Sample: this entity, along with the determination entity, is the core of the database. It holds the latitude, longitude and depth where each sample was taken. It also includes information on when the sample was taken, how accurate the location information is, who to contact for more information, etc. Each sample can hold information on multiple taxa, if multiple taxa were recorded from the same sample.In addition, there are accessary entities that hold information on literature citations and contact information for people or organizations.
Taxon: holds information on each taxon represented in the database, including who first described it, when, what the original reference was, whether it is currently considered a valid taxon or is a synonym of a valid name, and what the taxonomic rank of the name is. The database is designed to categorize taxa by linnean rank (Kingdom, Phylum, etc.). At present, information down to species level is recorded. However, the structure of the database can handle subspecific ranks if desired.
Determination: This is the entity that links Sample and Taxon information together. It records who assigned a given taxon name to organisms found in a given sample.
Specimen: For each determination, this entity records whether there was a specimen preserved, where it is held, and who is responsible for it. It is designed to hold sufficient information to allow an interested party to find and request to view the specimen.
DataSet: The OBIS database targets data that have been reviewed by an expert systematist, which is generally imported as a data set. This entity records information about who provided the data set, when, what processing steps were done on the data, etc.