If a column does not allow nulls, and you do not create a default for the column, when a user attempts to insert a row but does not include a value for that column, the insert fails and the SAP ASE server generates an error message.
This table shows the relationship between the existence of a default and the definition of a column as NULL or NOT NULL.
|
Column Null Type |
No Entry, no Default |
No Entry, Default Exists |
Entry is Null, no Default |
Entry isNull, Default Exists |
|---|---|---|---|---|
|
NULL |
Null inserted |
Default value inserted |
Null inserted |
Null inserted |
|
NOT NULL |
Error, command fails |
Default value inserted |
Error, command fails |
Error, command fails |