Opal manages databases for two distinct purposes: for holding the participants identifiers and for holding the variable catalog and participant data. Since Opal 3.0, it is not required to set up neither an identifiers database, nor a data database:

  • If no identifiers database is defined, the Identifiers Mappings service when performing import/export will be disabled.

  • If no data database is defined, no data can be imported in any project, only Project Resources can be defined and used for analysis.