An Evaluation of Object-Oriented DBMS Developments (part 2)

Many different groups are engaged in developing standards that use object concepts. These include: • application-specific standards groups, e.g. — CAD Framework Initiative (electrical CAD) — PDES/STEP (mechanical CAD) — PCTE (CASE) — OSI/NMF (telephony; network management) — ANSI X3H6 (CASE) — ANSI X3H4 (IRDS) • groups working on generic object standards — ISO ODP, ANSI X3T3 (Open Distributed Processing) — ANSI X3H7 (Object Information Management) — ANSI X3T5.4 (managed objects) • object-oriented programming language groups, e.g. — ANSI X3J20 (Smalltalk) — ANSI X3J16 (C++) Object concepts are becoming pervasive in standards (the above list is illustrative only, and by no means exhaustive), and many standards that did not previously include object facilities are being extended to include them. Examples include the standards for COBOL, PASCAL, and SQL. The number and range of interest of these groups (as well as the details of the ways their object models or use of object concepts differ) illustrate the enormous scope of the introduction of object concepts into standards. All of these are potentially relevant to object DBMSs, because ODBMSs may be used in many different applications, and hence may be required to store objects conforming to many different object models. Of particular interest in the context of ODBMSs are activities directed specifically toward standards governing the use of object concepts in databases, or in distributed object architectures in which object databases might be components. Standards are a key issue in ODBMSs, since: • the lack of an ODBMS standard is one of the factors that is frequently cited as having restrained the more general use of ODBMSs. • the lack of a standard integrating both ODBMS and relational DBMS capabilities discourages the use of ODBMSs in conjunction with existing relational systems (themselves largely based on the SQL standard). This section describes the key standards activities in this area. Specifically, Section 5.1 describes the proposed standards for ODBMSs developed by the Object Database Management Group (ODMG), an industry consortium of OODBMS vendors. Section 5.2 describes the work by ANSI and ISO standardization committees on object extensions to SQL (known as "SQL3"). Section 5.3 describes the standards for distributed object architectures being developed by the Object Management Group (OMG), an industry consortium of developers and users of object-oriented products. Finally, Section 5.4 compares and contrasts these standards, and discusses some issues relating to integrating them.