# Data transaction
Each data transaction has a data array that contains data to be written. In JSON representation of a transaction the data array is the field
# Data array of a data transaction
The maximum length of an array is 100 elements.
The maximum size of an array is 150 kilobytes.
Each element of an array is an object that has 3 fields:
An array cannot contain two elements with the same
key field is a non-empty UTF-8 string.
At the stage of transaction validation, the
key field is converted from UTF-8 to UTF-16 encoding. The size of the resulting array of 16-bit words must not exceed 100 elements. Thus, the size of the
key must be from 1 to 200 bytes inclusive.
key is being deleted when its
value are not specified.
This functionality becomes available since node version 1.2.0, after activation of feature #15 “Ride V4, VRF, Protobuf, Failed transactions”. Versions 1.2.x are currently available on Stagenet only.
When deleting a key using the JSON representation of a transaction, null is used as the type and value of the key. In one data transaction, keys can be used both for writing and deleting records. The maximum number of keys to be deleted in one transaction cannot exceed 100.
type field specifies the type of the
The size of
value field can be from 0 to 32767 bytes.
# Binary format
See the page Data transaction binary format.