Transformations > Lookup transformation > Lookup return fields
  

Lookup return fields

Select the fields to return from the lookup object on the Return Fields tab of the Properties panel.
The Return Fields tab displays all fields from the selected lookup object. By default, the mapping includes all fields in the list in the data flow. Remove fields that you do not want to use.
For Lookup transformations that use a dynamic cache, the task returns the NewLookupRow return field. You cannot remove this field. For more information about the NewLookupRow return field, see Dynamic cache updates.
You can edit the name of a field and edit the metadata for a field. When you edit field metadata, you can change the name, native data type, native precision, and native scale.
For some relational connection types, you can specify the default column value for lookup return fields. You can use a string or an expression for the default value. If you use a string, enclose the string in single quotes, for example, 'ABC'. To see if you can set default values for lookup return fields, see the help for the appropriate connector.
Note: When you change field metadata, you cannot automatically revert your changes. Avoid making changes that can cause errors when you run the task.
You can add a field to the field list if the field exists in the lookup object. To add a field, you need exact field details, including the field name, data type, precision, and scale.
To restore the original fields from the lookup object, use the Synchronize icon. Synchronization restores deleted fields, adds new fields, and retains added fields with corresponding fields in the lookup object. Synchronization removes any added fields that do not have corresponding fields in the lookup object. Synchronization does not revert any local changes to the field metadata.
The following table describes the options that you can use on the Return Fields tab:
Field option
Description
Add Field icon
Adds a field from the selected lookup object. Use to retrieve a field from the object that does not display in the list.
Opens the New Field dialog box. Enter the exact field name, data type, precision, and scale, and click OK.
Delete icon
Deletes the field from the list, removing the field from the data flow.
Sort icon
Sorts fields in native order, ascending order, or descending order.
Find field
Enter a search string to find the fields with names that contain the string.
Options menu
Contains the following options:
  • - Use Technical Field Names. Displays field names by technical field name.
  • - Use Labels. Displays field names by label.
  • - Edit Metadata. Change the name, native type, native precision, or native scale, if applicable for the data type. For some relational connection types, you can set the default value for lookup return fields.
    • When you edit metadata, you can display native names by technical field name or label.
Synchronize icon
Synchronizes the list of fields with the lookup object.
Note: If you select this option, you lose any changes you make to the metadata for return fields.
Ignore in Comparison
When the transformation uses a dynamic cache, by default, Data Integration compares the values in all lookup fields with the values in the associated incoming fields to determine whether to update the row in the lookup cache.
Enable this property if you want Data Integration to ignore the field when it compares the values before updating a row. You must configure the transformation to compare at least one field.
This property is displayed for each field when the Lookup transformation uses a dynamic cache.
Ignore Null Inputs for Updates
When enabled, if the value in the associated incoming field contains a null value, Data Integration doesn't update the column in the cache.
This property is displayed for each field except the NewLookupRow field when the Lookup transformation uses a dynamic cache.
Default is disabled.
Retain existing fields at runtime
If field metadata changes after a mapping is saved, Data Integration uses the updated field metadata when you run the mapping. Typically, this is the desired behavior. However, if the mapping uses a native flat file connection and you want to retain the metadata used at design time, enable the Retain existing fields at runtime option. When you enable this option, Data Integration mapping tasks will use the field metadata that was used when you created the mapping.