The nullable button should not be checked.
不应选中可空按钮（nullable button）。
Unfortunately the strongly-typed DataRow classes generated by Visual Studio do not use nullable types.
不幸的是，VisualStudio生成的强类型数据集（strongly-typed DataRow）并没有使用nullable values。
Though most Rails developers do not like to keep constraints in the database, you should consider things like nullable columns.
虽然大多数Rails开发人员都不喜欢在数据库中保留限制，但您应该考虑像空列这样的事情。
Though most Rails developers do not like to keep constraints in the database, you should consider things like nullable columns.
虽然大多数Rails开发人员都不喜欢在数据库中保留限制，但您应该考虑像空列这样的事情。
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