BLOB type (HTTP)

For details about additional languages, see:

Use the blob type for binary data.

Although you can store binary-encoded vector data in a blob column, you cannot create a vector index or perform a vector search on the column. Instead, use the vector type to store vector data.

Due to a known issue with filtering on blob, DataStax does not recommend using blob in primary keys.

You can insert binary data as a Base64-encoded string with $binary.

curl -sS -L -X POST "API_ENDPOINT/api/json/v1/KEYSPACE_NAME/TABLE_NAME" \
  --header "Token: APPLICATION_TOKEN" \
  --header "Content-Type: application/json" \
  --data '{
  "insertOne": {
    "document": {
      "example_blob" : {"$binary": "PaPXCr8euFI+x64U"},
      "title": "Example"
    }
  }
}'

If you use $binary, the underlying bytes must represent 32-bit floating point values in big-endian format. The byte sequence must be Base64-encoded, with = padding if needed.

For example:

[0.1, -0.2, 0.3] is "PczMzb5MzM0+mZma"
[0.1, 0.2] is "PczMzT5MzM0="
[10, 10.5, 100, -91.19] is "QSAAAEEoAABCyAAAwrZhSA=="

The following script can binary-encode vectors:

python
import base64
import struct

input_vector = [0.1, -0.2, 0.3]
d = len(input_vector)
pack_format = ">" + "f" * d
binary_encode = base64.b64encode(struct.pack(pack_format, *input_vector)).decode()

BLOB type (HTTP)

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