Please note that the entries @ findagrave are volunteer supplied.
Some people will tackle a small cemetery, record all the burials on a spreadsheet and enter the information into the Find A Grave databases.
Burials in national veterans' cemeteries are entered into Find A Grave, I believe by FaG staff/volunteers. Those cemeteries may be a complete listing of all the burials up to the point the cemetery was entered into the databases. Unless it's a cemetery closed to future burials, it's best to double check with the National Grivesite Locator @ the Vet Affairs site since additional burials may have occurred since the cemetery was first entered into the FaG database.
The other, most common way names get into FaG databases is that family researchers create entries for people in their family/family tree.
With the exception of the first two instances above, you usually won't find every name of every person interred in a cemetery. The only names that will appear are those for whom someone made an entry into the FaG databases.
The main office for the Providence Dioceses Catholic Cemeteries has moved from Providence & is now located @ 80 Saint Marys Dr, Cranston, RI 02920 (401) 944-8383 , just 2 streets south of St. Ann's Cemetery.
The Diocese is beginning to computerise their records so in the future it may become a bit easier to locate burials in St. Ann's and other Diocesan owned cemeteries but for the present, the old rule is still in operation - The cemetery office will need to know DOD to find the burial location for you because their records are only organized by DOD. This is slowly changing but the computerization is a work in progress.
Do note there can be some discrepancies between the records at St. Anns cemetery & those held by the main office on St. Marys Dr.
i.e. - A person in my tree, KIA during WW II but not returned to the US until 4 years after the end of the War was buried in St. Ann's but is not listed anywhere in the records @ St. Anns. He is listed in the records at the main office.
At the time of this soldier's burial in St. Ann's, his older bachelor brother who had died in the 1930's was exhumed and both were buried in the same grave.
In the records held @ St. Ann's, the brother who died in the 1930's is still listed in his original grave although that grave has been empty since around 1949 when the two brothers were buried together. One has to go to the main office in order to learn that the two brothers are now together and the original gravesite for the older brother is empty.