Using metadata
Key/value metadata can be written to entities using the metadata property and also used to query entities.
The metadata property has a similar interface as a dictionary and keys can be printed using the keys method:
>>> print(new_sequence['metadata'].keys())
['frame_padding', 'focal_length']
or items:
>>> print(new_sequence['metadata'].items())
[('frame_padding': '4'), ('focal_length': '70')]
Read existing metadata:
>>> print(new_sequence['metadata']['frame_padding'])
'4'
Setting metadata can be done in a few ways where that later one will replace any existing metadata:
new_sequence['metadata']['frame_padding'] = '5'
new_sequence['metadata'] = {
'frame_padding': '4'
}
Entities can also be queried using metadata:
session.query(
'Sequence where metadata any (key is "frame_padding" and value is "4")'
)