An anySimpleType element can contain any atomic datatype, such as string, integer, decimal, or date. Use anySimpleType in a schema when you do not know the datatype of the element in an XML instance document.
When you define an element as anySimpleType, the Designer creates an anySimpleType column for the element when you import the schema. When you use the column in a mapping, the XML Source Qualifier maps this type to a string.