New Directions In Database-Systems Research and Development

Prepared for: Chief of Naval Research Arlington, VA 22217In this paper, three new directions in database-systems research and development are indicated. One new direction is the emergence of the multilingual database systems where a single database system can execute many transactions written respectively in different data languages and support many databases structured correspondingly in various data models. Thus, a multi-lingual database system allows the old transactions and existing databases to be migrated to the new system, the user to explore the strong features of the various data languages and data models in the same system, the hardware upgrade to be focused on a single system instead of a heterogeneous collection of database systems, and the database application to cover wider types of transactions and interaction in the same environment. One other new direction is the emphasis of the multi-backend database systems where the database system is configured with a number of microprocessor-based processing units and their disk subsystems. These processing units and disk subsystems are called database backends. The unique characteristics of the backends are that the number of the backends is variable, the system software in all of the backends is identical, and the multiplicity of the backends is proportional to the performance and capacity of the system. Thus, for the first time, a multi-backend database system enables the user to relate the amount of hardware used (i.e., the number of the backends) to the degree of performance gain and capacity growth of the system. The third new direction is the possibility of the multi-host database systems where a single database system can communicate with a variable number and heterogeneous collection of mainframes in several different data languages and allow the mainframes to share the common database store and access. This paper attempts to articulate the background, benefits, requirements and architectures of these new types of database system, namely, the multi-lingua the multi-backend, and the multi-host database systems.DoD STARS Program and from the Office of Naval Research.Approved for public release; distribution is unlimited

Database Queries in Java

In conventional programming languages like Java, the interface for accessing databases is often inelegant. Typically, an entire separate database query language must be embedded inside a conventional programming language for programmers to access the full power and speed of a database. Programmers, though, prefer working entirely from within their conventional programming languages, both for general-purpose computation and for database access. This thesis explores how database operations can be expressed using the existing syntax of conventional programming languages. Programmers are able to write all their code –both general purpose code and database access code– in a single language. To run these database operations efficiently though, algorithms are needed for finding these database operations and optimizing them. This thesis focuses on techniques that can be easily adopted because they do not require changes to existing compilers. Three systems have been developed: Queryll, JReq, and HadoopToSQL. Each system examines the problem from the context of functional-style code, imperative-style code, and MapReduce-style code respectively

Decompiling CODASYL DML into relational queries

A “decompilation ” algorithm is developed to transform a program written with the procedural operations of CODASYL DML into one which interacts with a relational system via a nonprocedural query specification. An Access Path Model is introduced to interpret the semantic accesses performed by the program. Data flow analysis is used to determine how FIND operations implement semantic accesses. A sequence of these is mapped into a relational query and embedded into the original program. The class of programs for which the algorithm succeeds is characterized. Categories and Subject Descriptors: H.2.3 [Database Management]: Languages--data manipuh-tion languages (DML); query languages; CODACYL; H.2.5 [Database Management]: Heteroge-neous Databases-program translatio