Đang chuẩn bị liên kết để tải về tài liệu:
Creating and Managing Tables

After completing this lesson, you should be able to do the following: Describe the main database objects Create tables Describe the data types that can be used when specifying column definition Alter table definitions Drop, rename, and truncate tables | Creating and Managing Tables Schedule: Timing Topic 30 minutes Lecture 20 minutes Practice 50 minutes Total Objectives After completing this lesson, you should be able to do the following: Describe the main database objects Create tables Describe the data types that can be used when specifying column definition Alter table definitions Drop, rename, and truncate tables Lesson Aim In this lesson, you learn about tables, the main database objects, and their relationships to each other. You also learn how to create, alter, and drop tables. Database Objects Object Description Table Basic unit of storage; composed of rows and columns View Logically represents subsets of data from one or more tables Sequence Numeric value generator Index Improves the performance of some queries Synonym Gives alternative names to objects Database Objects An Oracle database can contain multiple data structures. Each structure should be outlined in the database design so that it can be created during the build stage of database development. Table: Stores data View: Subset of data from one or more tables Sequence: Numeric value generator Index: Improves the performance of some queries Synonym: Gives alternative names to objects Oracle9i Table Structures Tables can be created at any time, even while users are using the database. You do not need to specify the size of any table. The size is ultimately defined by the amount of space allocated to the database as a whole. It is important, however, to estimate how much space a table will use over time. Table structure can be modified online. Note: More database objects are available but are not covered in this course. Instructor Note Tables can have up to 1,000 columns and must conform to standard database object-naming conventions. Column definitions can be omitted when using the AS subquery clause. Tables are created without data unless a query is specified. Rows are usually added by using INSERT statements. Naming Rules Table names and column . | Creating and Managing Tables Schedule: Timing Topic 30 minutes Lecture 20 minutes Practice 50 minutes Total Objectives After completing this lesson, you should be able to do the following: Describe the main database objects Create tables Describe the data types that can be used when specifying column definition Alter table definitions Drop, rename, and truncate tables Lesson Aim In this lesson, you learn about tables, the main database objects, and their relationships to each other. You also learn how to create, alter, and drop tables. Database Objects Object Description Table Basic unit of storage; composed of rows and columns View Logically represents subsets of data from one or more tables Sequence Numeric value generator Index Improves the performance of some queries Synonym Gives alternative names to objects Database Objects An Oracle database can contain multiple data structures. Each structure should be outlined in the database design so that it can be created during the build