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System-defined Properties

System-defined properties describe an object’s identity, structure, or computed attributes. Their names begin with _. Some, such as _uniqueid, apply to all objects; others, such as _label, belong to particular object types.

These properties are maintained by ApertureDB. An Update command can change a system-defined property only through a parameter that explicitly supports it. The table lists each property, its update parameter where available, and whether it can appear in constraints:

Object

Properties

Type

Param for Update Command

Can Be Used in constraints

Notes

All Objects

_uniqueid

string

Y

Unique id for the object

_create_txn

number

Y

Transaction id that created the object

Connection

_src

string

N

unique_id of the src of the connection

_dst

string

N

unique_id of the dst of the connection

DescriptorSet

_name

string

Y

Name of the set

_dimensions

number

Y

Dimensionality of the Descriptors

_engines

array

N

List of engines available for KNN

_metrics

array

N

List of metrics available for KNN

_count

number

Y

Number of Descriptors in the Set

_segment_size

number

segment_size

Y

Number of Descriptors on each segment

_max_segments

number

max_segments

Y

Maximum number of segments

_splits

object

N

Number of splits

Descriptor

_label

string

label

Y

_set_name

string

Y

Name of the set the Descriptor belongs to

BoundingBox

_label

string

label

Y

_coordinates

rect

rectangle

N

_area

number

Y

Area (in pixels) of the BoundingBox

Polygon

_label

string

label

Y

_vertices

poly

polygons

N

_area

number

Y

Area (in pixels) of the Polygon

_bounds

rect

N

The smallest rectangle containing the Polygon

Video

_fps

number

Y

Average frames per second

_frame_count

number

Y

Number of frames in the video

_frame_width

number

Y

Width of the frame

_frame_height

number

Y

Height of the frame

Frame

_label

string

label

Y

_frame_number

number

frame_number

Y

_time_offset

string

time_offset

Y

_time_fraction

number

time_fraction

Y

Clip

_label

string

label

Y

_range_type

number

Y

Type describing what type of range (time,frame,pct)

_range_start

number

Y

Start of Clip range

_range_stop

number

Y

End of Clip range

NOTE: Only properties having ‘Param for Update Command’ are modifiable by the user.

NOTE: _uniqueid supports ==, !=, in, and not_in.

Descriptor-set segment_size and max_segments updates are advanced, support-managed settings. Consult support before changing them.