`TDbfFieldDef`
pt	ro	DbfVersion
	ro	DefaultBuf
	ro	MinBuf
	ro	MaxBuf
		HasDefault
		HasMin
		HasMax
		Offset
		AutoInc
		AutoIncStep
		IsLockField
		IsSystemField
		CopyFrom
pl		FieldName
pl		FieldType
pl		VarLengthPosition
pl		NativeFieldType
pl		Size
pl		NullPosition
pl		Precision
pl		Required