Index Field

Indexes contain index keys, which define the fields the index is built on. You create an index key by adding an Index Field element under the index.

INDEX FIELD ATTRIBUTES

Field The field you need to index. Typically this is the field by which you filter the database.
OrdinalPosition The Position of this field in a multi-column index.
SortOrder Either Ascending or Descending, depending on how you sort the index.