The NOT NULL attribute of column Credit_Line in table ACCOUNT has to be dropped because some other account types have been added that do not have a credit line.
ACCOUNT表中的 Credit_Line列的NOTNULL属性必须删除，这是因为添加了没有信用行的其他账号类型。
Figure 11 shows an assign transform that sets the prefix attribute of Person to null.
图11显示了一个赋值转换，它将Person的prefix属性设置为空。
This tag determines whether or not the field in the name attribute is null.
这个标签确定name属性中的字段是否为空。
If that is null, then the encoding attribute of the DOM stream to be written is used.
如果该设置为空，那么使用将要写入的dom流的编码属性。
However in this case, the link's ref attribute will be set to the value "null," and the link's text content will be hidden unless a flag to show null-link content is set to true.
但是，在这种情况下，这个链接的ref属性会设置为“null”值，而且链接的文本内容会隐藏起来，除非将显示空链接内容的标志设置为true。
However in this case, the link's ref attribute will be set to the value "null," and the link's text content will be hidden unless a flag to show null-link content is set to true.
但是，在这种情况下，这个链接的ref属性会设置为“null”值，而且链接的文本内容会隐藏起来，除非将显示空链接内容的标志设置为true。
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