Sets the size of a page in SQL help.

    The following notes apply to the PAGE LENGTH (or PAGESIZE)
    clause:

    o  The integer value must be a value between 10 and 32767.

    o  SET PAGE LENGTH (or SET PAGESIZE) can be used to effectively
       disable the paging performed by help by setting the length to
       a high value such as 32000.

    o  The page length is automatically set upon entry to interactive
       SQL and is based on the OpenVMS terminal setting for this
       session.

    o  The SHOW DISPLAY command can be used to view the currently
       defined page length.