IDBInitialize::Initialize

Initializes a data source object or enumerator.

HRESULT Initialize();

Parameters

None.

Return Code

S_OK

The method succeeded.

DB_S_ASYNCHRONOUS

The method has initiated asynchronous initialization of the data source object. The consumer can call IDBAsynchStatus::GetStatus to poll for status or can register for notifications of asynchronous processing. Until asynchronous processing completes, the data source object remains in an uninitialized state.

DB_S_ASYNCHRONOUS should be returned before DB_S_ERRORSOCCURRED.

DB_S_ERRORSOCCURRED

The data source object or enumerator was initialized, but one or more properties—for which the dwOptions element of the DBPROP structure was DBPROPOPTIONS_OPTIONAL—were not set. To return properties in error, the provider uses DBPROPSET_PROPERTIESINERROR as described in Chapter 14: Properties. The method can fail to set properties for a number of reasons, including the following:

It was not possible to set the property.
The value in vValue in the DBPROP structure was invalid.
The property's value conflicted with an existing property.
DB_S_ASYNCHRONOUS should be returned before DB_S_ERRORSOCCURRED. Once rowset population is complete, the consumer can see DB_S_ERRORSOCCURRED either by calling IDBAsynchStatus::GetStatus or by receiving IDBAsynchNotify::OnStop.

E_FAIL

A provider-specific error occurred.

E_OUTOFMEMORY

The provider was unable to allocate sufficient memory to initialize the data source object or enumerator.

E_UNEXPECTED

The data source object is in the process of being initialized asynchronously. To cancel asynchronous execution, call IDBAsynchStatus::Abort.

DB_E_ALREADYINITIALIZED

IDBInitialize::Initialize had already been called for the data source object or enumerator, and an intervening call to IDBInitialize::Uninitialize had not been made.

DB_E_CANCELED

The provider prompted for additional information and the user selected Cancel.

DB_E_ERRORSOCCURRED

It was not possible to set the property.
The value in vValue in the DBPROP structure was invalid.
The property's value conflicted with an existing property.

DB_SEC_E_AUTH_FAILED

Authentication of the consumer to the data source object or enumerator failed. The data source object or enumerator remains in the uninitialized state.

Comments

IDBInitialize::Initialize initializes the data source object or enumerator. It uses the values of properties in the Initialization property group that have been set with IDBProperties::SetProperties. If the consumer has not set values for all required properties, IDBInitialize::Initialize can prompt for values.

If IDBInitialize::Initialize returns DB_S_ERRORSOCCURRED or DB_E_ERRORSOCCURRED, the consumer can immediately call IDBProperties::GetProperties with the DBPPROPSET_PROPERTIESINERROR property set to return the properties that could not be set. For more information, see "Property Sets" in Appendix C: OLE DB Properties.

For information about what the consumer can and cannot do with a data source object or enumerator before it is initialized, see "Data Source Object States" and "Enumerator States" in Chapter 2: Data Source and Session Objects.

Initializing a Data Source Object Through a Network Connection

The following shows how to instantiate a data source object as an in-process object using CoCreateInstance.

#include <oledb.h>
extern CLSID CLSID_DSO;
int main() {
   HRESULT           hr;
   IDBInitialize *   pIDBInitialize;

   // Create the data source object.
   hr = CoCreateInstance(CLSID_DSO, NULL,
                         CLSCTX_INPROC_SERVER,
                         IID_IDBInitialize, (void**)
                         &pIDBInitialize);

   // Set the initialization properties.
   DBPROP rgProps[8];
   for (ULONG i = 0; i <= 7; i++) {
      VariantInit(&rgProps[i].vValue);
      rgProps[i].dwOptions = DBPROPOPTIONS_REQUIRED;
   };

   rgProps[0].dwPropertyID = DBPROP_INIT_LOCATION;
   V_VT(&(rgProps[0].vValue)) = VT_BSTR;
   V_BSTR(&(rgProps[0].vValue)) =
          SysAllocStringLen(OLESTR("server"),
          wcslen(OLESTR("server")));

   rgProps[1].dwPropertyID = DBPROP_INIT_DATASOURCE;
   V_VT(&(rgProps[1].vValue)) = VT_BSTR;
   V_BSTR(&(rgProps[1].vValue)) =
          SysAllocStringLen(OLESTR("database"),
          wcslen(OLESTR("database")));

   rgProps[2].dwPropertyID = DBPROP_AUTH_PASSWORD;
   V_VT(&(rgProps[2].vValue)) = VT_BSTR;
   V_BSTR(rgProps[2].vValue) = SysAllocStringLen(OLESTR("password"),
                  wcslen(OLESTR("password")));

   rgProps[3].dwPropertyID = DBPROP_AUTH_USERID;
   V_VT(&(rgProps[3].vValue)) = VT_BSTR;
   V_BSTR(&(rgProps[3].vValue)) =
          SysAllocStringLen(OLESTR("username"),
          wcslen(OLESTR("username")));

   rgProps[4].dwPropertyID =
      DBPROP_AUTH_ENCRYPT_PASSWORD;
   V_VT(&(rgProps[4].vValue)) = VT_BOOL;
   V_BOOL(&(rgProps[4].vValue)) = VARIANT_TRUE;

   rgProps[5].dwPropertyID = DBPROP_AUTH_CACHE_AUTHINFO;
   V_VT(&(rgProps[5].vValue)) = VT_BOOL;
   V_BOOL(&(rgProps[5].vValue)) = VARIANT_TRUE;

   rgProps[6].dwPropertyID =
      DBPROP_AUTH_PERSIST_SENSITIVE_AUTHINFO;
   V_VT(&(rgProps[6].vValue)) = VT_BOOL;
   V_BOOL(&(rgProps[6].vValue)) = VARIANT_TRUE;

   rgProps[7].dwPropertyID =
      DBPROP_AUTH_PERSIST_ENCRYPTED;
   V_VT(&(rgProps[7].vValue)) = VT_BOOL;
   V_BOOL(&(rgProps[7].vValue)) = VARIANT_TRUE;

   // Create the structure containing the properties.
   DBPROPSET PropSet;
   PropSet.rgProperties      = rgProps;
   PropSet.cProperties       = 8;
   PropSet.guidPropertySet   = DBPROPSET_DBINIT;

   // Get an IDBProperties pointer and set the
   // initialization properties.
   IDBProperties *pIDBProperties;
   pIDBInitialize->QueryInterface(IID_IDBProperties,
                                  (void**)&pIDBProperties);
   pIDBProperties->SetProperties(1, &PropSet);
   pIDBProperties->Release();

   // Initialize the data source object.
   hr = pIDBInitialize->Initialize();
   pIDBInitialize->Release();
   return hr;
};