Bình luận không có một giới hạn chiều dài. Tốt nhất là viết nhiều như là cần thiết để tài liệu đầy đủ mã. SQL Server tài liệu cấm làm tổ của nhiều dòng ý kiến . Trong các phiên bản khác nhau và trong các công cụ khác nhau có thể có hoặc không có thể tạo ra một lỗi cú pháp | 211 Chapter 5 Functions Function @@@PROCID TYPEPROPERTY type property Description Returns the identification number of the current stored procedure. Returns information about the datatype. Security Functions SQL Server has introduced many improvements in the area of security. The most important of these is the introduction of the role concept. Roles in SQL Server correspond to roles in MS Transaction Server and groups in Windows NT. In earlier versions of SQL Server users could belong to only one group. This restriction led to problems when a developer wanted to implement more complex security rules. The result was often a security hierarchy of groups where each higher group could perform all activities that lower groups could perform. Unfortunately this model does not always correspond to the requirements of a particular business environment. Some implementations involved a considerable number of groups all of which had to be managed. In SQL Server 2000 and SQL Server one user can be associated with many roles. Thus you can assign a set of permissions to a role and then assign each user a set of required roles. Security functions return information about users roles and their assignments Function Description IS_MEMBER group I roie Indicates whether the current user is a member of a Windows NT group or SQL Server role. IS_SERVERROLEMEMBER role login Indicates whether the current user is a member of the specified server role. 212 SQL Server 2000 Stored Procedure Programming Function Description SUSER_ID login Returns the user s login identification number. SUSER_NAME user_id Returns the user s login identification name. SUSER_SID login Returns the user s security identification number. SUSER_SNAME user_sid Returns the login identification name for the user s security identification number. USER_ID user Returns the database user s identification number. USER Returns the database user name. Text and Image Functions SQL Server does not have an elaborate set of
