This article will introduce how, at the most basic level, SQL Server can be communicated with using C++ and Native code, rather than using the .NET Framework.
The code shown below follows through the basic process, defined in the general flowchart for ODBC Applications as seen on MSDN. This was created in VS2010.
Using this process, we connect to a server (a local copy of SQL Server, with AdventureWorks 2008 R2, and does a straightforward query against it to do a Row Count of the Person table.
1: // The bare basics to query SQL Server, using the Native Client, in C++
2: //
3: #include "stdafx.h"
4: #include <iostream>
5: using namespace std;
6:
7: #define _SQLNCLI_ODBC_
8: #include "sqlncli.h"
9: #include "sqlext.h"
10:
11: int _tmain(int argc, _TCHAR* argv[])
12: {
13: // Define Handles
14: SQLHANDLE hEnv, hDBCCount, hStmtCount;
15: SQLINTEGER iRowCount, iRowCountInd;
16:
17: char sConnString[120] = "Driver={SQL Server Native Client 10.0};Server=localhost;Database=AdventureWorks2008R2;Trusted_Connection=yes;";
18:
19: // Step 1 - Assigning an Environment Variable
20: SQLAllocHandle(SQL_HANDLE_ENV, SQL_NULL_HANDLE, &hEnv);
21:
22: // Step 1 - Declaring the use of ODBCv3
23: SQLSetEnvAttr(hEnv, SQL_ATTR_ODBC_VERSION, (SQLPOINTER) SQL_OV_ODBC3, 0);
24:
25: // Step 1 - Creating a Connection Handle
26: SQLAllocHandle(SQL_HANDLE_DBC, hEnv, &hDBCCount);
27:
28: // Step 1 - Setting Connection Attributes
29: SQLSetConnectAttr(hDBCCount, SQL_ATTR_AUTOCOMMIT, (SQLPOINTER) SQL_AUTOCOMMIT_OFF, SQL_IS_INTEGER);
30:
31: // Step 1 - Initiating the connection to SQL Server
32: SQLDriverConnect(hDBCCount, NULL, (SQLTCHAR *) sConnString, SQL_NTS, NULL, 0, NULL, SQL_DRIVER_NOPROMPT);
33:
34: // Step 2 - Creating a Handle for the Statement
35: SQLAllocHandle(SQL_HANDLE_STMT, hDBCCount, &hStmtCount);
36:
37: // Step 3 - Connecting to AdventureWorks2008R2
38: SQLExecDirect(hStmtCount, (SQLTCHAR *)"USE AdventureWorks2008R2;", SQL_NTS);
39: cout << "USE AdventureWorks2008R2;" << endl;
40:
41: // Step 3 - Executing Query against Person.Person table
42: SQLExecDirect(hStmtCount, (SQLCHAR *)"select count(1) from Person.Person;" , SQL_NTS);
43: cout << "select count(1) from Person.Person;" << endl;
44:
45: // Step 4a - Assigning a variable to the return column
46: SQLBindCol(hStmtCount, 1,SQL_C_ULONG, &iRowCount, 0, &iRowCountInd);
47:
48: // Step 4a - Retrieving the data from the return dataset
49: SQLFetch(hStmtCount);
50:
51: cout << "Rows = " << iRowCount << endl;
52:
53: // Step 4a - Remove the Cursor
54: SQLCloseCursor(hStmtCount);
55:
56: // Step 5 - Closing down and Cleaning up
57: SQLDisconnect(hDBCCount);
58: SQLFreeHandle(SQL_HANDLE_DBC,hDBCCount);
59: SQLFreeHandle(SQL_HANDLE_ENV, hEnv);
60:
61: return 0;
62: }
Over the coming weeks, I’ll be expanding on this to get better performance for more complex processes and going through what each of these sections to.
I hope you find these articles interesting.
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