数据库.txt

vc使用技巧汇集

1.  通过SQL语句来完成日期区间的查询
str="select * from USER where LASTLOGIN>#2003-6-24#";  
str="select * from USER where LASTLOGIN>#2003-6-25 19:46:44#";  
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2.  ADO操作数据库表，更新出现问题  
在打开数据库前，添加如下语句试一下
pRecordSet->CursorLocation = adUseClient;
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3.  ADO取纪录字段值方式之一  
_variant_t  TheValue;  //VARIANT数据类型  
TheValue  =  m_pRecordset->GetCollect("BIG_NAME");//得到字段BIG_NAME的值  
if(TheValue.vt!=VT_NULL)  
   m_List.AddString((char*)_bstr_t(TheValue));  
   //将该值加入到列表控件中  
         
     //取纪录字段值方式之二  
  _bstr_t  TheValue1=m_pRecordset->Fields->GetItem("BIG_NAME")->Value;  
  CString  temp=TheValue1.copy();  
  m_List.AddString(temp);  
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4.   odbc遍历求数据库中表名：  
bool  CDBInfoDlg::ListTables(bool  bViews,  bool  bSystemTables)  
{  
           CDatabase database;  
           CString type = "'TABLE'";  
           int  ret= -1;  
           HSTMT hStmt;  
           UCHAR szName[256];  
           SDWORD cbName;  
           CString names;   
           if(  bViews  )  
               type  +=  ",  'VIEW'";//视图  
           if(  bSystemTables  )  
               type  +=  ",  'SYSTEM  TABLE'";//系统表   
           try{  
               if(  !database.Open(m_strDSN)  )  
                   return  false;  
           }  
           catch(...)
           {  
               AfxMessageBox("Unable  To  Obtain  Table  Information");  
               return  false;  
           }  
           SQLAllocStmt(database.m_hdbc,&hStmt);  
           ret  =  SQLTables(hStmt, NULL,SQL_NTS,  
                             NULL,SQL_NTS,  
                             NULL,SQL_NTS,  
                             (unsigned  char  *)type.GetBuffer(0),SQL_NTS);   
           if(ret  ==  SQL_ERROR)
           {  
                SQLFreeStmt(hStmt,SQL_CLOSE);  
                database.Close();  
                if(ret == SQL_INVALID_HANDLE )
                {  
                     AfxMessageBox("Invalid  handle");  
                     return  false;  
                }  
                AfxMessageBox("Database  Could  Not  be  Open");  
                return  false;  
           }            
           m_cmbTables.ResetContent();          
           while(1){                        
               ret  =  SQLFetch(hStmt);  
               if(ret  ==  SQL_NO_DATA_FOUND)  
                     break;  
               ret  =  SQLGetData(hStmt,3,SQL_C_CHAR,szName,TABLE_NAME_LENGTH,                             &cbName);  
               names.Format("%s",szName);  
               m_cmbTables.AddString(names);  
           }  

           m_cmbTables.SetCurSel(0);  
             
           SQLFreeStmt(hStmt,SQL_CLOSE);  
           database.Close();  
             
                       ShowTable();  
 
           return  true;  
}  
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如何访问用IP地址表示的数据库
Provider = SQLOLEDB.1;Persist Security Info=False;User ID=sa;Initial Catalog = traffic;Data Source=10.119.56.18
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如何使用ADO访问Oracle数据库存储过程? 
http://www.xhstudio.net/show.asp?id=2185
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vc6支持access 2000
AfxGetModuleState()->m_dwVersion = 0x0601;
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[Oracle初始口令]
internal/oracle
sys/change_on_install
system/manager
scott/tiger

在SQL SERVER中select top 10 * from tablename,在ORACLE中该怎么表示？
SELECT * FROM A WHERE ROWNUM < 11 
那查询第四行到第9行的数据呢？
SELECT * FROM
(
SELECT * FROM A WHERE ROWNUM < 10
MINUS
SELECT * FROM A WHERE ROWNUM < 4
)