通过正则表达式提取值

Question

我正在使用动态数据并应用唯一密钥和其他数据库级验证，我已覆盖SubmitChanges函数。

这给了我原来的错误，我能够展示给最终用户。但是，此消息是这样的：

Violation of UNIQUE KEY constraint 'UK_CountryName_Country'. Cannot insert duplicate key in object 'dbo.Country'. The duplicate key value is (America). 
The statement has been terminated. 

我需要的信息的以下关键字：

1. UNIQUE KEY
2. UK_CountryName_Country
3. 美国

我已经写了下面的正则表达式：

System.Text.RegularExpressions.Regex.Split(e.Message.ToString(), "^Violation of (UNIQUE KEY){1} constraint '([a-zA-Z_]*)'. Cannot insert duplicate key in object 'dbo.([a-zA-Z]*)'. The duplicate key value is ") 

我已成功获得＃1 &＃2，但是＃3。

任何人都可以帮助我。另外，有没有更好的方法来实现它。仅供参考：我也会捕获其他类型的数据库错误。

感谢

Answer 1

用你的例子exp ression，似乎您试图匹配Country从dbo.Country而不是America，你问，所以我同时在我的表达/代码：

Dim ExpressionText As String = "^Violation of (?<KeyType>.*?) constraint '(?<ConstraintName>[^']*)'\.[^']*'(?<ObjectName>[^']*)'[^(]*\((?<KeyValue>[^)]*)\)" 
Dim SearchText As String = "Violation of UNIQUE KEY constraint 'UK_CountryName_Country'. Cannot insert duplicate key in object 'dbo.Country'. The duplicate key value is (America). " _ 
           & vbCrLf & "The statement has been terminated." 
Dim regex As New System.Text.RegularExpressions.Regex(ExpressionText) 
Dim mc As System.Text.RegularExpressions.Match = regex.Match(SearchText) 

Response.Write(mc.Groups("KeyType").Value)   ' writes UNIQUE KEY 
Response.Write(mc.Groups(1).Value)     ' writes UNIQUE KEY 
Response.Write(mc.Groups("ConstraintName").Value) ' writes UK_CountryName_Country 
Response.Write(mc.Groups(2).Value)     ' writes UK_CountryName_Country 
Response.Write(mc.Groups("ObjectName").Value)  ' writes dbo.Country 
Response.Write(mc.Groups(3).Value)     ' writes dbo.Country 
Response.Write(mc.Groups("KeyValue").Value)   ' writes America 
Response.Write(mc.Groups(4).Value)     ' writes America 

表达的设计是非常宽容的错误的类型消息，因为还有其他可能违反的键约束条件。我无法找到可能的错误的列表，但这里是表达的一个细分：

^Violation of     # Match literal text 
(?<KeyType>.*?) constraint  # Capture the words that come before " constraint" 
'(?<ConstraintName>[^']*)'\. # Capture whatever is inside the single quotes: ' 
[^']*       # Match anything up to the next single quote 
'(?<ObjectName>[^']*)'   # Capture whatever is inside the single quotes 
[^(]*       # Match anything up to the next open parentheses: ( 
\((?<KeyValue>[^)]*)\)   #Capture whatever is inside the parentheses 

，如果你不想使用命名捕获组可以摆脱那种样子?<Something>的部件，并只想使用数字

Answer 2

由于最后一个值是接近你可以匹配到行的末尾，小心不匹配的最后期限结束：

".... The duplicate key value is (.*)\.$" 

Answer 3

^Violation\s+of\s+(.*?)'(.*?)'.*?\((.*)\) 

我不知道如何所有可能的错误看起来像但上面的正则表达式会捕获：

Group 1: UNIQUE KEY constraint  
Group 2: UK_CountryName_Country 
Group 3: America