那些
ETL
E（Data Extraction）
擷取各類型態的資料，視其需要之程度設定不同抓取之頻率。
T（Data Transformation）
從各個不同來源所擷取的資料，必須根據特殊規則轉換其值 。
L（Data Load）
將擷取、轉換及清理過之資料正確的載入資料倉儲中。
Fact Table
中心資料表，包含數字量值 (Numerical Measure) 以及與維度資料表相關事實的索引鍵。
Key Column(s) - Foreign Key，對應 Dimension Primary Key
Measure Column(s) – 純數值欄位（Number or Float）
Like Transaction Table
Dimension Table
有組織的分類 (或層級) 階層架構，用來描述事實資料表 (Fact Table) 內的資料。
Key Column– Primary Key
Description Column– 描述Dimension 欄位之資料
Like Basic Table
Star Schema
每一個維度資料表經由索引鍵資料行，與事實資料表(Fact Table)直接地產生關聯 。
Snowflake Schema
Star Schema 的延伸，只有主要維度資料表聯結到事實資料表 。其他的維度資料表則聯結到主要維度資料表。
Denormalize（反正規化 ）
透過簡化資料倉儲結構描述 (Data Warehouse Schema) 的複雜性，來改善效率與執行效能。
Content Minimize
DW 容量成長快速，若非必要資料則勿轉入至DW內。
declare @a table (a int)
declare @i int
set @i=1
while(@i<=50)
begin
insert @a select @i
set @i=@i+1
end
select * from @a a,@a b,@a c,@a d,@a e
where
a.a>b.a and a.a>c.a and a.a>d.a and a.a>e.a
and b.a>c.a and b.a>d.a and b.a>e.a
and c.a>d.a and c.a>e.a
and d.a>e.a
and a.a+b.a+c.a+d.a+e.a=100
public class M {
int[] s = new int[50];
int count = s.length;
int[] sign = new int[count];
int mark[] = { 1, 0 };
int total = 0;
int onjNum = 100;
int fno = 0;
public static void main(String[] args){
Calendar cstart = Calendar.getInstance();
M g = new M();
g.calculate();
Calendar cend = Calendar.getInstance();
System.out.println("take time:" + (cend.getTimeInMillis() - cstart.getTimeInMillis()) / 1000.0 + " seconds");
}
public void calculate(){
for (int i = 0; i < count; i++) {
s[i] = i + 1;
sign[i] = 0;
}
total = 0;
f(0);
}
int ppp = 0;
private void f(int n){
if (n == count) {
return;
}
for (int i = 0; i < mark.length; i++) {
sign[n] = mark[i];
if (mark[i] == 1) {
total += s[n];
ppp++;
if (total == onjNum && ppp == 5) {
fno++;
show();
}
}
if (total < onjNum && ppp < 5)
f(n + 1);
if (mark[i] == 1) {
total -= s[n];
ppp--;
}
}
}
void show(){
StringBuffer buf = new StringBuffer();
for (int L = 0; L < s.length; L++)
if (sign[L] == 1)
buf.append(s[L] + " ");
System.out.println("no " + fno + ":" + buf.toString());
}
}
思路:
第一个数不能大于100 / 5
第二个数不能大于100 - 第一个数 / 4
类推
算法:(asp 低级吧)
nTotal = 100
nCount = 5
i = 0
For n1 = 1 To Int( nTotal / nCount )
If n1 > Int( nTotal / 2 ) Then Exit For
For n2 = n1 + 1 To Int( ( nTotal - n1 ) / ( nCount - 1 ) )
If n2 > Int( nTotal / 2 ) Then Exit For
For n3 = n2 + 1 To Int( ( nTotal - n1 - n2 ) / ( nCount - 2) )
If n3 > Int( nTotal / 2 ) Then Exit For
For n4 = n3 + 1 To Int( ( nTotal - n1 - n2 - n3 ) / ( nCount - 3 ) )
If n4 > Int( nTotal / 2 ) Then Exit For
For n5 = n4 + 1 To Int( ( nTotal - n1 - n2 - n3 - n4 ) / ( nCount - 4 ) )
If n5 > Int( nTotal / 2 ) Then Exit For
If n1 + n2 + n3 + n4 + n5 = nTotal Then
Response.Write n1 & "+" & n2 & "+" & n3 & "+" & n4 & "+" & n5 & "=" & nTotal & "<br/>"
i = i + 1
End If
Next
Next
Next
Next
Next
Response.Write i & "次"
--------
<html>
<head>
<script Language="JavaScript">
function mycalc()
{
// JmLei 2007.02.27
// jmlei.blogchina.com
var cnt=0;
var i=0;
var j=0;
var k=0;
var l=0;
var m=0;
var now = new Date();
var hh = now.getHours();
var mm = now.getMinutes();
var ss = now.getTime() % 60000;
document.write("Start Time: "+hh+":"+mm+":"+ss+"<br>");
for (i=1;i<100/5+1;i++)
{
for (j=i+1;j<(100-i)/4+1;j++)
{
for (k=j+1;k<(100-i-j)/3+1;k++)
{
for (l=k+1;l<(100-i-j-k)/2+1;l++)
{
for (m=l+1;m<51;m++)
{
if (i+j+k+l+m==100)
{
cnt=cnt+1;
// document.write("No."+cnt+" "+i+"+"+j+"+"+k+"+"+l+"+"+m+"=100<br>");
}
}
}
}
}
}
document.write("counter: "+cnt+"<br>");
now = new Date();
hh = now.getHours();
mm = now.getMinutes();
ss = now.getTime() % 60000;
document.write("End Time: "+hh+":"+mm+":"+ss+"<br>");
}
</script>
<body>
<Form>
<Input type="button" Value="calc" onClick="mycalc()">
</Form>
</body>
</html>
9.
StreamReader sr = new StreamReader(strFilePath,System.Text.Encoding.GetEncoding("utf-8"));
sr.BaseStream.Seek(0,SeekOrigin.Begin);
string strRead="";
while(sr.Peek()>-1)
{
strRead = sr.ReadLine();
DataRow Drow = ds.Tables[0].NewRow();
Drow[0] = strRead.Trim();
ds.Tables[0].Rows.Add(Drow);
}
sr.Close();
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