TAILIEUCHUNG - Database Modeling & Design Fourth Edition- P43

Database Modeling & Design Fourth Edition- P43: Database technology has evolved rapidly in the three decades since the rise and eventual dominance of relational database systems. While many specialized database systems (object-oriented, spatial, multimedia, etc.) have found substantial user communities in the science and engineering fields, relational systems remain the dominant database technology for business enterprises. | Generating a Database from a Design 197 create table salesperson sales_name varchar 256 dept_no char 2 primary key sales_name foreign key dept_no references department on delete set null on update cascade create table department dept_no char 2 primary key dept_no create table item item_no char 6 dept_no char 2 primary key item_no foreign key dept_no references department on delete set null on update cascade create table order_item_sales order_no char 9 item_no char 6 sales_name varchar 256 not null primary key order_no item_no foreign key order_no references order on delete cascade on update cascade foreign key item_no references item on delete cascade on update cascade foreign key sales_name references salesperson on delete cascade on update cascade create table order_dept_sales order_no char 9 dept_no char 2 sales_name varchar 256 not null primary key order_no dept_no foreign key order_no references order on delete cascade on update cascade foreign key dept_no references department on delete cascade on update cascade foreign key sales_name references salesperson on delete cascade on update cascade It is worth noting that with all the CASE tools we discuss here the conversion of the logical design to the physical design is quite rudimentary. These tools help create basic database objects such as tables and in some cases indexes. However the advanced features of the database server are often not supported where they are supported the CASE tool is usually behind by two or three software releases. Developing advanced 198 CHAPTER 9 CASE Tools for Logical Database Design physical design features such as multidimensional clustering or materialized views is far beyond the capabilities of the logical design tools we are discussing. Advanced physical database design is often highly dependant on data density and data access patterns. One feature of Rational Data Architect that stands out is that it provides linkages with the automatic computing self-managing .

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