null value
英 [nʌl ˈvæljuː]
美 [nʌl ˈvæljuː]
网络 空值; 遗失值; 零值; 虚值; 空值值
双语例句
- In Java, it is a common practice to assign a null value to a reference type when it is not referencing any object.
在Java中，当引用类型没有引用任何对象时将其赋空值，这是公共的操作。 - An error could occur in the first test and prevent the variable's value from being set, thus resulting in the other tests receiving a null value.
错误可以发生在首个测试期间，并阻止您去设置变量的值，并导致其他的测试接受一个空值。 - By default, a column can contain a NULL value, but if you don't want that, you can append the "NOT NULL" postfix to the field definition.
默认情况下，列可以包含NULL值，但是，如果不想这样，可以在字段定义中附加“NOTNULL”后缀。 - Now, even if the same code segment tries to access p before a value has been assigned to it and it has proper handling of the Null value ( which ideally it should be), then it will behave properly.
现在，即使同一个代码段尝试在对p赋值前访问它，该代码段也能正确处理Null值（在理想情况下应具有的值），然后将具有正确的行为。 - In effect, such a null value is a type of data column overloading, and in this context, a null value might be understood to represent some aspect of the data.
实际上，这类null值是一种数据列重载，并且在这个上下文中，null值可能被理解为表示数据的某些方面。 - In a relational database, you end up with many records with a null value in the fax column ( for instance) for every one or two that utilizes that value.
在关系数据库中，在每一个或两个利用空值的传真列中，通过该空值（例如）您完成了许多记录。 - If the corresponding class, field, or method is not generic, a null value is passed when calling the method.
若相应的类、字段或方法非泛型，则在调用方法时将返回null值。 - It's the situation where, for instance, someone passes a null value to a method not coded to handle nulls.
比方说，把null值传入一个并未编写如何处理null值的方法中，这就是一种边界情况。 - When an array variable is NULL or when the element being assigned is in a position beyond the current cardinality, all the elements between the old last element and the new one are implicitly assigned the NULL value.
在阵列变量为NULL或被指定的元素位于超过当前基数的位置上时，最古老的元素和新元素之间的所有元素都被隐式分配NULL值。 - This line also traps for a null value and converts it to an empty string to prevent problems during later processing.
这一行代码也会专门处理null值，它将null值转换为一个空字符串以避免后面的处理出现问题。 - Listing 3 initializes a new Zend_Soap_Server object in non-WSDL mode, passing a null value as the first argument to the object constructor.
清单3传递一个null值到对象构造函数的第一个参数，以非WSDL模式初始化了一个新的ZendSoapServer对象。 - As Linda stated, the behavior is simple: If someone calls push() with a null value, the stack should throw an exception.
正如Linda所说，行为很简单：如果有人对null值调用push（），那么栈应该抛出一个异常。 - Otherwise, the shell interprets the trailing text as part of your variable name& and most likely returns a null value.
否则，Shell将把尾随文本解释为变量名称的一部分&并且很可能返回一个空值。 - What if someone inadvertently passes in a null value for the Class parameter?
如果有人不经意地为Class参数传入一个null值会怎么样呢？ - The description column is left empty, which means it will have a NULL value.
description列留为空白，这意味着它将具有NULL值。 - If nullable, it will contain the NULL value.
如果可为空，它将包含NULL值。 - If this column is not sorted, a null value is returned, and the@ formulas in the agent will not continue executing.
如果该列未进行排序，将返回空值，代理中的@formulas将不再继续执行。 - This marker is usually called the null value, the null list, or the null pointer.
这个标记通常称作空值（nullvalue）、空列表（nulllist）或者空指针（nullpointer）。 - This is a good start, but you need to provide something other than a null value when the Tree Viewer asks for the column text for a particular item.
那是一个很好的开始，但是当为了一个特殊的条目，TreeViewer需要栏目文本时，您需要提供一些内容，而不仅仅是一个零值。 - But, in DB2 z/ OS if a UNIQUE index is created on a column, then only one NULL value can be inserted into it.
但是在DB2z/OS中，如果在列上创建UNIQUE索引，那么只能在其中插入一个NULL值。 - A general, good practice is not to allow null ( that is, no value) columns in a relational database, because when you attempt to read such a column, you get a null value exception.
通常，一种优秀的实践就是不要在关系数据库中使用null（即没有值）列，因为当您试图读取这类列时，您将得到一个null值异常。 - On Linux and UNIX platforms, a NULL value defaults to the primary group of the instance owner, which by default after an installation only contains the user ID of the instance owner.
在Linux和UNIX平台上，NULL值被缺省地赋给实例所有者的主组，完成安装后，缺省情况下这个组只包含用户ID和实例所有者。 - That means a reference type can have a null pointer, but a value type cannot have a null value.
这意味着引用类型可能有空指针，但是数值类型不能有空值。 - This new validation will enforce NOT NULL column constraints by rejecting null values, but only in situations where your database would reject a null value.
这种校验会通过拒绝空值，强迫加上非空[NOTNULL]字段的约束，但是也只有在这种情况下，你的数据库会拒绝空值。 - For database-level entities a one-part name is accepted, with a null value meaning "current database".
对于数据库级实体，只接受由一部分组成的名称，空值表示“当前数据库”。 - Column '% ls' in the specified edge table has an invalid or null value.
指定边缘表中的列''%1！''的值无效，或该值是空值。 - A null value if the provider does not support catalogs.
如果提供程序不支持目录，则为空值。 - If no match is found within the input, a null value is returned.
如果在输入中未找到匹配项，则返回空值。 - Null value is not allowed in unique index or primary key.
唯一性索引或主键中不允许有空值。 - Warning: Null value eliminated by aggregate or other set operation.
警告：聚合或其它集合操作消除了空值。