A method of assuring that each of a plurality of contemporaneously active database transactions comprising at least one read transaction and at most one update transaction has a consistent view of a database storing a plurality of versions of a relation. A transaction has a consistent view of a database if the data available to a transaction are not changed during its execution. An access dictionary is stored comprising an array of access blocks each defining the database location of one of the ...

A database system is provided in a network system capable of exchanging medical data, including at least image data and key data associated therewith, and can store and retrieve the medical data via the network system. The database system has first and second data file devices and a file management device. The first data file device stores image data supplied via the network system in a first rewritable storage. The second data file device stores image data transferred from the first storage in ...

In a storage system including a semi-permanent database there is provided apparatus for updating said database comprising: instrumentalities for reading magnetically recorded data and storing said data in said database; a rotatable drum having an exterior circumferentially-extending surface, said drum including a plurality of protrusions extending beyond said exterior surface; a flexible magnetic card including database updating data magnetically recorded on a major surface thereof, said card ha...

One of a series of hardware/firmware instructions for converting a general purpose digital computer into a database machine by adding the capability of handling data base records. The invention comprises a hardware/firmware implemented machine instruction apparatus which fetches a record descriptor containing a referenced data base record type from main memory. The record type of the record to be checked, which is pointed to by a base register, is also fetched from main memory, and a comparison ...

One of a series of hardware/firmware primitives is disclosed for converting a general purpose digital computer into a database machine. The invention comprises a hardware/firmware implemented machine instruction which determines the appropriate register where a database pointer is currently stored, retrieves the pointer from that register and then stores the pointer into main memory.

A method of generating a backup copy of a database system. Modifications made to the database since the generation of a prior backup copy are summarized in a bit map on a page basis. When the next backup copy is made, only modified pages are transmitted and merged with the prior copy. Plural backup passes are made. New modifications are allowed to occur to the database on all but the last pass. Any database modification made at an address that has already been examined during a pass is backed-up...

A database system for maintaining accounting records in relation to usage of postage meters is disclosed. The database system is provided with two computers, both of which provide access to the system from remote postage meters via a telephone network, and each computer maintains a separate database. One computer acts as primary and handles all transactions, received either direct or via the other secondary computer, and maintains a primary database. For each transaction, the primary computer cr...

A database processing device executes concurrent processing in accessing a database through a plurality of independent terminal units. The database processing device, upon updating data stored in a record after reading out the data stored in the record in the database and correcting or altering the data through a specific terminal, confirms whether or not the data stored in the record has been updated by terminals, and executes updating only when the data has not been updated. The data stored in...

Each network node in a communications network maintains its own copy of the network topology database defining network resources. Each resource record contains a "timer" field which is initially set to a maximum value but which may be decremented on a daily basis. If the timer field is decremented to zero without being reset, the node unilaterally removes the resource record from its copy of the database. The timer field will normally reach zero only for obsolete resource records since each netw...

Method and apparatus for reducing call setup time for calls to Advanced 800 customers by eliminating one database query. (Toll charges for 800 calls are paid by the called customer.) In the prior art, a call to an Advanced 800 customer required accessing a Basic 800 database, then, using data obtained therefrom, accessing an Advanced 800 database. In accordance with this invention, a table of the most frequently called Advanced 800 numbers and the corresponding data normally obtained from the Ba...