Connecting to a data source using OLE DB

The following describes how to use OLE DB interfaces to establish a connection to an Adaptive Server database.

There are two ways to set up a connection using OLE DB, described as follows:

1. Call CoCreateInstance.

2. Pass the clsid obtained from CLSIDFromProgID("ASEOLEDB").

3. Set the connection properties using IDBInitialize.

1. Call CoCreateInstance.

2. Pass the clsid obtained from MSDAINITIALIZE.

3. Set the connection properties using IDataInitialize.

A code example for establishing an OLE DB connection follows:

wchar_t* szInitializationString = L"Provider=ASEOLEDB;
   User ID=sa;Password=;Initial Catalog=pubs2;
   Data Source=MANGO:5000;"

IDataInitialize* pIDataInitialize = NULL;
HRESULT hr = CoCreateInstance(
     __uuidof(MSDAINITIALIZE), NULL, CLSCTX_ALL,
     __uuidof(IDataInitialize), (void**)&pIDataInitialize);

IDBInitialize* pIDBInitialize = NULL;
hr = pIDataInitialize->GetDataSource(NULL, CLSCTX_ALL,
     szInitializationString,
     __uuidof(IDBInitialize), (IUnknown**)&pIDBInitialize);
hr = pIDBInitialize->Initialize();

IDBCreateSession* pIDBCreateSession = NULL;
hr = pIDBInitialize->QueryInterface(
     IID_IDBCreateSession, (void**)&pIDBCreateSession);

IDBCreateCommand* pIDBCreateCommand = NULL;
hr = pIDBCreateSession->CreateSession(NULL,
     IID_IDBCreateCommand,
     (IUnknown**)&pIDBCreateCommand);

ICommandText* pICommandText = NULL;
hr = pIDBCreateCommand->CreateCommand(NULL,
     IID_ICommandText, (IUnknown**)&pICommandText);

// use the command object
// ...

pICommandText->Release();

pIDBCreateSession->Release();
pIDBCreateCommand->Release();
pIDBInitialize->Release();
pIDataInitialize->Release();