Updates a single cell row that matches the key values supplied.
You cannot change the values of keys cells in a space object. To alter the values of key cells you must delete and (re)insert the cell row.
The field values must be specified in the same order as the cells in the space were defined. Cells are matched by the order of their specification in arguments 2 -> 20. The names of the fields used have no bearing whatsoever on the cell mapping logic.
If you specify less field values than there are cells in the space then the non-specified cells are set to blank/zero/null values as appropriate.
If you specify more field values than there are cells in the space then the additional field values are ignored.
If a key value longer than 256 bytes is specified, a fatal error will occur.