In this section: How to: Reference: |
If a segment instance exists but no data has been entered into one of its fields, that field has no value. Some types of data sources represent this absence of data as a blank space ( ) or zero (0), but others explicitly indicate an absence of data with a null indicator or as a special null value. Null values (sometimes known as missing data) are significant in reporting applications, especially those that perform aggregating functions such as averaging.
If your type of data source supports missing data, as do FOCUS data sources and most relational data sources, then you can use the optional MISSING attribute to enable null values to be entered into and read from a field. MISSING plays a role when you:
WebFOCUS |