ABAP Runtime Environment (BC-ABA) Initial value of an empty column in a row of a database table . Null values can be processed using Native SQL statements, but they have no equivalent as the content of data objects in ABAP. Only the WHERE condition enables a special condition IS NULL for null values. Changing Open SQL statements (INSERT, UPDATE, MODIFY) generally do not create null values, provided you are not processing a view that does not comprise all columns of a database table. However, depending on the database system , you can also display empty strings as null values. Null values can still arise in database tables if new columns are appended to filled tables. When reading with the Open SQL statement SELECT , null values can be created by aggregate functions or an outer join, but they are converted to initial values of the correct type when passed to data objects.
really, it should be named Null state. It's not a value per se; it only denotes that a value was not specified for a field, so the contents of this field are undefined. It's different than zero or an empty (zero length) string, because these are well defined values. Operations against NULL return either NULL or UNKNOWN and it's a source of confusion for newcomers to relational databases, more even that testing for NULL in a query is done with the operator IS NULL but making a field NULL in an update is done by assigning NULL to the desired field.
The absence of a value. object An item that can be placed on the layout. The following are examples of objects: rectangle, line, ellipse, arc, polygon, polyline, rounded rectangle, freehand, chart, text, symbol, and text field.