              Data items in the DATABASE_2 category record details about the\
               database identifiers of the data block.\
\
               These data items are assigned by database managers and should\
               only appear in a data block if they originate from that source.\
\
               The somewhat awkward name of this category (DATABASE_2) is a\
               consequence of the name DATABASE having been already used in\
               the CIF core, but used in a manner different from the usage\
               in mmCIF. Since CIF data names, once adopted, cannot be\
               changed, a new category was created.