I've written a utility to handle adding values to data parameters for hand-rolling sql queries. Consumption looks like
我编写了一个实用程序，用于处理为手工滚动sql查询向数据参数添加值。消费的样子
utility.Add("SELECT * FROM MyTable WHERE MyColumn = {0}", myVariable, DBType.TheType);
or
或
utility.Add("UPDATE MyTable SET MyColumn = {0}", myVariable, DBType.TheType);
How should a null value for myVariable be handled?
如何处理myVariable的空值?
- All values should be fully trusted. The responsibility is solely upon the consumer. How would the consumer know that null would be handled anyway?
- 所有的值都应该完全可信。责任完全在于消费者。消费者怎么知道null会被处理?
- null can never work, so it should throw a NullArgumentException. Why go any further?
- null不能工作，所以它应该抛出一个NullArgumentException。为什么再进一步呢?
- null should be automatically interpreted as DBNull.Value since it's the only viable solution. This is a utility, right? Make it utilizable and dry up some code!
- null应该被自动解释为DBNull。因为它是唯一可行的解决方案。这是一个效用，对吧?使它可使用和干燥一些代码!
Optional bonus question: If these arguments were made by three political candidates, what would their parties be? (Please state the home country of such parties)
可选附加问题:如果这些争论是由三位政治候选人提出的，他们的政党会是什么?(请说明这些政党的原籍国)
2 个解决方案
#1
1
Rock the Null Coalescing Op:
Rock the Null合并Op:
In your add put another parm for the =... utility.Add("SELECT * FROM MyTable WHERE MyColumn {0}{1}", myVariable, DBType.TheType);
在您的add put另一个parm为=…实用程序。添加(“从MyTable中选择*，其中MyColumn{0}{1}”、myVariable、DBType.TheType);
When you format the string in the Add method: ... = String.Format(sql,myVariable is null ? " IS " : " = ", myVariable ?? "Null"
当您将字符串格式化为Add method:…=字符串。格式(sql,myVariable是零?“IS”:“=”，myVariable ??“零”
You'll probably want to expound on that a bit, e.g., stick with on parameter and toss in a temp stringbuilder; might have to use a the ?/: construct for the type, too, wherever that's being used. Good luck.
您可能想要详细说明一下，例如，在参数上粘贴，并在temp stringbuilder中抛出;可能也必须为类型使用?/:构造，无论使用的是什么类型。祝你好运。
#2
0
Null is a valid query parameter, you don't need to convert it to DBNull to use it in a query.
Null是一个有效的查询参数，您不需要将它转换为DBNull就可以在查询中使用它。
#1
1
Rock the Null Coalescing Op:
Rock the Null合并Op:
In your add put another parm for the =... utility.Add("SELECT * FROM MyTable WHERE MyColumn {0}{1}", myVariable, DBType.TheType);
在您的add put另一个parm为=…实用程序。添加(“从MyTable中选择*，其中MyColumn{0}{1}”、myVariable、DBType.TheType);
When you format the string in the Add method: ... = String.Format(sql,myVariable is null ? " IS " : " = ", myVariable ?? "Null"
当您将字符串格式化为Add method:…=字符串。格式(sql,myVariable是零?“IS”:“=”，myVariable ??“零”
You'll probably want to expound on that a bit, e.g., stick with on parameter and toss in a temp stringbuilder; might have to use a the ?/: construct for the type, too, wherever that's being used. Good luck.
您可能想要详细说明一下，例如，在参数上粘贴，并在temp stringbuilder中抛出;可能也必须为类型使用?/:构造，无论使用的是什么类型。祝你好运。
#2
0
Null is a valid query parameter, you don't need to convert it to DBNull to use it in a query.
Null是一个有效的查询参数，您不需要将它转换为DBNull就可以在查询中使用它。