设置数据库字段的默认值.

或者更好的是，您可以在Crystal Report字段上设置一个条件，以在其值显示为null时显示该默认值.

Set the default value for your database field.

Or better, you could set a condition on the crystal report fields to display this default value whenever their values are displayed as null.

阅读SQL中的默认约束服务器.它们仅用于这种情况.如果未指定，则输入特定值.
阅读:此处. [

Read about Default Constraints in SQL Server. They are for scenario''s like this only. To enter certain value if not specified.
Read: here.[^]