A policy contains data domains. A data domain describes the functional meaning of a column based on the column data or the column name. For example, a Social_Security data domain contains all database columns with numbers in the following format: 999-99-9999. A Salary data domain might include the Salary, Bonus, and Commission columns in a database.
A data domain contains data masking rules. A data masking rule is a data masking technique to mask a specific type of data. For example, you might configure the Substitution data masking technique for First Names and Last Name columns. You configure two Substitution masking rules because each rule contains different parameters.
You can configure data domains, rules, and policies separately. Apply the rules to data domains and add the data domains to a policy. After you define the policy, you can assign the policy to a data source in a project. You can apply a policy to multiple projects.