Before the search takes place, the values of all indexes should be set for higher dimensions of the table to define a specific table of identifier-1 elements.
Identifier-1 must refer to all occurrences within the table element; that is, it must not be subscripted or indexed.
Identifier-1 cannot be a pointer data item or a procedure-pointer data item.
Identifier-1 cannot be a floating-point data item.
Identifier-1 can be a DBCS data item if the ASCENDING/DESCENDING KEY is defined as a DBCS data item.
Identifier-1 can be a date-time data item if the ASCENDING/DESCENDING KEY is defined as a date-time data item.
The Data Division description of identifier-1 must contain an OCCURS clause with the INDEXED BY option. For Format-2, the Data Division description must also contain the KEY IS phrase in its OCCURS clause.