Restrictions on use of Retrieve Display Values Option (Deprecated)

NOTE: From version 6.0 this option is deprecated and may be removed in later versions. Display values can be retrieved using the project option 'Support Source Display Value Mappings', which can be set when the project is opened or created:

Scope: This option only applies to ServiceNow Source servers

Select this option to retrieve the display value of the field instead of the stored value (for reference fields, the stored value is the sysid of the referenced field).

When using this option, users should be aware that where a field has a set of defined display values (choices) the choice display value will also be returned as the source value when the ‘Retrieve Display Values’ option is selected.

In most cases when migrating ServiceNow to SQL Server it is expected that a Simple Mapping with this option enabled will suffice and the following issues should therefore not apply.  If migrating from ServiceNow to another ServiceNow instance then this option should normally be disabled.

Issues can arise in some mappings/lookups if the source value is not a string type:

For example, field ‘Impact’ is an integer, storing values 1-3. However each of these values has a string display value (e.g. ‘1- Low’)

If the target field is of type varchar, a simple mapping will work correctly whether the ‘Retrieve Display Values’ option is enabled or not. If it is disabled, the stored value (1) will be converted to a string(‘1’) and will populate the target field. However if the target field has a numeric type, the mapping will not work with the ‘Retrieve Display Values’ option because the display value ‘1- Low’ cannot be transformed into an integer.

The same issue occurs if the field is used in a value mapping where the retrieved display value (e.g ‘1-Low’ is converted to the integer equivalent),

based on the choices defined for the field. This integer value is then used to match against rather than the text value.

Similarly, if the retrieve display value is used in conjunction with an assignment mapping, this is likely to cause validation errors at design/run time and errors in calculating assignment expressions (leading to the ‘On error’ path being followed).

If used in conjunction with Lookup queries this is also likely to cause validation errors at design/run time and unexpected ‘no match’ results at run time.

Best practice recommendation is that if the source field is not a String or Reference type and it has display values, to only use it in a simple mapping and to ensure that it is mapped to a string (or varchar / nvarchar) target field.