private static extern short SQLSetEnvAttr(IntPtr henv, int attribute, IntPtr valuePtr, int strLength);

            if (SQL_SUCCESS == SQLSetEnvAttr(henv, SQL_ATTR_ODBC_VERSION, (IntPtr)SQL_OV_ODBC3, 0))

            SQLSetEnvAttr(environmentHandle.ToInt32(), SQL_ATTR_ODBC_VERSION, new IntPtr(SQL_OV_ODBC3), 0);

You must provide an Environment Handle provided by SQLAllocHandle as the first parameter. SQLAllocHandle is a replacement for SQLAllocEnv. When using SQLAllocHandle, you must call SQLSetEnvAttr and set the SQL_ATTR_ODBC_VERSION attribute to SQL_OV_ODBC3 before calling SQLDataSources. You must release Environment handle with SQLFreeHandle at the end.

    rc = SQLSetEnvAttr(sql_env_handle, SQL_ATTR_ODBC_VERSION, (IntPtr)SQL_OV_ODBC3, 0);

static extern short SQLSetEnvAttr (

static extern short SQLSetEnvAttr (

Private Declare Auto Function SQLSetEnvAttr Lib "odbc32.dll" ( _