dawei
我们新建一个DataBase project，然后建立一个UserDefinedFunctions,Code像这样:
<div class=”codetitle”><a style=”CURSOR: pointer” data=”47900″ class=”copybut” id=”copybut47900″ onclick=”doCopy(‘code47900’)”> 代码如下:<div class=”codebody” id=”code47900″>
1: ///
/// SQLs the array.
///
/// <param name=”str”>The STR.
/// <param name=”delimiter”>The delimiter.
///
/// 1/8/2010 2:41 PM author: v-pliu
[SqlFunction(Name = “CLR_Split”,
FillRowMethodName = “FillRow”,
TableDefinition = “id nvarchar(10)”)]
public static IEnumerable SqlArray(SqlString str,SqlChars delimiter)
{
if (delimiter.Length == 0)
return new string[1] { str.Value };
return str.Value.Split(delimiter[0]);
}
///
/// Fills the row.
///
/// <param name=”row”>The row.
/// <param name=”str”>The STR.
/// 1/8/2010 2:41 PM author: v-pliu
public static void FillRow(object row,out SqlString str)
{
str = new SqlString((string)row);
}
然后Bulid,Deploy一切OK后，在SSMS中执行以下测试T-sql:
<div class=”codetitle”><a style=”CURSOR: pointer” data=”39614″ class=”copybut” id=”copybut39614″ onclick=”doCopy(‘code39614’)”> 代码如下:<div class=”codebody” id=”code39614″>
DECLARE @array VARCHAR(max)
SET @array = ‘39,15,93,68,64,43,90,58,39,9,26,89,47,91,57,98,16,55,63,29,69,41,76,34,60,61,53,32,30,11,72,36,22,14,38,24,5,66,21,99,18,7,10,46,27,88,75,48,94,59,35,19,79,87,49,13,1,80,92,85,51’ SELECT id FROM dbo.CLR_Split(@array,’,’)
我们来看它的Client Statistic:
接着我们执行测试T-sql使用相同的array:
代码如下:DECLARE @array VARCHAR(max)
SET @array = ‘39,51’
SELECT item FROM strToTable(@array,’)
CTE实现的Split function的Client statistic:
通过对比，你可以发现CLR的performance略高于CTE方式，原因在于CLR方式有Cache功能，并且把一个复杂的运算放到程序里比DataBase里更加高效。
您还可以参考：
Author:Petter Liu
