TAILIEUCHUNG - Beginning Database Design- P13

Beginning Database Design- P13:This book focuses on the relational database model from a beginning perspective. The title is, therefore, Beginning Database Design. A database is a repository for data. In other words, you can store lots of information in a database. A relational database is a special type of database using structures called tables. Tables are linked together using what are called relationships. You can build tables with relationships between those tables, not only to organize your data, but also to allow later retrieval of information from the database | Building Fast-Performing Database Models Exercises Answer the following questions 1. Which of these apply to OLTP databases a. Large transactions b. High concurrency c. Frequent servicing opportunities d. Real-time response to end-users 2. Which of these apply to data warehouse databases a. Lots of users b. High concurrency c. Very large database d. High granularity 3. Which aspect of a query affects performance most profoundly Select the most appropriate answer. a. WHERE clause filtering b. Sorting with the ORDER BY clause c. Aggregating with the GROUP BY clause d. The number of tables in join queries e. The number of fields in join queries 4. Assume that there 1 000 000 records in a table. One record has AUTHOR_ID 5 0. AUTHOR_ID as the primary key. Which is the fastest query a. SELECT FROM AUTHOR WHERE AUTHOR_ID 50 b. SELECT FROM AUTHOR WHERE AUTHOR_ID 50 213 Part III A Case Study in Relational Database Modeling In this Part Chapter 9 Planning and Preparation Through Analysis Chapter 10 Creating and Refining Tables During the Design Phase Chapter 11 Filling in the Details with a Detailed Design Chapter 12 Business Rules and Field .

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