What is Metadata?
Documents may contain information about the document itself: we call this metadata. For instance, a raster image file contains metadata recording the image's width and height; a word processing document may contain metadata recording the document's author and title. Metadata can be represented by key-value pairs. For instance, a document's title can be represented as the key "Title" and the value "Annual Report". We refer to a single metadata key-value pair as a metadata field.
Containers (documents with subfiles) can contain metadata about their subfiles. For instance, a Personal Folders (.pst
) file is a container that can have multiple email messages as subfiles. A PST file may contain metadata, including the "To" and "From" fields of these subfiles.
Access Metadata using the C++ API
You can access document metadata by calling the metadata() method on a KeyView Document object.
You can access subfile metadata by calling the metadata() method on a KeyView Subfile object.
KeyView uses Metadata
and MetadataElement
objects to represent metadata.
- A
Metadata
object is a container ofMetadataElement
objects, allowing you to iterate over them or look them up by key. - A
MetadataElement
object represents one metadata field.