Applicable for advanced database applications Improved performance. The RDBMS has domains, keys, multi-valued and join dependencies 5Ħ OODBMS Architecture OBJECT ORIENTED DATABASE MANAGEMENT SYSTEM OOPL Complex Objects Object Identity Methods & Messages Inheritance Polymorphism Extensibility Computational Completeness DBMS Persistence Disc Management Data Sharing Reliability Security Ad Hoc Querying 6ħ OODBMS Main Features Complex objects Object Identity Encapsulation Classes Inheritance Overriding and late-binding Extensibility Computational completeness Persistence Concurrency Recovery Ad-hoc querying 7Ĩ Storage-Levels RDBMS Storage ODBMS Storage Main or virtual memory Secondary storage Transforming and type checking SQL Main or virtual memory Secondary storage 8ĩ OODBMS Advantages Enriched modelling capabilities Extensibility Support for schema evolution. This compounds on the join feature of query processing The many to many relationship is difficult to express. 4ĥ Relational DBMS Limitations Normalisation (Normal Forms and FDs) sometimes lead to relations which do not exist, or correspond, to entities in the real world. Poor representation of real world entities Poor support for integrity & business constraints. For example, the various library database systems use the same machine-readable cataloguing (MARC) format to support library record data exchange.2 Database Models Transition Hierarchical Data Model Network Data Model Relational Data Model ER Data Model Semantic Data Model Object-Relational DM Object-Oriented DM 2ģ Main Issues Relational DBMS Limitations What is an OODBMS? Advantages and Disadvantages of OODBMS What is an ORDBMS? What is SQ元? Comparison of OODBMS and ORDBMS When to use an OODBMS When to use an ORDBMS 3Ĥ Relational DBMS Limitations Semantic overloading.
DIFFERENCE BETWEEN OODBMS AND RDBMS PDF SOFTWARE
In a heterogeneous distributed database system, different sites might use different DBMS software, but there is additional common software to support data exchange between these sites. Heterogeneous distributed database systems For example, library information systems by the same vendor, such as Geac Computer Corporation, use the same DBMS software which allows easy data exchange between the various Geac library sites. Data exchange between these various sites can be handled easily. Homogeneous distributed database systems use the same DBMS software from multiple sites.
Example of a distributed database system. In a distributed database system, the actual database and the DBMS software are distributed from various sites that are connected by a computer network, as shown in Figure 6.2. Each book catalogue had a barcode field similar to those on supermarket products.
DIFFERENCE BETWEEN OODBMS AND RDBMS PDF MANUAL
In the early 1980s, many Canadian libraries used the GEAC 8000 to convert their manual card catalogues to machine-readable centralized catalogue systems. Example of a centralized database system. With a centralized database system, the DBMS and database are stored at a single site that is used by several other systems too. There are four main distribution systems for database systems and these, in turn, can be used to classify the DBMS. Classification Based on Database Distribution It can be a single-user database system, which supports one user at a time, or a multiuser database system, which supports multiple users concurrently. Classification Based on User NumbersĪ DBMS can be classification based on the number of users it supports. Some examples of object-oriented DBMSs are O2, ObjectStore and Jasmine. The object-oriented models have not caught on as expected so are not in widespread use. Object-oriented database management systems (OODBMS) combine database capabilities with object-oriented programming language capabilities. Object-oriented databases are different from relational databases, which are table-oriented. This model is a database management system in which information is represented in the form of objects as used in object-oriented programming. In recent years, the newer object-oriented data models were introduced. These are all referred to as traditional models because they preceded the relational model. However, they are not commonly used due to their complexity. Other traditional models, such as hierarchical data models and network data models, are still used in industry mainly on mainframe platforms. Well-known DBMSs like Oracle, MS SQL Server, DB2 and MySQL support this model. The most popular data model in use today is the relational data model. Chapter 6 Classification of Database Management Systemsĭatabase management systems can be classified based on several criteria, such as the data model, user numbers and database distribution, all described below.
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