* at one time; if a value is not available to be edited then [edit] will return null.
 *
 *  * When an entry is being **created** it is necessary to supply a full set of values; the empty
 *    value should be used as a placeholder if necessary.
 *
 *  * When an entry is being **edited**, it is not necessary to supply data for every value; values
 *    default to their previous value.
 *