| Reference Mode |  |
| If a table field is defined with a reference, the table field can have one of the following reference modes. Mandatory The table field must contain a value that is present in the reference table. Mandatory unless empty The table field can be empty. If the table field is filled, its value must be present in the reference table. Not mandatory The table field can contain a value that is present in the reference table, but the table field can also contain an other value. |