T-SQL 正则表达式(CLR 实现)

xman_78tom 2010-06-23 10:01:58

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创建程序集 ClrRegExClass.cs，
并使用 C:\Windows\Microsoft.NET\Framework\v2.0.50727\csc.exe /target:library ClrRegExClass.cs 编译为 ClrRegExClass.DLL 文件。



using System;

using System.Data;

using System.Data.SqlClient;

using System.Data.SqlTypes;

using Microsoft.SqlServer.Server;

using System.Text.RegularExpressions;



public partial class RegExp

{

// 验证字符串中是否包含与指定的匹配模式一致的字符串

    [SqlFunction(IsDeterministic = true, IsPrecise = true)]

    public static SqlBoolean RegExIsMatch(SqlString expression, SqlString pattern)

    {

        return new SqlBoolean(Regex.IsMatch(expression.ToString(), pattern.ToString()));

    }



// 替换字符串中与指定的匹配模式一致的字符串

    [SqlFunction(IsDeterministic = true, IsPrecise = true)]

    public static SqlString RegExReplace(SqlString expression, SqlString pattern, SqlString replacement)

    {

        return new SqlString(Regex.Replace(expression.ToString(), pattern.ToString(), replacement.ToString()));

    }



// 提取字符串中与指定的匹配模式一致的字符串

    [SqlFunction(IsDeterministic = true, IsPrecise = true)]

    public static SqlString RegExSubstring(SqlString expression, SqlString pattern, SqlInt32 position, SqlInt32 occurrence)

    {

        if (expression.ToString().Length < position) return new SqlString("");

        if (position <= 0) position = 1;

        if (occurrence <= 0) occurrence = 1;



        Match m = Regex.Match(expression.ToString().Substring((int) position - 1),pattern.ToString());

        for (int i = 1; i < (int)occurrence; i++)

        {

            m = m.NextMatch();

            if (!m.Success) return new SqlString("");

        }



        return new SqlString(m.ToString());

    }



// 计算字符串中与指定的匹配模式一致的字符串的数目

    [SqlFunction(IsDeterministic = true, IsPrecise = true)]

    public static SqlInt32 RegExCount(SqlString expression, SqlString pattern, SqlInt32 position)

    {

        if (expression.ToString().Length < position) return 0;

        if (position <= 0) position = 1;



        MatchCollection ms = Regex.Matches(expression.ToString().Substring((int)position - 1), pattern.ToString());



        return new SqlInt32(ms.Count);

    }



// 查找字符串中与指定的匹配模式一致的字符串的位置

    [SqlFunction(IsDeterministic = true, IsPrecise = true)]

    public static SqlInt32 RegExIndex(SqlString expression, SqlString pattern, SqlInt32 position, SqlInt32 occurrence)

    {

        if (expression.ToString().Length < position) return 0;

        if (position <= 0) position = 1;

        if (occurrence <= 0) occurrence = 1;



        Match m = Regex.Match(expression.ToString().Substring((int)position - 1), pattern.ToString());

        for (int i = 1; i < (int)occurrence; i++)

        {

            m = m.NextMatch();

            if (!m.Success) return 0;

        }



        return new SqlInt32(m.Index + 1);

    }

}

将程序集 ClrRegExClass.DLL 导入 SQL Server，并创建相应的函数。



// 启用 SQL Server 的 CLR 支持

exec sp_configure 'clr enabled',1;

go

reconfigure

go



// 导入程序集

if exists (select * from sys.assemblies where name='RegExp')

 drop assembly RegExp;

go

create assembly RegExp authorization dbo

from 'fullpath\ClrRegExClass.dll'

with permission_set=safe;

go



// 创建函数

// @expression 为输入的字符串；@pattern 为正则表达式；

// @position 为字符串开始的位置；@occurrence 为与指定的匹配模式一致的字符串出现的次数



if object_id('dbo.regex_ismatch','FS') is not null

 drop function dbo.regex_ismatch;

go

create function dbo.regex_ismatch

(@expression nvarchar(max), @pattern nvarchar(max))

returns bit with returns null on null input

as external name RegExp.RegExp.RegExIsMatch;

go



-- 验证字符串是否以 [server] 开头

-- select dbo.regex_ismatch('[server].[database].[schema].[object]','^\[server\]');



if object_id('dbo.regex_replace','FS') is not null

 drop function dbo.regex_replace;

go

create function dbo.regex_replace

(@expression nvarchar(max), @pattern nvarchar(max), @replacement nvarchar(max))

returns nvarchar(max) with returns null on null input

as external name RegExp.RegExp.RegExReplace;

go



-- 将字符串中 [...] 替换为 "..."

-- select dbo.regex_replace('[server].[database].[schema].[object]','\[([\w]*)\]','"$1"');



if object_id('dbo.regex_substring','FS') is not null

 drop function dbo.regex_substring;

go

create function dbo.regex_substring

(@expression nvarchar(max), @pattern nvarchar(max), @position int, @occurrence int)

returns nvarchar(max) with returns null on null input

as external name RegExp.RegExp.RegExSubstring;

go



-- 提取字符串中与 [...] 模式匹配的第二次出现的字符串

-- select dbo.regex_substring('[server].[database].[schema].[object]','\[\w*\]',1,2);



if object_id('dbo.regex_count','FS') is not null

 drop function dbo.regex_count;

go

create function dbo.regex_count

(@expression nvarchar(max), @pattern nvarchar(max), @position int)

returns int with returns null on null input

as external name RegExp.RegExp.RegExCount;

go



-- 计算字符串中与 [...] 模式匹配的字符串的数目

-- select dbo.regex_count('[server].[database].[schema].[object]','\[\w*\]',1);



if object_id('dbo.regex_index','FS') is not null

 drop function dbo.regex_index;

go

create function dbo.regex_index

(@expression nvarchar(max), @pattern nvarchar(max), @position int, @occurrence int)

returns int with returns null on null input

as external name RegExp.RegExp.RegExIndex;

go



-- 查询字符串中与 [...] 模式匹配的第二次出现的字符串开始的位置

-- select dbo.regex_index('[server].[database].[schema].[object]','\[\w*\]',1,2);