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SQL2005CLR函数扩展-天气服务

news 来源：原创 2024/5/19 12:50:11

我们可以用CLR获取网络服务来显示到数据库自定函数的结果集中，比如163的天气预报

http://news.163.com/xml/weather.xml

他的这个xml结果的日期是不正确的，但这个我们暂不讨论。

从这个xml获取天气的CLR代码如下，用WebClient访问一下就可以了。然后通过Dom对象遍历节点属性返回给结果集。

using System;

using System.Data;

using System.Data.SqlClient;

using System.Data.SqlTypes;

using System.Collections;

using System.Collections.Generic;

using Microsoft.SqlServer.Server;

public partial class UserDefinedFunctions

{

[SqlFunction (TableDefinition = "city nvarchar(100),date nvarchar(100),general nvarchar(100),temperature nvarchar(100),wind nvarchar(100)" , Name = "GetWeather" , FillRowMethodName = "FillRow" )]

public static IEnumerable GetWeather()

{

System.Collections.Generic.List <Item > list = GetData();

return list;

}

public static void FillRow(Object obj, out SqlString city, out SqlString date, out SqlString general, out SqlString temperature, out SqlString wind)

{

Item data = (Item )obj;

city = data.city;

date = data.date;

general = data.general;

temperature = data.temperature;

wind = data.wind;

}

class Item

{

public string city;

public string date;

public string general;

public string temperature;

public string wind;

}

static System.Collections.Generic.List <Item > GetData()

{

System.Collections.Generic.List <Item > ret = new List <Item >();

//try

//{

string url = "http://news.163.com/xml/weather.xml" ;

System.Net.WebClient wb = new System.Net.WebClient ();

byte [] b = wb.DownloadData(url);

string data = System.Text.Encoding .Default.GetString(b);

System.Xml.XmlDocument doc = new System.Xml.XmlDocument ();

doc.LoadXml(data);

foreach (System.Xml.XmlNode node in doc.ChildNodes[1])

{

string city = GetXMLAttrib(node, "name" );

foreach (System.Xml.XmlNode subnode in node.ChildNodes)

{

Item item = new Item ();

item.city = city;

item.date = GetXMLAttrib(subnode, "date" );

item.general = GetXMLAttrib(subnode, "general" );

item.temperature = GetXMLAttrib(subnode, "temperature" );

item.wind = GetXMLAttrib(subnode, "wind" );

ret.Add(item);

}

//}

//catch(Exception ex)

//{

// SqlContext.Pipe.Send(ex.Message);

//}

return ret;

}

static string GetXMLAttrib(System.Xml.XmlNode node, string attrib)

{

try

{

return node.Attributes[attrib].Value;

}

catch

{

return string .Empty;

}

};

部署这个clr函数的脚本如下

drop function dbo. xfn_GetWeather

drop ASSEMBLY TestWeather

CREATE ASSEMBLY TestWeather FROM 'd:\sqlclr\TestWeather.dll' WITH PERMISSION_SET = UnSAFE;