MIDAS: management of information for design and analysis of systems T. SREEKANTA MURTHY, Y-K. SHYY and J. S. ARORA Optimal Design Laboratory, Collegeof Engineering, The University of Iowa, lowa Oty, IA 52242, USA The paper describes features, system design and implementation of a database management system called MIDAS. The system has capability to organize data of both relational and numerical models, and meets several important requirements - a good data model, ability to organize large matrix data, handle various data types, simplified data definition and data manipulation languages, dynamic data definition, multiple database organiza- tion, speed of data access, and provision for temporary databases. Tabular and matrix form of data generated and used in design and analysis of system can be conveniently organized. Details of various commands of the database management system MIDAS are presented. INTRODUCTION Management of information has become an extremely important task in computer-aided design and analysis of engineering systems. Organization of large volume of design information is a complex task and requires careful considerations. Complexity in organizing information arises due to several reasons. First, the scientific methods of information management are still in their infancy in the engineering field when compared to sophisticated methods used in business applications. Secondly, the nature and use of engineering design information is different from business information. Thirdly, design information processing needs to consider efficiency aspects, as data is stored and retrieved a large number of times during execution of application programs. Since, a major part of design and analysis work is management of information, significant improvement in designer and application program efficiency can be achieved through better ways of managing such information. Several systems for management of information are available for engineering applications. Systems such as FILES, l GIFTS,: RIM, 3 SDMS,4 SPAR, s PHIDAS 6 and TORNADO 7 have been used in some engineering applica- tions. They have been developed with varying degree of sophistication and have a variety of capabilities. A study was made to find out the capabilities and usefulness of existing data management systems for design and analysis applications. It was found s that use of such systems is limited to special applications for which they were developed. In particular, information programs such as FILES, GIFTS, and SPAR were used for finite element Accepted July 1985. Discussion closes September 1986. 0141-1195/86[030149-08 $2.00 © 1986 Computational Mechanics Publications analysis application. They are closely tied to the finite element analysis program and it is difficult to modify and extend them for design applications. On the other hand information management systems like RIM were found quite useful in integrating general engineering analysis programs, but their applicability to finite element analysis and design optimization is limited. Thus, a need of a good data (information) management system (DBMS) which can deal with organization of both design and analysis data exists. With various requirements (discussed in the next section) in view, a database management system called MIDAS was designed. It was decided to use an existing package as much as possible. RIM is the most advanced system available for scientific database management. It supports relational data model facility. So, it was decided to see if the system can be extended to satisfy the requirements stated above. It was found difficult to extend RIM to have multiple data- bases, to organize large matrices, and to be efficient in handling large data sets and large memory. It essentially meant rewriting the memory management, and data deFmi- tion and manipulation parts. So, it was decided to use RIM as is but add new data definiton and data manipulation subroutines that could be called from a FORTRAN applica- tion program. This subsystem is called MIDAS/R which stands for MIDAS-Relational Data Management System. A second subsystem called MIDAS/N was designed which stands for MIDAS-Numerical Data Management System. MIDAS/N supports numerical data model facility. This subsystem can handle multiple databases, small and large matrices, and small and large memory environment. This paper is intended to discuss the requirements of a DBMS, language facilities, system design and commands available in MIDAS. This will show the features required in a DBMS for engineering applications. REQUIREMENTS OF A DBMS It is important to lay down requirements of a good DBMS before discussing various features of MIDAS. Requirements of a DBMS for design optimization oriented applications differ considerably from requirements of business DBMS. They even differ from those for the computer-aided design (graphics) DBMS. For more discussion on the differences between business and engineering application DBMS, refs. 9 and 10 can be consulted. Before the requirements for a good DBMS are stated, types of DBMS are defined. Context-free DBMS: Such a system is designed to work as a stand-alone package. The application program executes under the control of DBMS, i.e. DBMS acts as the main pro- gram. Thus data manager must be modified or extended when a new application is introduced. Adv. Eng. Software, 1986, Vol. 8, No. 3 149