---
title: "SQL Server Express LocalDB Reference | Microsoft Docs"
ms.custom: ""
ms.date: "03/06/2017"
ms.prod: sql
ms.prod_service: "database-engine"
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ms.technology: 

ms.topic: "reference"
ms.assetid: 25b71829-bdb1-46f4-ac36-80ddced52f3d
author: "CarlRabeler"
ms.author: "carlrab"
manager: craigg
---
# SQL Server Express LocalDB Reference
[!INCLUDE[appliesto-ss-xxxx-xxxx-xxx-md](../includes/appliesto-ss-xxxx-xxxx-xxx-md.md)]
  This section contains information about the SQL Server Express LocalDB:  
  
-   [SQL Server Express LocalDB Error Message Reference](../relational-databases/express-localdb-error-messages/sql-server-express-localdb-reference-error-messages.md)  
  
-   [SQL Server Express LocalDB Instance API Reference](../relational-databases/express-localdb-instance-apis/sql-server-express-localdb-reference-instance-apis.md)  
  
## Code Sample  
 The following sample demonstrates the LocalDB API.  Make sure that LocalDB is installed on the computer before running this sample.  You can install LocalDB from setup in the [!INCLUDE[ssCurrent](../includes/sscurrent-md.md)] 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 sqlncli.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 "sqlncli.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();  
}  
```