Labels:text | screenshot | number | font | black and white | parallel OCR: Object Term Relational Term Comment Database Database Object databases store objects and their relationships, with support for encapsulation inheritance, and polymorphism. Relational databases store record data in two- dimensional tables, Relationships between tables are constructed with queries. Class/Extent Table Classes are templates for objects. A class can have definitions for attributes and methods. Tables use a row-and-column structure to hold data. An extent is the set of all objects of a particular class. Object Record An object is on instance of a class. It encapsulates data and behavior. A record is a row of column data; Object ID Row ID (RID) OIDs and RIDs are system-generated values that uniquely identify an object in an (OIDI ODBMS, or a row in an RDBMS. However, traditional RDBMS theory does not require RIDs; some RDBMSes do not create them. Attribute Column Object-dota attributes can map to table columns, Object relationships can be Relationship mopped as foreign key values to columns. . Method Stored Methods are associated with objects, and have the capabilities of the Procedure programming language. Stored procedures are precompiled SQL code; Event Triggers An ODBMS will usually have an object-management mechanism that can trigger Management the execution of methods based on the occurrence of object events. RDBMSes use friggers to execute SQL procedures on the occurrence of data events. Index Index Object indices are conceptually similar to relational indices, The ODMG ODL includes syntax to specify multiple keys for a class. Figure 1: Object-relational structure mappings
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