An array length representing a value of DML array or PL/SQL table, or VARRAY and TABLE object types is set equal to a value of the ArrayLength property. If you use DML array or PL/SQL table output parameter you must obligatory set ArrayLength property. If you use output parameter of VARRAY or TABLE type ArrayLength property will be set automatically after command execution.
For PL/SQL parameters, only the following data types are allowed: Boolean, VarChar, Char, NVarChar, NChar, Number, Integer, Double, Float, Date.