UpdateBlob Command¶

This command provides ways to find one or more existing blob of data and then lets an application add, change or remove properties. The local id allows an application to chain this command with following operations or associate with a previous search.

Parameters¶

• [optional] _ref: for reference

Blocks¶

• [optional] properties
• [optional] remove_props
• [optional] constraints

NOTE: At least one of _ref or constraints are required for searching.

If _ref is provided, it essentially refers to the search results of a previous FindBlob or AddBlob. Since the Update call just results in updating the property values inline within those entities, we keep the same _ref value. The call can result in an update to multiple entities depending on the search criteria. Unique is not assumed to be true in this case.

Property keys are case sensitive and are matched exactly when updating properties.

If search results are empty, this will cause an exception.

Examples¶

The following Python example adds an audio file to VDMS and uses UpdateBlob to add the length property and remove the color property:

from pathlib import Path
import vdms

db=vdms.vdms
db.connect()

audio_blob = [Path("audio_file.m4a").read_bytes()]

all_queries = [
    {
        "AddBlob":
        {

            "_ref": 12,

            "properties": {
                "Name":"blob-sample-1",
                "color": "true",
                "file":"audio"
            }
        }

    },
    {
        "UpdateBlob" : {

            "constraints": {
                "Name" : [ "==",  "blob-sample-1" ]
            },
            "remove_props" : [ "color" ],
            "properties": {
                "length" : 200
            }
        }
    }
]

response, response_arr = db.query(all_queries, audio_blob)