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Enriching the semantic types libraries

When you add a dataset, Talend Data Preparation automatically suggests, for each column, the best data type or semantic type that matches the data.

If the semantic type proposed by Talend Data Preparation for one column is not the desired one, you can manually change it by clicking the menu icon in the column header.

This allows you to choose among the list of semantic types present in Talend Data Preparation by default. See Predefined Semantic Types for more information. You can go further by creating your own semantic types, as well as updating or deleting the existing ones, so that Talend Data Preparation speaks your business language.

The semantic types modifications are made directly in the Talend Data Preparation interface, via the Semantic types tab of the left menu.
All the changes are stored using Talend Dictionary Service and are propagated across various Talend products.

The availability of Talend Dictionary Service depends on the license you have.

In Talend Dictionary Service, the semantic types are divided into three main categories:
  • The DICT type, based on an open or closed list of values.
  • The REGEX type that compares your data against a preselected regular expression.
  • The COMPOUND type, under which you can group several existing types.

To enable the interaction between Talend Dictionary Service and Talend Data Preparation, you must fulfill the following prerequisites:

  • Talend Dictionary Service is installed and running.
  • Talend Administration Center is installed and running.
  • You have a Platform licence or a Talend Data Fabric licence.
  • The Dictionary Service User check box is selected for your user in Talend Administration Center.
  • In the <install_folder>\dataprep\config\ file, the dataquality.semantic.update.enable and dataquality.semantic.list.enable properties are set as true.
  • In the <install_folder>\dataprep\config\ file, you have set the URL to your Talend Dictionary Service instance with the semanticservice.url parameter.

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