希望在允许空值的列中强制唯一性。
You want to enforce uniqueness in a column that allows null values.
资源编译器不允许空菜单。
主键不允许空值。
定义主键以对不允许空值的指定列中输入的值强制唯一性。
Define a primary key to enforce uniqueness for values entered in specified columns that do not allow nulls.
可能的原因包括不允许空密码，登录时间限制，或强制的策略限制。
Possible reasons are blank passwords not allowed, logon hour restrictions, or a policy restriction has been enforced.
获取或设置一个值，该值指示对于属于该表的行，此列中是否允许空值。
Gets or sets a value that indicates whether null values are allowed in this column for rows that belong to the table.
PortletPreferences的preference属性允许空值。
The preference attributes of PortletPreferences allows NULL values.
当将唯一约束附加到允许空值的列时，请确保在约束的列中最多有一行包含空值。
When you attach a unique constraint to a column allowing null values, you ensure that at most one row will have a null value in the constrained column.
可将唯一约束附加到允许空值的列，但是只能将主键约束附加到不允许空值的列。
You can attach unique constraints to columns that allow null values, whereas you can attach primary key constraints only to columns that do not allow null values.
它要求SOAPAction报头必须包含与WSDL中SOAPAction属性相同的值，但是它也允许空的soapaction值。
It mandates the SOAPAction header to contain the exact value of the SOAPAction attribute in the WSDL but it also allows empty SOAPAction values.
毕竟，即便全球玉米或小麦都消耗一空，农民们在气候条件允许的情况下还可再种植，而且事实也的确如此。
After all, if the world runs short of corn or wheat, farmers can simply grow more, weather permitting. That is exactly what they have been doing.
默认情况下，这些字段是空的，并且不允许访问。
人们已经尝试过创造一些允许对房地产进行对冲或做空的工具。
There have been attempts to create instruments that allow property to be hedged or shorted.
在压力确定要来的时期内，如果夫妻双允许有暂时的亲密空窗期，也许会变成彼此生活的准则。
Couples err when they allow the temporary absence of intimacy - during the stressful times that are sure to come - to become the norm of their lives.
前面板控制允许用户设置脉冲宽度与频率或先设置频率与占空因数，再设置脉冲宽度。
The front panel controls allow the user to set pulse width and frequency independently, or to set frequency and duty cycle, which then sets the pulse width accordingly.
这种逆向iff系统允许飞机使用现役1090mhz的IFF异频雷达收发机来询问目标区域，提供近空支援(CAS)，而不是标准的1030mhz。
The Reverse IFF system allows an aircraft providing close-air support (CAS) to interrogate a target area using its existing IFF transponder at 1090 MHz rather than the standard 1030 MHz.
与依赖于特定字段或空表单的默认DominoWeb呈现技术相比，这些产品依赖于传送的HTML，以允许完全控制Web呈现。
Rather than relying on the default Domino Web rendering of a particular field or full form, these products rely on pass-thru HTML to allow full control of the Web rendering.
EmptyVisitor只是提供了所有不同种类的visitor的空的实现，允许您只对感兴趣的visitor方法建子类和重写。
EmptyVisitor just provides an empty implementation of all the various types of visitors, allowing you to subclass and override only the visitor methods of interest.
通过将其他字段保留为空，此连接将成为数据库的通用DB 2连接，从而允许此连接文档提供对数据库中所有可用表的访问权。
By leaving the other fields empty, this becomes a generic DB2 connection to your database, allowing this connection document to provide access to all of the tables available in the database.
这一次，非根用户的能力集是空的，作为根用户启动的进程的允许集和有效集中包含cap _ dac_override。
This time, the non-root user has an empty capability set, while the process started as a root user has cap_dac_override in its permitted and effective sets.
标题(title)，简短的、人类可读的记录主体行；允许使用空字符串(用空的标题元素表示，如)。
A title, which expresses a short, human readable subject line for the entry, and can be a blank string (represented by an empty title element, such as).
在C#中，你可以在一个允许为空的值类型后面加上一个问号（比如，int?x;）。
In C# you can flag a value type as a nullable type by adding ? after the type (like int? x;).
“name”列的类型是CHAR(30)，不允许为空，而且根据此列建立了一个索引。
The "name" column will be a CHAR (30), set to NOT NULL, and have a unique index on it.
对每个列，要确保选择了正确的数据类型，并取消“允许为空”复选框。
For each of the columns, be sure to select the right data type and to uncheck the Allow Nulls options.
控制引擎的空燃比。允许车手根据赛道情况平衡速度和燃料经济性的关系。
Controls the engine fuel mixture level. This allows the driver to balance fuel economy with performance depending on the current race situation.
合模油缸的分流切换系统允许高速开合模，使空循环时间最短。
The differential switching system of the clamping cylinder allows high opening and closing speeds and minimal dry cycle times.
空的选择是不允许的(这通常都是错误)，但如果你真的需要一个空的选择，可以使用(？：)作为占位符，例如。
Empty alternatives are not allowed (these are almost always a mistake), but if you really want an empty alternative use (? :) as a placeholder, for example.
注意：新列必须允许包含空值或者必须指定默认值。
Note: the new column either must allow null values or must be specified with a default value.
注意：新列必须允许包含空值或者必须指定默认值。
Note: the new column either must allow null values or must be specified with a default value.
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