Add missing types. Start moving the database code out of the model file and into each of the model definitions. We will deal with duplicated code when we run into it.
Add missing types. Start moving the database code out of the model file
and into each of the model definitions. We will deal with duplicated
code when we run into it.

materials-commons/materialscommons.org,materials-commons/materialscommons.org,materials-commons/materialscommons.org,materials-commons/materialscommons.org,materials-commons/materialscommons.org