tailieunhanh - Microsoft SQL Server 2000 Weekend Crash Course phần 8

Tìm hiểu về phiên giao dịch Khóa ¼ đọc cam kết - Cho phép các giao dịch để xem các dữ liệu sau khi được cam kết bởi bất kỳ giao dịch trước đó. Đây là mức cô lập mặc định cho SQL Server 2000. ¼ lặp lại đọc - Đảm bảo rằng: Đọc có thể được lặp đi lặp lại. | Session 23 Accessing SQL Server System Information 265 Use INFORMATION_SCHEMA as a prefix for the name of the object you would like to find information about. The basic syntax for using INFORMATION_SCHEMA is as follows SELECT FROM When run from the Query Analyzer this query will produce the output shown in Figure 23-1. Figure 23-1 Querying INFORMATION_SCHEMA tables information Here are some samples of the more frequently used INFORMATION_SCHEMA objects the names are very descriptive though you should consult documentation such as Books Online to verify the view s columns you wish to query. Table information VIEW_TABLE_USAGE TABLE_CONSTRAINTS TABLE_PRIVILEGES TABLES VIEWS Part V Sunday Morning Session 23 266 Sunday Morning Column information COLUMNS VIEW_COLUMN_USAGE KEY_COLUMN_USAGE Constraint information CHECK_CONSTRAINTS CONSTRAINT_COLUMN_USAGE CONSTRAINT_TABLE_USAGE REFERENTIAL_CONSTRAINTS 20 Min. To Go Using System Stored Procedures Using system stored procedures is a black art that can never be mastered in full. Yes you can know them all by heart all 930 of them plus 174 extended stored procedures only to find that the number has increased and that names and parameter types have been changed in the newest release. Until recently no alternative to using system stored procedures was available. Even since the advent of INFORMATION_SCHEMA they remain the most comprehensive set of tools for your SQL Server system. You can use system stored procedures to administer SQL Server to query it for information and to create and drop database objects. In fact SQL Server uses them itself behind the scenes in performing various administrative tasks. Unlike INFORMATION_SCHEMA system stored procedures not only display information but also modify it. Proceed with caution. You can access most of the functionality offered by system stored procedures through the Enterprise Manager interface but it s worth your while to familiarize yourself with the most .