MIS 561 Week 4 Midterm Collection (GRADED A) Questions and Answers | Already RATED A+

(TCO 1) We know that a DBA (Database Administrator) should have knowledge of database structures, such as tables and SQL. List and describe at least four other categories of tasks expected from a DBA. A DBA must ensure that: databases are useful, usable, available, and correct. there is database performance, monitoring, and tuning. there is access authorization and security. there is database backup and recovery. there are interfaces with databases. (TCO 2) Before a newly installed DBMS can be used effectively, standards and procedures must be developed for database usage. Name some of these standards that, if practiced, could help in reducing cost of supporting end users. Your Answer: Standards are common practices that ensure the consistency and effectiveness of the database environment, such as database naming conventions. Procedures are defined, step-by-step instructions that direct the processes required for handling specific events, such as a disaster recovery plan. Failure to implement database standards and procedures will result in a database environment that is confusing and difficult to manage. The DBA should develop database standards and procedures as a component of corporate-wide IT standards and procedures. They should be stored together in a central location as a printed document, in an online format, or as both. Several vendors offer canned standards and procedures that can be purchased for specific DBMS products. (TCO 3) Designing and implementing a physical database from a logical data model is not just a simple matter of mapping entities to tables, attributes to columns, and relationships to referential constraints. Quite a few other database design issues must be addressed. Effective storage planning is part of the physical process design. As a DBA, how do you calculate the amount of storage space usage required to store a table? Your Answer: To calculate the amount of storage required to store a table, the DBA must first establish the row size. This is accomplished by adding up the maximum size of all of the columns, based on their assigned data type and length. An average size can be substituted for variable-length columns. An estimate for the number of bytes required can be calculated by multiplying the row size by the number of rows planned to be stored in the table. Of course, the DBA must also factor in any storage overhead required by the DBMS for things like row and page headers, pointers, and the like. Because each DBMS uses different techniques, each DBMS will have different overhead requirements. TCO 4) When implementing a physical database from a logical data model, you must consider database performance by allowing data in the database to be accessed more rapidly. One way to improve performance is to reduce the number of input/output when requesting data from a database. Which method do you recommend for possible reduced I/O when querying chunks of data? How does it improve the amount of input/output and what are the disadvantages of the method?