When creating a Meta data field element, the data, which the element does work on/with, is the item_metafield_value.value table and column.

For most scenarios, this is sufficient. However, a meta data field has much more information associated with it, eg. the meta field's label. If the label, instead of the value, is what is needed, then the field "item_metafield_label_label" can be added to the element. An addition of such a field changes the data from item_metafield_value.value to item_metafield_label.label.

There are 5 different fields.

Sortindex

Maps to the table item_combo_value and column sortindex.

A sort index determines how various values are displayed in a combo box. It works exactly like a compare function, in that values with sortindex of 0 will be placed next to each other in no particular order; a higher sort index places a value lower in the combo; a lower sort index places the value higher in the combo.

This field works if a meta data field's data type is a combo. If this field is applied to a meta data field, whose data type is not "combo", the search generation will fail! If in doubt, whether a meta data field has a combo data type, find out or do not use this field.

Item_metafield_label_label

Maps to the table item_metafield_label and column label

The language versioned label associated with a meta data field.

ItemReferenceTitle

If a meta data field is associated with an item, this field will map to that item's title.

ItemReferenceBaseID

If a meta data field is associated with an item, this field will map to that item's base ID (primary key).

ItemGuid

A GUID, which maps directly to a meta data field.