在System.Data.SQLite创建/使用用户定义的函数？ [英] Create/Use User-defined functions in System.Data.SQLite?

问题描述

用户定义的函数和放大器;整理顺序
  用户定义的函数和整理顺序完全支持意味着在许多情况下，如果SQLite不具有的功能，你可以把它写自己在你最喜欢的.NET语言。写UDF的，并整理顺序从未如此简单

User-Defined Functions & Collating Sequences Full support for user-defined functions and collating sequences means that in many cases if SQLite doesn't have a feature, you can write it yourself in your favorite .NET language. Writing UDF's and collating sequences has never been easier

我发现在C＃ SQLite的ADO.NET 提供商升在这里找到该位，并有了解如何将文档问题实施/使用用户定义的函数。

I spotted this bit on the C# SQLite ADO.NET provider l found here, and was having problems understanding the documentation on how to implement/use user-defined functions.

谁能怎么解释，或提供任何工作实施这个失去新手？

Could anyone explain how to, or provide any working examples for this lost newbie?

推荐答案

罗伯特·辛普森你可以在你的sqlite查询使用正则表达式功能的一个很好的例子：

Robert Simpson has a great example of a REGEX function you can use in your sqlite queries:

// taken from http://sqlite.phxsoftware.com/forums/p/348/1457.aspx#1457
[SQLiteFunction(Name = "REGEXP", Arguments = 2, FuncType = FunctionType.Scalar)]
class MyRegEx : SQLiteFunction
{
   public override object Invoke(object[] args)
   {
      return System.Text.RegularExpressions.Regex.IsMatch(Convert.ToString(args[1]),Convert.ToString(args[0]));
   }
}

// example SQL:  SELECT * FROM Foo WHERE Foo.Name REGEXP '$bar'

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