This image shows a portion of the App.config file open. The below two blocks of code is highlighted.

<dataSources>
        <dataSource alias="orcl" descriptor="(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=localhost)(PORT=1521))(CONNECT_DATA=(SERVICE_NAME=PDBORCL))) "/>
      </dataSources>


<connectionStrings>
    <add name="OracleDbContext" providerName="Oracle.ManagedDataAccess.Client"
      connectionString="User Id=hr;Password=hr;Data Source=orcl"/>
  </connectionStrings>