It is the length of time the user must wait for the

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Unformatted text preview: lete an operation. • Affects system performance. • Becomes more complex when data are more complex when data are Response time is affected by the physical access time. distributed at different locations. • Logical and physical design can sometimes be and physical design can sometimes be Another factor that can affect response time is how data records are physically distributed on the disk. records are physically distributed on the disk Copyright © 2009-10 Y.M. Cheung, William Tan and Carson Woo 30 Physical Database Design Database Design What is response time? is response time? BUSI 335 Copyright © 2009-10 Y.M. Cheung, William Tan and Carson Woo 31 carried out in parallel. BUSI 335 Copyright © 2009-10 Y.M. Cheung, William Tan and Carson Woo 32 Design Considerations Design Considerations For discussion … discussion • Factors to be considered in choosing a file • Which access method (sequential, indexaccess method (sequential index organization: organization: sequential, direct) will you use for (and why?): – Fast data retrieval – Payroll – High throughput for processing data input and maintenance transactions – Inventory management management – Efficient use of storage space – Protection from failures or data loss – Student records – Minimizing need for reorganization – Accommodating growth – Security from unauthorized use BUSI 335 Copyright © 2009-10 Y.M. Cheung, William Tan and Carson Woo 33 Summary • Data Hierarchy • Different Data/File Organizations – Sequential and Direct (Random) Storage – Sequential Access Method, Indexed Sequential Access Method, Direct (Random) Access Method • Design considerations for physical considerations for physical database design BUSI 335 Copyright © 2009-10 Y.M. Cheung, William Tan and Carson Woo 35 BUSI 335 Copyright © 2009-10 Y.M. Cheung, William Tan and Carson Woo 34...
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This document was uploaded on 03/04/2014 for the course COMM 335 at The University of British Columbia.

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