My question: what is the use of the fieldnames mapped to null?
These fieldnames are known as reserved words but do not have an alternate fieldname mapped to it.
The effect is dependent on the following attributes (from APIDocs):
Option: enforce.disallowed.fields. if true, the storage layer always fails when encountering fieldnames that are reserved sql keywords, and for which no alternate name is available. If false, the layer will ignore the restriction and attempt to use the reserved word (leaving any errors to the underlying implementation).
By default, this option is false. Note that you can specify this attribute seperately, but the "enforce" attribute of the "disallowedfields" tag overrides this attribute.
Attribute: default-storage-identifier-prefix. A default prefix to place in front of disallowed fieldnames to make them suitabel for use in a storage layer. By default, this option is not set.
-- Pierre van Rooden Mediapark, C 107 tel. +31 (0)35 6772815 "Never summon anything bigger than your head."
