C++连接postgresql数据库 插入变量中的值

/*
 * db.cpp
 *
 *  Created on: Mar 7, 2018
 *      Author: zlf
 */


#include 
#include 
#include 
#include 

using namespace std;
using namespace pqxx;

int main(int argc, char* argv[]) {

	try {

		connection C(
				"dbname=hello user=postgres password=123 \
      hostaddr=127.0.0.1 port=5432");
		if (C.is_open()) {
			cout << "Opened database successfully: " << C.dbname() << endl;
		} else {
			cout << "Can't open database" << endl;
			return 1;
		}
		/* Create SQL statement */

		string patient_id = "A00001";

		string sql1 = "insert into diagnosis5 (patient_id, visit_number) "
				"VALUES('" + patient_id + "', '123456');";
		char sql[200];
		strcpy(sql, sql1.c_str());

		/* Create a transactional object. */
		work W(C);

		/* Execute SQL query */
		W.exec(sql);
		W.commit();
		cout << "Records created successfully" << endl;
		C.disconnect();

	} catch (const std::exception &e) {
		cerr << e.what() << std::endl;
		return 1;
	}

	return 0;
}