VC ++ calls the ADO troubleshooting notes

1. When connecting to an Access database with a password through ado, the following error is reported: "The workgroup information file is lost or has been opened exclusively by other users". For more information, see the information provided on the Internet, changed the connection string to "provider = Microsoft. jet. oledb.4.0; Data Source = database. MDB; persist Security info = false; Jet oledb: Database Password = 68984 ", but the database still cannot be connected. Later, I finally found myself adding myself. When the Database Password is specified in the connection string, the connection function does not need to provide the user name and password any more. // Set struid and strpwd to an empty string.
M_piconn-> open (_ bstr_t (strdb), _ bstr_t (struid), _ bstr_t (strpwd),-1 );
2. The database is connected, and the data query is successful. Even after the method is returned, a read/write conflict exception is thrown, and the exception is unknown, the error occurs in comip. A segment in H Code: Void _ release () Throw ()
{
If (m_pinterface! = NULL ){
M_pinterface-> release ();
}
} The _ recordsetptr and _ connectionptr com pointers both have the release method to release resources, at first, I thought I had an error releasing the resource when calling the release methods of the two pointers. Then I finally understood, originally, both com pointers use smart pointers encapsulated by _ com_smartptr_typedef. One feature of smart pointers is that resources can be automatically released. Now I understand, so I will cancel the place where the release method is explicitly called and let com manage resources by itself.