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Assigning a data class

Data classification helps you to detect, understand and classify the nature and purpose of the elements contained in the data sources imported in your catalog.

Assigning a data class allows you to categorize and operate on objects which have the same data class.

Talend Data Catalog provides several types of data classes:
  • Data-detected classes detect the nature of data automatically based on predefined enumeration, patterns and regular expressions. The data-detected classification uses the data sampling and profiling capability.
  • Metadata-detected classes detect classes by metadata attributes. They help you to detect data that cannot be identified with the data-detected classification, such as date of birth which do not have unique data patterns. The metadata-detected classification is powered by the MQL capability.
  • Compound classes are based on multiple metadata-detected and data-detected classes.
You can tag objects manually such as columns in a database or fields in a file with a data class. Talend Data Catalog can also suggest you a data class assignment.

Before you begin

  • You have been assigned an object role with the Data Classification Editing capability.
  • Optionally, the data sampling and profiling have been enabled and configured during the metadata import.


  1. Go to the home page of an object.
  2. In the Fields or Columns tab, select a field or a column to open its home page.
  3. In the Data Classifications area, select a data class from the drop-down list.
    Talend Data Catalog can automatically suggest an data class. Click the tick to approve the suggestion or click the cross to reject it.
  4. Click the Commit changes button to save your modification.

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