Relational Database Model
Comparing and Contrasting the Relational Database Model and OO Model
The relational database model is based upon tables or relations. In this model, the physical implementation of the database is abstracted away from the user. Users query the database using a high-level query language, such as SQL. The relations are made up of columns, which have headings indicating the attribute represented by that column. Tables have key fields, which can be used to identify unique records. Keys relate tables to each other. The rows of the relation are also called tuples, and there is one tuple component for each attribute or column in that relation. A relation or table name, along with those relation 's attributes, make up the relational schema. Relational Database models are server-centric. When designing a Relational Database, you must create a table for each entity type, choose or invent a primary key for each table; add foreign keys to represent one-to-many relationships; create new tables to represent many-to-many relationships; define referential integrity constraints; evaluate schema quality and make necessary improvements; and choose appropriate data types and value restrictions for each field (if necessary). The real power of relational systems lies in the ability to perform complex queries over the data. Relational systems are well understood, and can be highly optimized in terms of queries, scalability, and storage. There is a uniqueness of table rows and primary keys, as well as ease of implementing future data model changes flexibility and maintainability. To build an effective and efficient application in the relational model, the developer must have a comprehensive knowledge of the tables, and any relationships among them. Object oriented database management systems are viewed as an alternative approach to meeting the demands of more complex data types. The need to handle complex object-centric data as the main data element is the driving force
The relational database model is based upon tables or relations. In this model, the physical implementation of the database is abstracted away from the user. Users query the database using a high-level query language, such as SQL. The relations are made up of columns, which have headings indicating the attribute represented by that column. Tables have key fields, which can be used to identify unique records. Keys relate tables to each other. The rows of the relation are also called tuples, and there is one tuple component for each attribute or column in that relation. A relation or table name, along with those relation 's attributes, make up the relational schema. Relational Database models are server-centric. When designing a Relational Database, you must create a table for each entity type, choose or invent a primary key for each table; add foreign keys to represent one-to-many relationships; create new tables to represent many-to-many relationships; define referential integrity constraints; evaluate schema quality and make necessary improvements; and choose appropriate data types and value restrictions for each field (if necessary). The real power of relational systems lies in the ability to perform complex queries over the data. Relational systems are well understood, and can be highly optimized in terms of queries, scalability, and storage. There is a uniqueness of table rows and primary keys, as well as ease of implementing future data model changes flexibility and maintainability. To build an effective and efficient application in the relational model, the developer must have a comprehensive knowledge of the tables, and any relationships among them. Object oriented database management systems are viewed as an alternative approach to meeting the demands of more complex data types. The need to handle complex object-centric data as the main data element is the driving force
References: Java Framework (undated). Object relational mapping. Frontier Technologies. Retrieved on Saturday, June 19, 2004 from the World Wide Web: http://www.jfwk.com/orm.html Mullen, C. (1999). Mixing DB2 and object orientation. IDUG Solutions Journal. Retrieved on Monday, June 21, 2004 from the World Wide Web: http://www.craigsmullins.com/idug_oo.htm Torres, J.T. (2003). Concurrency and transaction management in an object database. Project proposal. Retrieved on Tuesday, June 22, 2004 from the World Wide Web: http://students.depaul.edu/~jtorres4/se690/formal_project_proposal.html