提高你的数据库编程效率：Microsoft CLR Via Sql Server

你还在为数据库编程而抓狂吗？那些恶心的脚本拼接，低效的脚本调试的日子将会与我们越来越远啦。现在我们能用支持.NET的语言来开发数据库中的对象，如：存储过程，函数，触发器，集合函数已及复杂的类型。看到这些你还能淡定吗？哈哈，不仅仅是这些。那些能被.NET支持的第三方扩展通过该技术统统都能应用在数据库编程上，如：正则表达式，.NET庞大的加密解密库，以及各种.NET集成的排序和搜索算法。

下面我就来一一介绍怎么使用该技术来解放我们的双手！

实现存储过程

[csharp] view plaincopyprint?

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using Microsoft.SqlServer.Server;

using System.Data;

using System.Data.SqlClient;

using System.Data.SqlTypes;

using System.Collections;

public class SampleStoreProcedure

{

[SqlProcedure]

public static void PrintStudentDetail()

{

SqlConnection conn = new SqlConnection("Context connection=true");

conn.Open();

SqlCommand cmd = new SqlCommand("select * from student", conn);

SqlCommand cmd2 = new SqlCommand("insert into studentdetail values(@detail)");

SqlDataReader reader;

string tmpData=string.Empty;

ArrayList tmpDataArray=new ArrayList();

reader = cmd.ExecuteReader();

while (reader.Read())

{

for (int i = 0; i < reader.FieldCount; i++)

{

tmpData += reader[i].ToString();

}

tmpDataArray.Add(tmpData);

}

reader.Close();

cmd2.Connection = conn;

foreach (string tmp in tmpDataArray)

{

cmd2.Parameters.Clear();

cmd2.Parameters.AddWithValue("@detail", tmp);

cmd2.ExecuteNonQuery();

}

conn.Close();

//conn2.Close();

}

[SqlProcedure]

public static void GetStudentDetail(int id)

{

SqlConnection conn = new SqlConnection("Context connection=true");

SqlCommand cmd = new SqlCommand("select * from student where id=@id", conn);

SqlDataReader reader;

cmd.Parameters.AddWithValue("@id", id);

try

{

conn.Open();

reader = cmd.ExecuteReader();

SqlPipe pipe = SqlContext.Pipe;

pipe.Send(reader);

reader.Close();

}

catch

{

conn.Close();

}

finally

{

}

}

};

部署步骤

[sql] view plaincopyprint?

1.编译项目，获取生成的DLL文件。

2.在数据库中输入命令sp_configure [clr enabled],1 reconfigure --开启对程序集的信任权限。

3.输入命令:create assembly chapter34_UDT from 'c:\chapter34_UDT.dll' 注册程序集

4.输入命令：

<p>--注册存储过程

create procedure PrintStudentDetail

as

external name chapter34_UDT.SampleStoreProcedure.PrintStudentDetail</p><p>--注册带参数的存储过程

create procedure GetStudentDetail

(

@Id int

)

as

external name chapter34_UDT.SampleStoreProcedure.GetStudentDetail</p>

执行结果

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exec PrintStudentDetail

exec GetStudentDetail 1



存储过程PrintStudentDetail执行结果



存储过程GetStudentDetail执行的结果

实现函数

[csharp] view plaincopyprint?

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Data;

using System.Data.SqlClient;

using System.Data.SqlTypes;

using Microsoft.SqlServer.Server;

using System.Security;

using System.Security.Cryptography;

public class SampleFunction

{

public SampleFunction()

{

}

[SqlFunction]

public static SqlString Hash(SqlString data)

{

SHA1 sha1 = SHA1.Create();

byte[] tmp = Encoding.ASCII.GetBytes(data.Value);

string result= Convert.ToBase64String(sha1.ComputeHash(tmp));

return new SqlString(result);

}

}

部署步骤

[sql] view plaincopyprint?

