Showing papers by "Bruce G. Lindsay published in 1993"

Heterogenous database communication system in which communicating systems identify themselves and convert any requests/responses into their own data format

Abstract: The invention establishes the context in which data exchanged between dissimilar relational database management systems can be mutually understood and preserved, and data conversions can be minimized. The invention accomplishes this by establishing layers of descriptive information which isolate machine characteristics, levels of support software, and user data descriptions. Optimized processing is achieved by processing the different descriptor levels at different times during the development and execution of the database management systems. Minimal descriptive information is exchanged between the cooperating database management systems. Any data conversions that may be necessary are done only by the receiver of the data, and only at the point where it is necessary to have the data represented in the receiver's native format for processing. For sending and receiving systems which match, data conversion is completely avoided, even when the data may have been forwarded through intermediate DBMS systems which do not match. For sending and receiving systems which do not match, data conversion is minimized. The data conversion routines and tables in each system are also minimized by requiring conversion only INTO a system's native format, never FROM its native format into some other format.

System for managing unit-of-work identifiers when a chained, distributed, two phase commit transaction system is severed

Abstract: A method of managing unit-of-work identifiers in a chained distributed database transaction system. The system has a plurality of processing nodes which are logically connected to form a tree. Normally, each node automatically increments its present identifier at the end of processing each transaction to derive the next transaction identifier. However, in response to a failure condition which results in a severed tree, the distributed database that now reside in the first and second subtrees that result from the severance are forced to consistent states. The transaction identifier is incremented in each of the nodes of the first subtree. Transaction work in the first subtree then proceeds with the incremented identifier. The second subtree is dismantled. In response to a nonfailure condition which results in a severed tree, the distributed database in the first and second subtrees that result from the nonfailure severance is committed to a permanent state. The transaction identifier in each of the nodes of the first subtree is incremented. Transaction work in the first subtree then proceeds with the incremented identifier. A new transaction identifier is generated and propagated to all nodes of the second subtree. Transaction work in the second subtree then proceeds with the new identifier.

SQL/XNF-Processing composite objects as abstractions over relational data

Abstract: An extension to SQL, called the SQL extended normal form (XNF), is discussed. It enhances relational technology by a composite object facility, which comprises not only extraction of composite objects from existing databases but also efficient navigation and manipulation facilities provided by an appropriate application programming interface. The language itself allows sharing of the database among normal form SQL applications and composite object applications. It provides proper subsetting of the database and subsequent structuring, exploiting subobject sharing and recursion, all based on its powerful composite object constructor concept, which is closed under the language operations. XNF is integrated into the relational framework, thus benefiting from the available technology such as relational engine and query optimization. >

Polyglot: extensions to relational databases for sharable types and functions in a multi-language environment

Abstract: Polyglot is an extensible relational-database-type system that supports inheritance, encapsulation, and dynamic method dispatch. It allows use from multiple application languages and permits objects to retain their behavior as they cross the boundary between database and application program. The authors describe the design of Polyglot, extensions to the structured query language (SQL) to support the use of Polyglot types and methods, and the implementation of Polyglot in the Starburst relational database system. >