Poco C++ with MS SQL using ODBC - c++

Question

I am trying to connect to the Microsoft SQL Server database with Poco C++ via ODBC. I have tried to find examples, but havent come across any.
I am simply trying to connect to my database with the following code
#include <iostream>
#include <string>
#include "Poco/Data/Session.h"
using namespace std;
using namespace Poco::Data;
int main()
{
cout << "Testing Poco C++ with MS SQL Server" << endl;
const string CONNECTION_STRING("DRIVER={SQL Server};Server=DESKTOP-32BKOVJ\\SQLEXPRESS;Database=Test2;User ID=sa;Password=IaSS1982;Trusted_Connection=yes;");
Session session("ODBC", CONNECTION_STRING);
return 0;
}
Every time I run this code, I get the following assertion failure:
Assertion violation: _connectors.end() != it [in file "src\SessionFactory.cpp", line 70]
How can I create a simple connection to the MS SQL Database using Poco C++ and ODBC and then print some records on the console?
I was referring to the article Poco ODBC and while SQL loop while trying to write this code.
Any help will be greatly appreciated.
Thank you

Answer 1

I am able to connect to my Microsoft SQL Server 2014 Database using Poco C++ library. Once you have the ODBC drivers installed which are a part of the Windows SDK, the following code should do all basic operations such as
- Create
- Read
- Update
- Delete
#include <iostream>
#include <string>
#include <sstream>
#include "Poco/Data/RecordSet.h"
#include "Poco/Data/Session.h"
#include "Poco/Data/ODBC/Connector.h"
using namespace std;
using namespace Poco::Data;
bool AddUser(Session& session, const size_t& USER_ID, const string& FIRST_NAME, const string& LAST_NAME); // [C]reate
void PrintUsers(Session& session); // [R]etrieve
bool UpdateLastName(Session& session, const string& FIRST_NAME, const string& NEW_LAST_NAME); // [U]pdate
bool DeleteUser(Session& session, const size_t& USER_ID); // [D]elete
int main()
{
try
{
cout << "Testing Poco C++ with MS SQL Server" << endl;
Poco::Data::ODBC::Connector::registerConnector();
const string CONNECTION_STRING("DRIVER={SQL Server};Server=DESKTOP-32BKOVJ\\SQLEXPRESS;Database=Test2;User ID=sa;Password=abc");
//const string CONNECTION_STRING("DSN=PocoMsSQLTest;Uid=sa;Pwd=abc");
Session session("ODBC", CONNECTION_STRING);
if (session.isConnected())
{
PrintUsers(session);
cout << "\n" << endl;
AddUser(session, 5, "Loki", "Moki");
PrintUsers(session);
cout << "\n" << endl;
UpdateLastName(session, "Loki", "Poki");
PrintUsers(session);
cout << "\n" << endl;
DeleteUser(session, 5);
PrintUsers(session);
cout << "\n" << endl;
}
else
{
cerr << "Session not able to connect" << endl;
}
}
catch (const exception& e)
{
cerr << "Exception: " << e.what() << endl;
}
////////////////////////////////////////////////////////
Poco::Data::ODBC::Connector::unregisterConnector();
return 0;
}
// Create
bool AddUser(Session& session, const size_t& USER_ID, const string& FIRST_NAME, const string& LAST_NAME)
{
Statement select(session);
stringstream ss;
ss << "INSERT INTO Users (UserID, FirstName, LastName) VALUES (";
ss << USER_ID << ", " << "\'" << FIRST_NAME << "\'" << ", " << "\'" << LAST_NAME << "\')";
const string& SQL = ss.str();
select << SQL;
return select.execute();
}
// Retrieve
void PrintUsers(Session& session)
{
Statement select(session);
select << "SELECT * FROM Users";
select.execute();
RecordSet rs(select);
bool more = rs.moveFirst();
if (more)
{
cout << rs.columnName(0) << "\t" << rs.columnName(1) << "\t" << rs.columnName(2) << endl;
}
while (more)
{
cout << rs[0].convert<string>() << "\t" << rs[1].convert<string>() << "\t\t" << rs[2].convert<string>() << endl;
more = rs.moveNext();
}
}
// Update
bool UpdateLastName(Session& session, const string& FIRST_NAME, const string& NEW_LAST_NAME)
{
Statement select(session);
stringstream ss;
ss << "UPDATE Users SET LastName=" << "\'" << NEW_LAST_NAME << "\'" << " WHERE FirstName=" << "\'" << FIRST_NAME << "\'";
const string& SQL = ss.str();
select << SQL;
return select.execute();
}
// Delete
bool DeleteUser(Session& session, const size_t& USER_ID)
{
Statement select(session);
stringstream ss;
ss << "DELETE FROM Users WHERE UserID = " << USER_ID;
const string& SQL = ss.str();
select << SQL;
return select.execute();
}
The CONNECTION_STRING that I am using is using the ODBC drivers directly to connect to the database. If you want to use a DSN to connect to the database then comment this CONNECTION_STRING and uncomment the one below.
I did a little bit of research on what is DSN and how to create it in Windows 10. My findings are given below.
What is a DSN?
See https://en.wikipedia.org/wiki/Data_source_name
Creating an ODBC Data Source Name (DSN)
1. Windows 10 search for ODBC
2. Click on Set up ODBC data sources (32-bit)
3. Under the tab "User DSN", click Add
Create New Data Source wizard will start.
4. Select SQL Server and click Finish
5. In the next window
- Give a name. This is the DSN
- Give description
- Click the drop down associated with Server
- Wait for a few seconds
- Databases on your computer or network will show
- Select the database server you want to connect to.
- Click Next
6. In the next window
- Select with SQL Server Authentication
- Enter your Login ID (Username) and Password for that database
- Click Next
7. In the next window
- Select "Change the default database to:" the database you want to connect.
- Click Next
8. In the next window you don't have to change anything just click Finish.
9. A new window appears which has all your DSN information.
10. To test the DSN connection click on "Test Data Source..."
- If everything is ok, a new window appears "TESTS COMPLETED SUCCUSSFULLY!"
- Click OK to exit the result window.
11. Click OK again finish the setup.
12. In the main Window under User Data Sources you will see your newly created DSN.
13. Click OK to exit.
Source: https://www.youtube.com/watch?v=ehVFtmhPwxs