Copy directive

The COPY directive copies values from a source column into a destination column.

Syntax

copy :source :destination [force (true/false)]

The COPY directive copies data from the :source column into the :destination column.

If the :destination column already exists, the force option can be set to true to overwrite any existing data in that column. By default, the force option is set to false. For example, the following directive overwrites the values in col_b with the values in col_a:

copy col_a col_b true

Usage Notes

The COPY directive will copy data from :source if and only if :source column exists. If the :source doesn't exist in the record, the execution will fail with an error.

Copying makes a deep copy of the source into the destination. The type of data from the source in the destination column is maintained as-is.

Example

Using this record as an example:

{
  "id": 1,
  "timestamp": 1234434343,
  "measurement": 10.45,
  "isvalid": true,
  "message": {
     "code": 132,
     "text": "Failure in the temperature sensor"
  }
}

Applying these directives:

copy :timestamp :datetime
copy :message :status

results in this record:

{
  "id": 1,
  "timestamp": 1234434343,
  "datetime": 1234434343,
  "measurement": 10.45,
  "isvalid": true,
  "message": {
     "code": 132,
     "text": "Failure in the temperature sensor"
  },
  "status": {
      "code": 132,
      "text": "Failure in the temperature sensor"
  }
}