Adobe 65007312 - Photoshop Lightroom Programmer's Manual page 70

C 4: Working with Metadata
HAPTER
Metadata field entries
Each of the entries in the
each metadata field describes a photo in the catalog. Each field can have only one value per photo. The
following entries are recognized within each table:
id
version
title
dataType
metadataFieldsForPhotos
string Required. A unique identifier that allows a plug-in to access this field. The
name must conform to the same naming conventions as Lua variables; that is,
it must start with a letter, followed by letters or numbers, case is significant.
number Optional. If present, defines a version number specifically for this field, distinct
from the version number defined by
definition script.
If you make a change to a field definition that is incompatible with the
previous definition (for example, changing the value of
must bump the field's version number. A migration script can search for
photos that contain the old version of the field and manually migrate values.
string Optional. If this field is displayed in the Metadata panel, this is the localizable
display name. This name should be relatively short, since space in the
Metadata panel is at a premium. A name longer than about 100 pixels is likely
to be truncated on display; however, the full text is shown in the tooltip when
the cursor hovers over the name.
If this item is omitted, the field does not appear in the Metadata panel. This
can be useful for storing private, per-image plug-in information, such as the
image's ID at an on-line service that is the export destination, or other
cross-reference information.
string Optional. If this field is present, Lightroom disallows any other data type from
being stored in this field. Nil is always permitted. You cannot require that a
field have a value.
The value is one of these strings:
— The field value must have a string value.
string
— The field value must have one of the allowed values specified in
enum
the
values
pop-up menu for the field.
— The field value must have a string value. In the Metadata panel, the
url
text field is acccompanied by a button that treats the text value as a URL,
opening it in the user's preferred web browser.
array is a table that describes one metadata field;
schemaVersion
entry. In the Metadata panel, allowed values are shown as a
Adding custom metadata 70
in the outer metadata
), you
searchable