🛢DBMS: Rule (Definitions)

"A specification that controls what data may be entered in a particular column, or in a column of a particular user-defined datatype." (Karen Paulsell et al, "Sybase SQL Server: Performance and Tuning Guide", 1996)

"Objects used to enforce business policies by ensuring that data inserted into a column match a certain pattern or fall with a range of values." (Owen Williams, "MCSE TestPrep: SQL Server 6.5 Design and Implementation", 1998)

"A database object that is bound to a column or user-defined data type that specifies what data can be entered in that column. Every time a user enters or modifies a value (with an INSERT or UPDATE statement), SQL Server checks it against the most recent rule bound to the specified column - for example, for limit checking or list checking. Data entered before the creation and binding of a rule is not checked. Rules are supported primarily for backward compatibility." (Microsoft Corporation, "SQL Server 7.0 System Administration Training Kit", 1999)

"A database object that is bound to columns or user-defined data types, and specifies what data values are acceptable in a column. CHECK constraints provide the same functionality and are preferred because they are in the SQL-92 standard." (Thomas Moore, "EXAM CRAM™ 2: Designing and Implementing Databases with SQL Server 2000 Enterprise Edition", 2005)

"A database object that can be applied to columns or alias data types to enforce domain integrity. Is deprecated and should not be used." (Sara Morganand & Tobias Thernstrom , "MCITP Self-Paced Training Kit : Designing and Optimizing Data Access by Using Microsoft SQL Server 2005 - Exam 70-442", 2007)

"1. A database object that is bound to columns or alias data types, and specifies which data values are acceptable in a column. CHECK constraints provide the same functionality and are preferred because they are in the SQL-92 standard. 2. In Analysis Services, a rule specifies restrictions such as Unrestricted, Fully Restricted, or Custom for security read and read/write role permissions." (Microsoft Technet)