Access Metadata Fields

This section explains how to process metadata fields using the KeyView API.

Standardized Fields

When KeyView understands the meaning of a metadata field in a document, it outputs that data in a standardized field. Standardized fields are represented as KVMetadataElement objects with an eKey set to a value other than KVMetadataKey_Other. For standardized fields, the following is true:

  • eKey is the standardized field key, which indicates the meaning of the field.

  • pKey is uniquely determined by eKey. If you are handling the value of a standardized field based on its eKey, you can ignore pKey. pKey is provided so that standardized fields can optionally be handled in the same way as non-standardized fields.

  • pValue is converted to a standard type, and, where appropriate, standard units.

Each standardized field is guaranteed to occur at most once in the metadata output. For example, the metadata output will contain zero or one KVMetadataElement objects with eKey equal to KVMetadataKey_Title.

For a full list of the standardized metadata fields, see Standardized Metadata Fields.

Non-standardized fields

Non-standardized fields include user created fields, or fields that are specific to that type of document. KeyView handles these in the following way:

  • eKey is set to KVMetadataKey_Other to signify that it is a non-standardized field.
  • pKey contains a string representation of a field's key. If a field key exists in the document, pKey is set to that string. Otherwise, KeyView generates a value of pKey to describe the field.
  • pValue contains the field's value, stored in an appropriate data type.