How to register a new data model mapping

How to register a new data model mapping#

Using icoads_r300 imodel as a reference, a data model (imodel) mapping can be understood in this context as:

  • A generic mapping from a defined data model.

    e.g. the IMMA data model (imodel = icoads_r300), which in this case maps core ICOADS variables into the CDM format.

  • A specific mapping from a generic data model.

    e.g. the case of mapping a specific ICOADS collection, where the imodel is built for a specific source and deck (imodel = imma1_sid-dck).

  • A combination of multiple data models in a single CDM mapping.

    e.g. the case of mapping ICOADS.CORE variables and variables stored in the ICOADS supplemental data attachment (c99), this type of model is also source and deck dependent (imodel = imma1_supp_model_sid-dck).

This is a summary of the steps needed to add an imodel to the mapping tool:

  1. Copy the mapping structure of an already existing mapping (e.g. cdm_reader_mapper/cdm_mapper/tables/icoads/r300) to the same folder and re-name it according to the imodel that you are going to add.

  2. Create a copy for each of the CDM tables in your imodel. To access the CDM tables templates available in the tool type:

    table_list = cdm_reader_mapper.cdm_mapper.properties.cdm_tables

  3. Edit the mapping files (*.json) and create the mappings to CDM elements (refer to CDM tables mapping files and descriptors for more information), this can be achieved using one of the following approaches:

    • Direct mapping from an imodel element.

    • Direct mapping via code_tables that can take one or multiple imodel elements.

    • Assignment of a default value.

    • Optionally, add any other mapping functions needed for the new data model to the cdm_mapper.mappings module:

    1. imodel elements attributes

    2. parameterization with input keyword arguments

    3. one or multiple imodel elements

    4. transforming function from/to coded elements other than direct mapping with code tables can be defined here (i.e.: imodel key to CDM value or imodel value to CDM key)

  4. Create Code tables to transform variables if these required a specific key to translate the information into the CDM.

Note

Click on next for a detail description on steps 3 and 4.

Note

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