在存储过程中调用外部的动态连接库
CREATE PROCEDURE sp_testdll AS
exec sp_addextendedproc 'SetFileName', 'storeproc.dll' --声明函数
exec sp_addextendedproc 'addLine', 'storeproc.dll'
declare @szFileName varchar(200)
declare @szText varchar(200)
declare @rt int
Select @szFileName = 'c:\welcome.txt'
EXEC @rt = SetFileName @szFileName --调用SetFileName函数,参数为--szFileName;
if @rt = 0
begin
select @szText = 'welcome 01'
Exec @rt = addLine @szText --调用addLine
select @szText = 'welcome 02'
Exec @rt = addLine @szText
end
exec sp_dropextendedproc 'SetFileName'
exec sp_dropextendedproc 'addLine'
dbcc SetFileName(free)
dbcc addLine(free)
动态连接库的实现:这种动态连接库和普通的有所不同。该动态连接库要放入SQL的执行目录下,或直接放到Window的System32目录下,并重起SQL-Server #include <windows.h>
#include <srv.h> //要加入这个.h文件
#define XP_NOERROR 0
#define XP_ERROR 1
#ifndef _DEBUG
#define _DEBUG
#endif
char szFileName[MAX_PATH+1];
void WriteInfo(const char * str);
extern "C" SRVRETCODE WINAPI SetFileName(SRV_PROC* pSrvProc)
{
WriteInfo("SetFileName start");
int paramCount = srv_rpcparams(pSrvProc);
if (paramCount != 1){
WriteInfo("Param Err start");
return XP_ERROR;
}
BYTE bType;
unsigned long cbMaxLen;
unsigned long cbActualLen;
BOOL fNull;
int ret = srv_paraminfo(pSrvProc, 1, &bType, &cbMaxLen, &cbActualLen,
NULL, &fNull);
if (cbActualLen){
ZeroMemory(szFileName, MAX_PATH+1);
memcpy(szFileName, srv_paramdata(pSrvProc, 1), cbActualLen);
WriteInfo("Set filename ok");
return (XP_NOERROR);
}
else {
WriteInfo("Set filename param failed");
return XP_ERROR;
}
}
extern "C" SRVRETCODE WINAPI addLine(SRV_PROC* pSrvProc)
{
WriteInfo("addline start");
int paramCount = srv_rpcparams(pSrvProc);
if (paramCount != 1){
WriteInfo("addline param err");
return XP_ERROR;
}
BYTE bType;
unsigned long cbMaxLen;
unsigned long cbActualLen;
BOOL fNull;
bool rt = false;
int ret = srv_paraminfo(pSrvProc, 1, &bType, &cbMaxLen, &cbActualLen,
NULL, &fNull);
if (cbActualLen){
int n;
char srt[3] = {0x0d, 0x0a, 0};
char * c = new char[cbActualLen + 3];
if (!c)return XP_ERROR;
ZeroMemory(c, cbActualLen + 3);
memcpy(c, srv_paramdata(pSrvProc, 1), cbActualLen);
memcpy(c+cbActualLen, srt, 3);
HANDLE hf = CreateFile(szFileName, GENERIC_WRITE, FILE_SHARE_WRITE|FILE_SHARE_READ, NULL,
OPEN_ALWAYS, 0, NULL);
if (hf == INVALID_HANDLE_VALUE){
WriteInfo("addline create file err ");
delete []c;
return XP_ERROR;
}
WriteInfo("addline create file ok ");
DWORD dwWt;
n = strlen(c);
SetFilePointer(hf, 0, NULL, FILE_END);
if (WriteFile(hf, c, n, &dwWt, NULL) && dwWt == n)
{
WriteInfo("addline write file ok ");
rt = true;
}
delete []c;
CloseHandle(hf);
}
return rt ? XP_NOERROR:XP_ERROR;
}
inline void WriteInfo(const char * str){
#ifdef _DEBUG
char srt[3] = {0x0d, 0x0a, 0};
HANDLE hf = CreateFile("c:\\storeproc.log", GENERIC_WRITE, FILE_SHARE_WRITE|FILE_SHARE_READ, NULL,
OPEN_ALWAYS, 0, NULL);
if (hf != INVALID_HANDLE_VALUE){
SetFilePointer(hf, 0, NULL, FILE_END);
DWORD dwWt;
WriteFile(hf, str, strlen(str), &dwWt, NULL);
WriteFile(hf, srt, strlen(srt), &dwWt, NULL);
CloseHandle(hf);
}
else {
MessageBox(NULL, "Write info err", "Message", MB_OK|MB_ICONINFORMATION);
}
#endif
}
BOOL WINAPI DllMain(HINSTANCE hinstDLL,DWORD fdwReason,LPVOID lpReserved)
{
return TRUE;
}
编译完成后,把动态链接库放到WINNT/System32目录下,启动SQL Server。我们可以打开SQL Server Query Analyzer调用存储过程sp_testdll以测试其运行是否正确。
具体可参考SQL-Server的在线帮助。
笔者环境:win2000 professional + SQL-Server7.0(2000也可)
VC6.0+SP5+Platform SDK 20001.8