be set in a secondary control file.
    </P
><P
>     An extension's <ACRONYM
CLASS="ACRONYM"
>SQL</ACRONYM
> script files can contain any SQL commands,
     except for transaction control commands (<TT
CLASS="COMMAND"
>BEGIN</TT
>,
     <TT
CLASS="COMMAND"