Substructure storage format

Support software must be developed in each of these areas and integrated into the DBMS for every new abstract data t3q>e. For example, to create a chemical structure ADT, a storage format, such as a connection table format, must first be defined. Then operators for full structure, substructure, and other types ol structure searches must be defined. Access methods need to be implemented to provide fast structure searches and finally, the characteristics of the various structure searches must be made known to the query optimiser to allow efficient overall query execution. 

MAECIS contains five major sections that are integrated into a single system. At its center is a database management system that handles the storage and updating of data and chemical structures. Associated with this section is an information retrieval section that allows one to search the database for specific information composed of any combination of data and/or substructures. Once information is retrieved, it can be displayed on a computer terminal or sent to a printer for hardcopy output using the display section of MAECIS which includes the ability to display chemical structures in various formats. The final two sections of MAECIS allow for the manipulation of chemical structures and the calculation of various molecular properties that are related to chemical structures. 

The atom connection table has been used for many years, mainly for storage and retrieval of chemical structures and substructures. CAS became the first major user of connection tables when the Chemical Registry System was established. It was then followed by Telesystemes-DARC (Description, Acquisition, Retrieval, and Correlation) devised at the University of Paris. In comparison with the CAS format, that used in DARC was definitely more compact and easier to process on minicomputers. 

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