C# ¶ÁÈ¡ºÍдÈëoracleµÄblob×ֶεķ½·¨
//ÏòÊý¾Ý¿âÖÐдÈë
private void button1_Click(object sender, EventArgs e)
{
oracleConnection1.Open();
OracleCommand cmd = new OracleCommand("UPDATE TEST SET F2 =:blob where F1=:sn ", oracleConnection1);
cmd.Parameters.Add(new OracleParameter("blob",OracleType.Blob));
cmd.Parameters.Add(new OracleParameter("sn",OracleType.Int32));
FileInfo fi = new FileInfo("c:\\dos.doc");
FileStream fs = fi.OpenRead();
byte[] MyData = new byte[fs.Length];
fs.Read(MyData, 0, System.Convert.ToInt32(fs.Length));
fs.Close();
cmd.Parameters["blob"].Value = MyData;
cmd.Parameters["sn"].Value = 1;
try
{
int result = cmd.ExecuteNonQuery();
if (result < 1)
 
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using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Data.SqlC ......
1. ASCII
·µ»ØÓëÖ¸¶¨µÄ×Ö·û¶ÔÓ¦µÄÊ®½øÖÆÊý;
SQL> select ascii(A) A,ascii(a) a,ascii(0) zero,ascii( ) space from dual;
A A ZERO SPACE
--------- --------- --------- ---------
65 97 48 32
2. CHR
¸ø³öÕûÊý,·µ»Ø¶ÔÓ¦µÄ×Ö·û;
SQL> select chr(54740) zhao,chr(65) chr65 from dual;
ZH C
-- ......
Ò».ÎïÀí¶Á(physical read)
µ±Êý¾Ý¿éµÚÒ»´Î¶ÁÈ¡µ½,¾Í»á»º´æµ½buffer cache ÖÐ,¶øµÚ¶þ´Î¶ÁÈ¡ºÍÐ޸ĸÃÊý¾Ý¿éʱ¾ÍÔÚÄÚ´æbuffer cache ÁË ÒÔÏÂÊÇÀý×Ó:
1.1 µÚÒ»´Î¶ÁÈ¡:
C:"Documents and Settings"Paul Yi>sqlplus "/as sysdba"
SQL*Plus: Release 9.2.0.4.0 - Production on Thu Feb 28 09:32:04 2008
Copyright (c) 19 ......
oracleµÄnvlº¯ÊýµÄÓ÷¨ ͨ¹ý²éѯ»ñµÃij¸ö×ֶεĺϼÆÖµ£¬Èç¹ûÕâ¸öֵλnull½«¸ø³öÒ»¸öÔ¤ÉèµÄĬÈÏÖµ
select nvl(sum(t.dwxhl),1) from tb_jhde t where zydm=-1ÕâÀï¹ØÐĵÄnvlµÄÓ÷¨£¬nvl£¨arg,value£©´ú±íÈç¹ûÇ°ÃæµÄargµÄֵΪnullÄÇô·µ»ØµÄֵΪºóÃæµÄvalue
Èç: NVL(a,b)¾ÍÊÇÅжÏaÊÇ·ñÊÇNULL,Èç¹û²»ÊÇ·µ»ØaµÄÖµ£¬Èç¹ ......
ORACLE ʱ¼ä×Ö¶ÎÅÅÐòÎÊÌâ
ÔçÉÏÔÚŪEXTÅÅÐòµÄʱºò£¬ÒòΪÊý¾Ý¿âIDÊÇSTRINGµÄ£¬Òò´ËÔÚcommandÀàÀï¶àÁËÒ»¸öinteger idSort×ֶΣ¬
ûÏëµ½£¬¸ù¾ÝÕâ¸öÕûÐ͵Ä×ֶνøÐÐÅÅÐòÒ²²»ÐУ¬ÒòΪEXT·ÖÒ³³öÀ´µÄËäÈ»ÊǸù¾ÝÕâ¸öÕûÐÍ×Ö¶ÎÅÅÐòÁË¡£µ«ÊÇ
¸÷¸öÒ³ÃæÃ»ÓÐÍêÈ«µÄͳһÅÅÐò¡£
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select tbl from Tr ......