1.编译项目，获取生成的DLL文件。

2.在数据库中输入命令：

sp_configure [clr enabled],1 reconfigure --开启对程序集的信任权限。

3.输入命令:

create assembly chapter34_UDT from 'c:\chapter34_UDT.dll' 注册程序集

--如果上述步骤已经做了就忽略

<p>4.输入命令：</p>

--注册函数

create function HashSomeThing(@data nvarchar) returns nvarchar

as

external name chapter34_UDT.SampleFunction.[Hash]

执行结果

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<p>输入调用命令:</p>select dbo.HashSomeThing(name) from Student

实现表值函数

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using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Data;

using System.Data.SqlClient;

using System.Data.SqlTypes;

using Microsoft.SqlServer.Server;

using System.Text.RegularExpressions;

using System.Xml.Linq;

using System.Xml;

using System.IO;

using System.Collections;

public class SampleTableValueFunction

{

///

/// 表值函数的主体，该函数需要结合“内容填充函数”才能发挥功能。这里的“内容填充函数”是通过

/// 属性“FillRowMethodName”属性来指定的。属性“TableDefinition”用来定义返回表格的格式。

///

[SqlFunction(TableDefinition = "tmp_value nvarchar(max)", FillRowMethodName = "FillRow")]

public static IEnumerable PrintOneToTen()

{

IList<string> result2 = new List<string>();

var matches = new string[]{

"one",

"two",

"three",

"four",

"five",

"six",

"seven",

"eight",

"nine",

"ten"

};

return matches.AsEnumerable();

}

public static void FillRow(object obj, out SqlString tmp)

{

tmp = new SqlString(obj.ToString());

}

}

部署步骤

[sql] view plaincopyprint?

1.编译项目，获取生成的DLL文件。

2.在数据库中输入命令：

sp_configure [clr enabled],1 reconfigure --开启对程序集的信任权限。

3.输入命令:

create assembly chapter34_UDT from 'c:\chapter34_UDT.dll' 注册程序集

--如果上述步骤已经做了就忽略

4.输入命令：

create function SampleTableValueFunction() returns table(tmp_value nvarchar(max) null)

as

external name chapter34_UDT.SampleTableValueFunction.PrintOneToTen

执行结果

实现触发器

[csharp] view plaincopyprint?

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using Microsoft.SqlServer.Server;

using System.Data;

using System.Data.SqlClient;

using System.Data.SqlTypes;

public class SampleTrigger

{

public SampleTrigger()

{

}

[SqlTrigger(Event = "For Insert,Update,Delete", Name = "PrintInfo", Target = "Student")]

public static void PrintInfo()

{

SqlTriggerContext triggerContext = SqlContext.TriggerContext;

SqlConnection conn = new SqlConnection("Context connection=true");

SqlCommand cmd = new SqlCommand();

cmd.Connection = conn;

switch (triggerContext.TriggerAction)

{

case TriggerAction.Insert:

cmd.CommandText = "insert into StudentDetail values('insert operation!')";

break;

case TriggerAction.Delete:

cmd.CommandText = "insert into StudentDetail values('delete operation!')";

break;

case TriggerAction.Update:

cmd.CommandText = "insert into StudentDetail values('update operation!')";

break;

default:

break;

}

try

{

conn.Open();

cmd.ExecuteNonQuery();

}

catch

{

}

finally

{

conn.Close();

}

}

[SqlTrigger(Name="InsertSomething",Target="chapter30.dbo.Student",Event="FOR INSERT")]

public static void InsertSomething()

{

SqlTriggerContext triggerContext = SqlContext.TriggerContext;

if (triggerContext.TriggerAction == TriggerAction.Insert)

{

var conn = new SqlConnection("Context connection=true");

var cmd = new SqlCommand();

cmd.Connection = conn;

cmd.CommandText = "Insert into StudentDetail values('insert event')";

conn.Open();

cmd.ExecuteNonQuery();

conn.Close();

}

}

}

部署步骤

[sql] view plaincopyprint?

