1. A token-based database system comprising: a processing device; and a memory device storing instructions that, when executed by the processing device, cause the processing device to perform operations comprising: accessing in a memory a token database that includes a core model, the core model including one or more core model tokens that provide default functionality; generating in the token database an extended model, the extended model including one or more non-core extended model tokens, the extended model tokens conforming to the core model and referencing the core model tokens; generating in the token database one or more non-core instance tokens, the instance tokens conforming to the extended model and referencing the extended model tokens, each of the instance tokens configured to have zero or more connections connecting to other instance tokens, wherein the token database comprises a plurality of tokens that includes the core model tokens, the extended model tokens, and the instance tokens; associating a token with a version identifier in the token database, the version identifier associated with a system-generated date and time of one or more of insertion, update, and deletion of the token in the token database; and associating a connection with a version identifier in the token database, the version identifier associated with a system-generated date and time of one or more of insertion, update, and deletion of the connection in the token database.