} 第二种方式违反了命令-查询分离原则command-query separation principle。CQS是针对方法的经典oo设计原则,该原则指出,任何方法都可能是如下情况之一; 1.执行动作(更新,调整。。。)的命令方法,这种方法通常具有改变对象状态等副作用。并且是void的,没有返回值。 2向调用者返回数据的查询,这种方法没有副作用,不会永...
命令查询分离原则Command-query separation principle 在UML和模式应用一书中,发送给Die的roll消息之后跟随着第二个消息getFaceValue用于提取其新的faceValue,特别是:roll()方法是void的,没有返回值,例如: public void roll() { faceValue=//生成随机数 } public int getFaceValue() { return faceValue; } 为什...
Meyer likes to use command-query separation absolutely, but there are exceptions. Popping a stack is a good example of a query that modifies state. Meyer correctly says that you can avoid having this method, but it is a useful idiom. So I prefer to follow this principle when I can, but...
Command-QuerySeparation Principle: Queries must not modify the instance. WikiMatrix When no arguments are given, then thecommand queriesthe default server. WikiMatrix Thecommand-querydistinction is important to the Eiffel method. WikiMatrix The IDENTIFY DEVICEcommand queriesa particular register on the ...
Separation of concerns is the key motivation behind Bertrand Meyer's Command Query Separation Principle: "The really valuable idea in this principle is that it's extremely handy if you can clearly separate methods that change state from those that don't. This is because you can use queries in...
En 1988, Bertrand Meyer introdujo la idea de Command Query Separation, o CQS, en su libro Object-Oriented Software Construction, para aplicarla al software orientado a objetos. La idea fundamental es que los métodos de un objeto deben dividirse en dos categorías: métodos que...
The form connects to a database, sends a query to that database, then feeds the data, perhaps prepares it by performing additional calculations or pulling in additional data from other sources, and finally passes the resulting data set to another WinForms form which it then presents in a ...
The form connects to a database, sends a query to that database, then feeds the data, perhaps prepares it by performing additional calculations or pulling in additional data from other sources, and finally passes the resulting data set to another WinForms form which it then presents in a ...
Additionally, this design muddies the water with command and query separation, essentially forcing you to enable every "query" method (anything that returns a result) into a command method, which implicitly changes state and has side effects (which query methods are not supposed to have). ...
[], "status": "NonFinding" }, "errorMessage": null, "isTrimmed": false, "queryResults": [ [ "False" ] ], "remediation": { "automated": false, "description": "It is recommended to enable SQL Threat Detection at the server level so that all activities on the server itself and ...