
    sl_avail   integer,       -- available number of pairs
    sl_color   text,          -- shoelace color
    sl_len     real,          -- shoelace length
    sl_unit    text           -- length unit
);

CREATE TABLE unit (
    un_name    text,          -- primary key
    un_fact    real           -- factor to transform to cm
);</PRE
><P>

    As you can see, they represent shoe-store data.</P
><P
>    The views are created as:

</P><PRE
CLASS="PROGRAMLISTING"
>CREATE VIEW shoe AS
    SELECT sh.shoename,
