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 byeKey
. If you are handling the value of a standardized field based on itseKey
, you can ignorepKey
.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 toKVMetadataKey_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 ofpKey
to describe the field.pValue
contains the field's value, stored in an appropriate data type.