Metadata Elements
This section explains how to process metadata elements.
Standardized Elements
When File Content Extraction understands the meaning of a metadata field in a document, it outputs that data in a standardized element - a KVMetadataElement object where:
eKeyis the standard key, which indicates the meaning of the element. For a list of standard keys, see Standardized Metadata Elements. The standard key will not be equal toKVMetadataKey_Other.-
pKeyis uniquely determined byeKey. If you are handling the value of a standardized element based on itseKey, you can ignorepKey.pKeyis provided so that standardized elements can optionally be handled in the same way as non-standardized elements. -
pValueis converted to a standard type, and, where appropriate, standard units. -
bHasStandardAlternativeisfalse. bIsSupersededspecifies whether this element has been superseded, meaning that this element exists only to preserve backwards compatibility. An element can be superseded to fix issues with the key or value type. When this value istrue, the same metadata is available through an improvedKVMetadataElementin the sameKVMetadataList.
Each standardized element 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.
Non-standardized Elements
Non-standard elements represent native metadata fields. Some non-standard elements might have been used to create a standardized element, and therefore have a standardized alternative. User-created metadata fields, and fields that are unique to one file format, are usually available only as non-standard elements. For a non-standard metadata element:
eKeyis set toKVMetadataKey_Other.pKeycontains a string representation of a field's key. If a field key exists in the document,pKeyis set to that string. Otherwise, File Content Extraction generates a value.pValuecontains the field's value, stored in an appropriate data type.bHasStandardAlternativespecifies whether a non-standardized element has a standardized counterpart. When this member istrue, this element contains metadata that also exists in a standardizedKVMetadataElementin the sameKVMetadataList. The standardized element might present the metadata with different units.bIsSupersededspecifies whether this element has been superseded, meaning that this element exists only to preserve backwards compatibility. An element can be superseded to fix issues with the key or value type. When this value istrue, the same metadata is available through an improvedKVMetadataElementin the sameKVMetadataList.