Green 1989 and Millet 1987 . It is something of a truism to say that some source types transfer to tabular form rather better than others do. One problem that historians creating tabular databases have recounted on numerous occasions is the difficulty in making a real world source document 'fit' into the rigid artificial model of the desktop data analysis package. Other analysis systems that can deal with textual non-structured data are available, and many historians have used such tools in the face of the restrictions of purely tabular databases. For examples where researchers have abandoned the formal relational or tabular database approach, see Woollard and Denley 1996 .
Many projects deal with multiple rather than single sources.
Resource creators are advised to consider each particular source on its own merits and evaluate the material's viability or otherwise for digital transference. This could be considered a selection process by which certain materials can be deemed suitable for transcription into database form, whereas creators may deem that other materials present too many difficulties and would not form part of a database. One of the key dangers to avoid is the situation where the project wastes resources on a difficult source because it was not identified as a potential problem at the outset. Historical sources in the real world unfortunately do not always fit neatly into the 'good for tables' or 'bad for tables' categories. Very often a source will in general be suitable for the creation of a highly structured database but will include elements, possibly significant elements, which are not so suitable.