Dict

Replace values matched by dictionary keys.

Parameters

Name	Description	Default	Required	Supported DB types
column	The name of the column to be affected		Yes	any
values	Value replace mapping as in: {"string": "string"}. The string with value "\N" is considered NULL.		No	-
default	Shown if no value has been matched with dict. The string with value "\N" is considered NULL. By default is empty.		No	-
fail_not_matched	When no value is matched with the dict, fails the replacement process if set to true, or keeps the current value, if set to false.	true	No	-
validate	Performs the encode-decode procedure using column type to ensure that values have correct type	true	No	-

Description

The Dict transformer uses a user-provided key-value dictionary to replace values based on matches specified in the values parameter mapping. These provided values must align with the PostgreSQL type format. To validate the values format before application, you can utilize the validate parameter, triggering a decoding procedure via the PostgreSQL driver.

If there are no matches by key, an error will be raised according to a default fail_not_matched: true parameter. You can change this behaviour by providing the default parameter, value from which will be shown in case of a missing match.

In certain cases where the driver type does not support the validation operation, an error may occur. For setting or matching a NULL value, use a string with the \N sequence.

Example: Replace marital status

The following example replaces marital status from S to M or from M to S and raises an error if there is no match:

Dict transformer example

- schema: "humanresources"
  name: "employee"
  transformers:
    - name: "Dict"
      params:
        column: "maritalstatus"
        values:
          "S": "M"
          "M": "S"
        validate: true
        fail_not_matched: true