Abstract: Each element of a database may have multiple versions; the versions are partitioned into branches, and versions of a branch are ordered linearly according to their timestamps. Branches are timestamped and related to one another by a version graph. Each version of an element of a database is represented by a unique identifier, a timestamp, a branch name and a value. A new version of an element associated with a branch is created in response to an operation associated with the branch which would modify the element. An object graph in the database is represented independent of the branches and version; an application coded for elements in one version (and branch) can be reused for the same elements in a different version and (different branch) without any re-coding effort. Methods for long duration transactions, cooperative transactions and schema evolutions are provided.

Abstract: A system and method for database management for providing support for long-term storage and retrieval of objects created by application programs written at least in part in object-oriented programming languages consists of a plurality of software modules. These modules provide data definition language translation, object management, object translation, and persistent object storage service. Such system implements an object fault capability to reduce the number of interactions between the application, the database management system, and the database.

Abstract: A tandem pump equipped with a pair of pump units that are assembled together each having a water inlet and a water outlet. Each water outlet duct is associated with a control chamber which is equipped with a volume control disc which can be operated with click sound. Each water outlet duct is provided an air intake tube with which flexible pipe can be engaged so that air or different kinds of gas can be introduced into water of a fish globe along with the projected water. The pump umits of the tandem pump are in communication with each other so that water can be controllably dispensed via a single water outlet or both water outlets at variable speed or volume. Different kinds of accessories for fish raising can be selectively mounted to both or either of the pump units so as to make the tandem pump to be more effectively employed.

Abstract: A system and method for database management for providing support for long-term storage and retrieval of objects created by application programs written at least in part in object-oriented programming languages consists of a plurality of software modules. These modules provide data definition language translation, object management, object translation, and persistent object storage service. Such system implements an object fault capability to reduce the number of interactions between the application, the database management system, and the database.

Abstract: Apparatus for scheduling at least two concurrent transactions accessing a shared data is provided. When a lock request is granted, the apparatus provides for constructing a history file for the shared data to show each data accessing transaction, and also provides for constructing a serialization graph with each node denoting an active transaction, and each directed edge denoting a dependency between two transactions. The serialization graph is searched for a cycle formed by transactions, and if any is found, the transactions are aborted and restarted.

Abstract: A method is disclosed for concurrency control in a system having both pessimistic and optimistic transactions, comprises the steps of entering locks on objects both for optimistic and pessimistic transactions, and validating an optimistic transaction at commit time by checking that all objects on which said optimistic transaction holds a lock have not become obsolete during the execution of said optimistic transaction. Further, a system is shown enabling optimistic and pessimistic transactions to coexist, comprising a lock table into which locks are entered for both optimistic and pessimistic transactions, a wait queue in which pessimistic transactions are entered to wait for locks held by either optimistic or pessimistic transactions, a conflict table which is referenced to determine if a lock held by a first transaction is a conflict lock with respect to a lock requested by a second transaction, and code connected to the lock table, wait queue, and conflict table.

Abstract: A laterally tearing tape strip torn from a roll having a longitudinal axis. The tape is originally annularly rolled onto the roll. Several cuts extending parallel with the longitudinal axis of the roll extend radially through the tape to divide the tape into a plurality of laterally tearing tape strips. A portion of the tape and therefore each tape strip does not include adhesive over a defined area which serves as a leading edge for each strip, a remaining portion of which does not include adhesive, to facilitate removal of a laterally tearing tape strip from the roll.

Abstract: A data structure and search method for a data base management system. The structure and method allow the locating of a stored record in a massive system in a controlled and small number of mass memory accesses. The data structure is arranged into a plurality of search trees, each defining patent nodes and terminal nodes. The nodes of a tree are hierarchically arranged, and the trees are hierarchically arranged as a whole into levels. The initial search tree and an initial subset of trees, in some cases, are designed to be maintained in a main fast access memory. The remaining trees are kept in mass memory. A plurality of first storage files maintained in the mass memory are associated with terminal nodes of each of the trees except the final trees in the hierarchical structure. Terminating storage files, which are the ultimate repository for information, are associated with terminal nodes of the final trees.