Null functions

Nulls are special values of the data types supported by workflow system.

Following are brief descriptions of the functions that can be used with null values.

Table 1. Table of functions that can be used with null values
Function	What it does
null()	Returns a null time value.
is_null()	Returns the Boolean value true if the expression evaluates to a null value.
NULL_INT_VALUE_TEMPLATE	Returns the Integer value -1543210987.
NULL_STRING_VALUE_TEMPLATE	Returns the String value <<null>>.

null()

This time function returns a null time value. The only valid operations you can perform on null variables using null() are assignments and equality comparisons for Time data type.

Use the following syntax:

null(time)

where time is the data type. Time is the only supported data type for this function.

is_null()

This Boolean function returns true if the input expression evaluates to a null value; otherwise, the is_null function returns false. The only valid operations you can perform on null variables using is_null() are assignments and equality comparisons for Time data type.

Use the following syntax:

is_null(time_expr)

where time_expr is an expression of type time.

Tip: If it is likely that an expression evaluates to null, always test it using the is_null function, since most operations on a null value are invalid.

NULL_INT_VALUE_TEMPLATE

Use this function when working with CE_Operations parameters to indicate that the workflow system Integer data value is null (Integer value -1543210987).

NULL_STRING_VALUE_TEMPLATE

Use this function when working with CE_Operations parameters to indicate that the workflow system String data value is null (String value <<null>>).