8 8 Chapter 8 The University Lab: Conceptual Design Verification, Logical Design, and Implementation Database Systems: Design, Implementation, and Management 4th Edition Peter Rob & Carlos Coronel

8 8 E-R Model Verification 4Review of the Conceptual Design Process u Entity sets, attributes, and domains u Composite attributes u Multivalued attributes u Primary keys u Foreign keys u Derived attributes u Composite entities

8 8 E-R Model Verification 4The verification process is used to established that: u The design properly reflects the end user or application views of the database. u All database transactions are defined and modeled to ensure that the implementation of the design will support all transaction-processing requirements. u The database design is capable of meeting all output requirements. u All required input screens and data entry forms are supported. u The design is sufficiently flexible to support expected enhancements and modifications.

8 8 E-R Model Verification 4Tasks of E-R Model Verification u Identifying the central entity u Identifying each module and its components u Identifying each module transaction requirement

8 8 E-R Model Verification 4Problems with the Inventory Management Module: u The Inventory module generates three reports, one of which is an inventory movement report. But the inventory movements are spread across several different entities. Such a spread makes it difficult to generate the output and reduces system performance. u An item’s quantity on hand is updated with an inventory movement that can represent a purchase, withdraw, check-out, check-in, or inventory adjustment. Yet only the withdrawals and check-outs are represented in the model.

8 8 E-R Model Verification 4Solution u Creating a new entity to record all inventory movement; that is, an inventory entity is needed. u Creation of the new entity INV_TRANS serves two purposes as a common entry points: l It standardizes the inventory module’s interface with other modules. l It facilitates control and generation of required outputs, such as the inventory movement report.

8 8 Figure 8.25 The Inventory Transaction Process

8 8

8 8

8 8 The TR_ITEM (Weak) Entity Table 8.26

8 8 The TR_ITEM Sample Data Figure 8.27

8 8

8 8 Logical Design 4The logical design translates the conceptual model to match the format expected of the DBMS that is used to implement the system. 4It sets the stage for creating the relational table structures, indexes, and views.

8 8 Logical Design 4Tables u Example of SQL to create the STORAGE table: CREATE TABLE STORAGE ( LOC_IDCHAR(12)NOT NULL, ITEM_IDCHAR(10)NOT NULL, STOR_QTYNUMBER, PRIMARY KEY (LOC_ID, ITEM_ID), FOREIGN KEY (LOC_ID) REFERENCES LOCATION ON DELETE RESTRICT ON UPDATE RESTRICT, FOREIGN KEY (ITEM_ID) REFERENCES ITEM ON DELETE CASCADE ON UPDATE CASCADE);

8 8

8 8 Logical Design 4Indexes u Indexes are created to enhance operational speed and to enable us to produce logically ordered output sequences. CREATE UNIQUE INDEX LA_DEX ON LAB_ASSISTANT (LA_ID); CREATE UNIQUE INDEX WS_DEX ON WORK_SCHEDULE (SCHED_SEMESTER, LA_ID, SCHED_WEEKDAY, SCHED_TIME_IN);

8 8 Logical Design 4Views u Views are often used for security purposes. However, views are also used to streamline the system’s processing requirements. CREATE VIEW LA_SCHED AS SELECT LA_ID, LA_NAME, SCHED_WEEKDAY, SCHED_TIME_IN, SCHED_TIME_OUT WHERE SCHED_SEMESTER = ‘FALL99’;

8 8 Physical Design 4Physical design requires the definition of specific storage or access methods that will be used by the database. 4It must include an estimate of the space required to store the database. 4Physical storage characteristics are a function of the DBMS and the operating systems being used.

8 8 Table 8.27 Fixed Space Claimed By OS/2 DBM V1.2 Per Database Table 8.28 Physical Storage Requirements: The USER Table

8 8 Implementation 4Database administrator (DBA), who controls the database management function, must define the standards and procedures required to interact with the database. 4The implementation plan includes: u Formal definitions of the processes and standards. u Chronology of the required activities. u Development of adequate documentation standards. u Identification of responsibilities for continued development and maintenance.

8 8 Implementation 4Database Creation u Tables, indexes, and views are created. u Storage space and access methods are implemented. 4Database Loading and Conversion u Data are entered one table at a time or by copying the data from existing databases or files. u Processes may require data to be loaded in a specific order.

8 8 Implementation 4System Procedures u System procedures describe the steps required to manage, access, and maintain the database system. u Procedures must be established to l Test and evaluate the database. l Fine-tune the database. l Ensure database security and integrity. l Back up and recover the database. l Access and use the database system.

8 8 Testing and Evaluation 4The purpose of testing and evaluation is to determine how well the database meets its goals. 4Testing and evaluation should be an ongoing process. 4Testing and evaluation should consider: u Performance measures. u Security measures. u Backup and recovery procedures.

8 8 Operation 4Database operation is an ongoing venture that includes all the DBA’s administrative and technical functions designed to ensure the database’s continuity. u Operational Database An operational database provides all necessary support for the system’s daily operations and maintains all appropriate operational procedures. u Operational Procedures Database operational procedures are written documents in which the activities of the daily database operations are described. u Managing the Database: Maintenance and Evolution The DBA is responsible for coordinating all operational and managerial aspects of the new DBMS environment.

8 8 Operation 4DBA’s Responsibilities u Monitoring and fine-tuning the database u Planning for and allocating resources for changes and enhancements u Planning for and allocating resources for periodic system upgrades u Providing preventive and corrective maintenance u Providing end user management services u Performing periodic security audits u Performing necessary training u Establishing and enforcing database standards u Marketing the database to the organization’s users u Obtaining funding for database operations, upgrades, and enhancements u Ensuring completion of database projects within time and budget constraints