Tuy nhiên, khi họ làm, họ nhận được các bản sách giáo khoa mở rộng. Các bản sách giáo khoa là một tập tin PDF chất lượng in, đó là lý tưởng để sử dụng trong lớp học. Nó bao gồm thêm Đưa đĩa CD Linux theo chỉ dẫn. 13. Khi cài đặt hoàn tất, nhấp vào nút. | CHAPTER 7 INTRODUCTION TO SQL throughout the database development process. We will use the following notation in the illustrative SQL commands 1. Capitalized words denote the command syntax. Type them exactly as shown though capitalization may not be required by the RDBMSs. 2. Lowercase words denote values that must be supplied by the user. I 3. Brackets enclose optional syntax. 1 4. Ellipses . . . indicate that the accompanying syntactic clause may be I repeated as necessary. I 5. Each SQL command ends with a semicolon . In interactive mode when I the user presses the RETURN key the SQL command will execute. Be alert I for alternative conventions such as typing GO or having to include a contin- I nation symbol such as a hyphen at the end of each line used in the command. I The spacing and indentations shown here are included for readability and 1 are not a required part of standard SQL syntax. I I DEFINING A DATABASE IN SQL Ị Most systems allocate storage space to contain base tables views constraints indexes and other database objects when a database is created. Because of this the I privilege of creating databases may be reserved for the database administrator and i you may need to ask to have a database created. Students at a university may be s assigned an account that gives access to an existing database or they may be allowed - to create their own database. In any case the basic syntax to create a database is j CREATE SCHEMA database_name AUTHORIZATION owner_user id. The database ị will be owned by the authorized user although it is possible for other specified users to work with the database or even to transfer ownership of the database. Physical stor- ị age of the database is dependent on both the hardware and software environment and is usually the concern of the system administrator. The amount of control over i physical storage that a database administrator is able to exert depends on the RDBMS being used. There is little control possible when using .
