![]() |
Copyright © TIBCO Software Inc. All Rights Reserved |
A null represents data of no value. A null value occurs because no data exists in a field, or data of no value is explicitly assigned to a field. In TIBCO Object Service Broker, null has a value less than any other value.As with all other types of data, a null can assume either a character or numeric syntax. A field that is defined with a syntax of C, UN, V, or W holds a character null. A field that is defined with a syntax of B, P, or F holds a numeric null. The behavior of nulls is determined by their syntax and whether the data is character or numeric. A null field of syntax RD can act as either one.
• When a null is represented by character syntaxes (C, UN, V, or W), its behavior is identical to an empty string ('').
• When a null is represented by numeric syntaxes (B, P, or F), its behavior is different from any other numeric value.
• When an RD null is used as a character syntax, it acts as a character null; when it is used as a number syntax, it acts as a numeric null.
• An occurrence is inserted into a table, no assignment is made to the field, and no default value is specified.
• An occurrence is inserted or replaced into a table and the field is assigned the keyword NULL or an empty string ('') and no default value is specified.
• A new field is added to a table that already contains data. All occurrences for this new field contain null values.
![]() |
Copyright © TIBCO Software Inc. All Rights Reserved |