1.编译项目，获取生成的DLL文件。

2.在数据库中输入命令：

sp_configure [clr enabled],1 reconfigure --开启对程序集的信任权限。

3.输入命令:

create assembly chapter34_UDT from 'c:\chapter34_UDT.dll' 注册程序集

--如果上述步骤已经做了就忽略

4.输入命令：

--注册触发器

create trigger PrintSomething on Student

for insert,update,delete

as

external name chapter34_UDT.SampleTrigger.PrintInfo

执行结果

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输入命令：

insert into Student values(12345,'tmp','11','11')

update Student set Name='new'+Name where Id=12345

delete from Student where Id=12345

select * from StudentDetail

实现聚合函数

[csharp] view plaincopyprint?

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using Microsoft.SqlServer.Server;

using System.Data;

using System.Data.SqlClient;

using System.Data.SqlTypes;

[Serializable]

[SqlUserDefinedAggregate(Format.Native)]

public struct SampleSum

{

private int sum;

public void Init()

{

sum = 0;

}

public void Accumulate(SqlInt32 Value)

{

sum += Value.Value;

}

public void Merge(SampleSum Group)

{

sum += Group.sum;

}

public SqlInt32 Terminate()

{

return new SqlInt32(sum);

}

}

部署步骤

[sql] view plaincopyprint?

1.编译项目，获取生成的DLL文件。

2.在数据库中输入命令：

sp_configure [clr enabled],1 reconfigure --开启对程序集的信任权限。

3.输入命令:

create assembly chapter34_UDT from 'c:\chapter34_UDT.dll' 注册程序集

--如果上述步骤已经做了就忽略

4.输入命令：

--注册聚合函数

create aggregate SampleSum(@value int) returns int

external name [chapter34_UDT].SampleSum

执行结果

[sql] view plaincopyprint?

输入命令：

select dbo.SampleSum(TAggregate) from TAggregate

select Sum(TAggregate) from TAggregate

实现类型

[csharp] view plaincopyprint?

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using Microsoft.SqlServer.Server;

using System.Data.SqlTypes;

using System.Data;

using System.Data.SqlClient;

[Serializable]

[Microsoft.SqlServer.Server.SqlUserDefinedType(Format.Native)]

public struct Facade : INullable

{

public bool isNull;

int hairColor;

int tall;

int skin;

int country;

public Facade(int hairColor, int tall, int skin, int country)

{

isNull = false;

this.hairColor = hairColor;

this.tall = tall;

this.skin = skin;

this.country = country;

}

public static Facade Null

{

get

{

return new Facade { isNull = true };

}

}

public override string ToString()

{

StringBuilder sb = new StringBuilder();

sb.AppendFormat("{0};", hairColor);

sb.AppendFormat("{0};", tall);

sb.AppendFormat("{0};", skin);

sb.AppendFormat("{0}", country);

return sb.ToString();

}

public static Facade Parse(SqlString data)

{

if (data.IsNull)

{

return new Facade { isNull = true };

}

Facade result;

string[] tmpData = data.Value.Split(';');

result = new Facade(int.Parse(tmpData[0]), int.Parse(tmpData[1]), int.Parse(tmpData[2]), int.Parse(tmpData[3]));

return result;

}

public bool IsNull

{

get { return isNull; }

}

}

部署步骤

[sql] view plaincopyprint?

1.编译项目，获取生成的DLL文件。

2.在数据库中输入命令：

sp_configure [clr enabled],1 reconfigure --开启对程序集的信任权限。

3.输入命令:

create assembly chapter34_UDT from 'c:\chapter34_UDT.dll' 注册程序集

--如果上述步骤已经做了就忽略

4.输入命令：

create type Facade external name

[chapter34_UDT].Facade

执行结果

小结

CLR Sql Server 的推出大大的提高了Sql Server的脚本编程效率问题，并且这项技术给了我们很大的相信空间。现在我们就来用有限的手段实现无限的可能吧！

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