slide cơ sở dữ liệu tiếng anh chương (27) object-oriented dbmss – standards and systemstransparencies

1 Chapter 27 Object-Oriented DBMSs - Standards and Systems Transparencies © Pearson Education Limited 1995, 2005 2 Chapter 27 - Objectives ◆ Object Management Group (OMG), CORBA, and other OMG standards. ◆ Main features of ODMG Object Standard: – Object model – Object Definition Language (ODL) – Object Query Language (OQL) – Language bindings. ◆ Main features of ObjectStore: – Architecture – Data Definition – Data Manipulation. © Pearson Education Limited 1995, 2005 3 Object Management Group (OMG) ◆ International non profit-making consortium founded in 1989 to address object standards. ◆ Several hundred member organizations including many platform and major software vendors. ◆ Primary aims of OMG are: – Promotion of object-oriented approach. – Development of standards in which location, environment, language, and other characteristics of objects are transparent. ◆ Not recognized standards group but aims to develop de facto standards. © Pearson Education Limited 1995, 2005 4 Object Management Architecture Four areas identified for reference model: Object Model (OM) - Design-portable abstract model for communicating with OMG-compliant object- oriented systems. Object Request Broker (ORB) - Handle distribution of messages between application objects in a highly interoperable manner. Like distributed ‘software bus’ enabling objects to make/receive requests/responses from a provider. © Pearson Education Limited 1995, 2005 5 Object Management Architecture Object Services - Provide main functions for realizing basic object functionality. Many of these services are database-oriented. Common Facilities - Comprise a set of tasks that many applications must perform but are traditionally duplicated within each one. © Pearson Education Limited 1995, 2005 6 Object Reference Model © Pearson Education Limited 1995, 2005 7 Object Model © Pearson Education Limited 1995, 2005 8 Common Object Request Broker Architecture (CORBA) ◆ Defines architecture of ORB-based environments. ◆ Basis of any OMG component, defining parts that form ORB and associated structures. ◆ Some elements of CORBA are: – Interface Definition Language (IDL). – Type model. – Interface Repository. – Methods for getting interfaces/specifications of objects. ◆ Provides static and dynamic mechanism for clients to issue request to objects. © Pearson Education Limited 1995, 2005 9 CORBA ORB Architecture © Pearson Education Limited 1995, 2005 10 Other OMG Specifications ◆ UML provides common language for describing software models. ◆ Meta-Object Facility (MOF), defines common, abstract language for specification of metamodels. ◆ XML Metadata Interchange (XMI) maps MOF to XML. XMI defines how XML tags are used to represent MOF-compliant models in XML. ◆ Common Warehouse Metamodel (CWM) defines metamodel representing both business and technical metadata commonly found in data warehousing and business intelligence domains. © Pearson Education Limited 1995, 2005 [...]... Limited 1995, 2005 Model-Driven Architecture (MDA) x OMG hoped OMA would be middleware standard However: common OO – Microsoft produced DCOM (Distributed Common Object Model), – Sun developed Java, which came with its own ORB, Remote Method Invocation (RMI), – another set of middleware standards emerged with XML and SOAP (Simple Object Access Protocol) x Also e-Business increased pressure on companies... that specifies a standard model for the semantics of database objects Design of class libraries and applications using these semantics should be portable across various OODBMSs © Pearson Education Limited 1995, 2005 17 Object Data Management Group x x x x Between release 2.0 (1997) and 3.0 (late 1999), ODMG expanded its charter to cover the specification of univ ersal object storage standards At same... setting storage standards for object databases The Java binding was submitted to JCP as basis for Java Data Objects (JDO) In 2001, ODMG completed its work and disbanded 18 © Pearson Education Limited 1995, 2005 Object Data Management Group x x x Under its extended charter, ODMG specification covers both OODBMSs that store objects directly and Object-to-Database Mappings (ODMs) that convert and store the... existing OOPLs, and extend programming language with transparently persistent data, concurrency control, recovery, associative queries, and other database capabilities © Pearson Education Limited 1995, 2005 19 Object Data Management Group x Major components of ODMG architecture for an OODBMS are: – Object Model (OM) – Object Definition Language (ODL) – Object Query Language (OQL) – C++, Smalltalk, and Java... Server (MTS) Both the PIM and the PSM are expressed using the UML MDA covers full range of pervasive services already specified by OMG, such as Persistence, Transactions, and Security © Pearson Education Limited 1995, 2005 15 Model-Driven Architecture (MDA) © Pearson Education Limited 1995, 2005 16 Object Data Management Group x x x Established by vendors of OODBMSs to define standards Have produced an... for companies and, rather than helping, middleware may be part of problem © Pearson Education Limited 1995, 2005 13 Model-Driven Architecture (MDA) x x x x MDA is an approach to system specification and interoperability building upon 4 specifications discussed above Based on premise that systems should be specified independent of all hardware and software details Thus, while software and hardware may... collection, or a literal type Only collection objects have identity Use iterator to iterate over collection Ordered and unordered collections: – ordered: traversed first to last, or vice versa; – unordered: no fixed order of iteration © Pearson Education Limited 1995, 2005 29 ODMG Object Model – Built-in Collections Set: unordered collections without duplicates Bag: unordered collections that do allow duplicates... by classes or by other interfaces © Pearson Education Limited 1995, 2005 34 ODMG Object Model - Types, Classes, Interfaces, and Inheritance x x x x Class defines both the abstract state and behavior of an object type, and is instantiable Thus, interface is an abstract concept and class an implementation concept Can specify single inheritance between classes using extends keyword Multiple inheritance... possibly complex structure Literal types decomposed as atomic, collections, structured, or null Values of a literal’s properties may not change Do not have their own identifiers and cannot stand alone as objects Embedded in objects and cannot be individually referenced Structured literals contain fixed number of named heterogeneous elements © Pearson Education Limited 1995, 2005 28 ODMG Object Model - Built-in... applicable MDA addresses complete system lifecycle from analysis and design to implementation, testing, component assembly, and deployment © Pearson Education Limited 1995, 2005 14 Model-Driven Architecture (MDA) x x x x To create an MDA-based application, a Platform Independent Model (PIM) is produced that represents only business functionality and behavior PIM can then be mapped to one or more Platform . 27 Object-Oriented DBMSs - Standards and Systems Transparencies © Pearson Education Limited 1995, 2005 2 Chapter 27 - Objectives ◆ Object Management Group (OMG), CORBA, and other OMG standards. ◆ Main. Object Standard: – Object model – Object Definition Language (ODL) – Object Query Language (OQL) – Language bindings. ◆ Main features of ObjectStore: – Architecture – Data Definition – Data Manipulation. ©. standards. ◆ Several hundred member organizations including many platform and major software vendors. ◆ Primary aims of OMG are: – Promotion of object-oriented approach. – Development of standards