MISY430 Lecture Notes - Lecture 9: Data Management, Foreign Key, Object-Relational Database

• School: University of Delaware
• Department: Management Information Systems
• Course: MISY430
• Professor: Mendelsohn Emilio

Document Summary

Data management layer includes: data access and manipulation logic, storage design. 4-step design approach: select format of storage, map problem-domain objects to object persistence format, optimize the object persistence format, design the data access & manipulation classes. Object persistence formats files (sequential and random access) Random access files: efficient for operations (read, write, search) inefficient for report writing. Master files: stores core information (order and customer data, usually held for long periods, changes require new programs. Look-up files (zip codes with city and state names) Transaction files: info used to update a master file, can be deleted once master file is updated. Audit file: records data before & after changes. History file: archives of past transactions. Most popular way to store data for applications. Consists of a collection of tables: primary key is a unique identifier of each row, foreign keys establish relationships b/w tables matched properly. Referential integrity ensures records in different tables are.