Referência de LocalDB do SQL Server Express
Aplica-se a: SQL Server
Esta seção contém informações sobre o LocalDB do SQL Server Express:
Referência de mensagem de erro de LocalDB do SQL Server Express
Referência de API da instância de LocalDB do SQL Server Express
Exemplo de código
O exemplo a seguir demonstra a API LocalDB. Verifique se o LocalDB está instalado no computador antes de executar esse exemplo. Você pode instalar o LocalDB a partir da instalação no SQL Server Express.
// compile with: Advapi32.lib
#include <SDKDDKVer.h>
#include <stdio.h>
// To use LocalDB API, you must define LOCALDB_DEFINE_PROXY_FUNCTIONS before you include msoledbsql.h in one (and only one) of the
// source files in your program. LOCALDB_DEFINE_PROXY_FUNCTIONS causes code to be generated that binds to the LocalDB API at runtime.
#define LOCALDB_DEFINE_PROXY_FUNCTIONS
#include "msoledbsql.h"
HRESULT CreateAndStartLocalDBInstance(PWCHAR wszVersion, PWCHAR wszInstanceName) {
HRESULT hr;
if (SUCCEEDED(hr = LocalDBCreateInstance(wszVersion, wszInstanceName, 0)))
hr = LocalDBStartInstance(wszInstanceName, 0, NULL, NULL);
return hr;
}
HRESULT StopAndDeleteLocalDBInstance(PWCHAR wszInstanceName) {
HRESULT hr;
if (SUCCEEDED(hr = LocalDBStopInstance(wszInstanceName, 0, 30))) // 30 seconds timeout
hr = LocalDBDeleteInstance(wszInstanceName, 0);
return hr;
}
void PrintLocalDBError(HRESULT hr) {
HRESULT hrError;
WCHAR wszMessage[1024];
DWORD dwMessage = 1024;
if (hr == LOCALDB_ERROR_NOT_INSTALLED)
wprintf(L"Local DB is not installed.\n");
else if (hr == LOCALDB_ERROR_CANNOT_LOAD_RESOURCES)
wprintf(L"Cannot load resources for Local DB API DLL. Local DB installation is corrupted.\n");
else if (FAILED(hrError = LocalDBFormatMessage(hr, 0, 0, wszMessage, &dwMessage)))
wprintf(L"Cannot format an error message for a Local DB error code: %#x. LocalDBFormatMessage returned: %#x\n", hr, hrError);
else
wprintf(L"%s\n", wszMessage);
}
HRESULT PrintLocalDBInstances() {
HRESULT hr;
DWORD dwNumberOfInstances = 0;
if (FAILED(hr = LocalDBGetInstances(NULL, &dwNumberOfInstances)))
if (hr != LOCALDB_ERROR_INSUFFICIENT_BUFFER)
return hr;
PTLocalDBInstanceName localDBInstnces = (PTLocalDBInstanceName) malloc(dwNumberOfInstances * sizeof(TLocalDBInstanceName));
if (localDBInstnces == NULL) {
return HRESULT_FROM_WIN32(ERROR_OUTOFMEMORY);
}
if (FAILED(hr = LocalDBGetInstances(localDBInstnces, &dwNumberOfInstances))) {
free(localDBInstnces);
return hr;
}
for (DWORD i = 0; i < dwNumberOfInstances; i++) {
LocalDBInstanceInfo localDBInstanceInfo;
if (FAILED(hr = LocalDBGetInstanceInfo(localDBInstnces[i], &localDBInstanceInfo, sizeof(localDBInstanceInfo)))) {
free(localDBInstnces);
return hr;
}
wprintf(L"Name: %s State: %s Version: %u.%u.%u.%u\n",
localDBInstnces[i],
localDBInstanceInfo.bIsRunning ? L"running" : L"stopped",
localDBInstanceInfo.dwMajor,
localDBInstanceInfo.dwMinor,
localDBInstanceInfo.dwBuild,
localDBInstanceInfo.dwRevision);
}
free(localDBInstnces);
return S_OK;
}
int main() {
HRESULT hr;
WCHAR wszInstanceName[] = L"Contoso";
WCHAR wszVersion[] = L"11.0";
if (FAILED(hr = CreateAndStartLocalDBInstance(wszVersion, wszInstanceName)))
PrintLocalDBError(hr);
PrintLocalDBInstances();
if (FAILED(hr = StopAndDeleteLocalDBInstance(wszInstanceName)))
PrintLocalDBError(hr);
PrintLocalDBInstances();
}