Domains are XML formatted lists containing valid values for a given property. These lists make data input easier and increase accuracy. They can be embedded in the property definition, defined in a named list that can be shared, read from external ASCII files or created using an SQL query if the feature is connected to a database (RDBMS). Up to six value columns per entry can be defined. For example, a pipe has valid choices of 100, 200, 250, 300, and 500 mm. Only these choices are available via a menu.