Question

我正在使用c ++ PostgreSQL libpqxx库，我不知道为什么我无法打开事务/非事务对象。

我的代码目前如下

#include <iostream>
#include <pqxx/pqxx>

using namespace std;
using namespace pqxx;

int main() {

   // define variables
   string params;
   connection* pgsql;
   string sql;

   // db connection parameters
   params = "dbname=dummy user=postgres password=postgres hostaddr=10.10.0.2 port=5431";

   try {
      // make connection
      pgsql = new connection(params);
   } catch(const exception &log) {
      // connection failed
      cerr << log.what() << endl;
   }

   // prepare sql
   sql = " select * from categories where cat_idno = $1 ";
   pgsql->prepare("categories", sql)("integer");

   // execute transaction
   // this bit doesn't work
   work tr(pgsql);
   result row = tr.prepared("categories")(1).exec();
   tr.commit();

   // disconnect
   pgsql->disconnect();

}

它正好连接数据库并准备我的sql也没问题但是编译失败（我在CentOS 5上编译顺便说一句）

g++ -o ./pgsqltest ./pgsqltest02.cpp -lpqxx

给我以下错误

./pgsqltest02.cpp: In function ‘int main()’:
./pgsqltest02.cpp:24: error: no matching function for call to ‘pqxx::transaction<read_committed, read_write>::transaction(pqxx::connection*&)’
/usr/include/pqxx/transaction.hxx:102: note: candidates are: pqxx::transaction<ISOLATIONLEVEL, READWRITE>::transaction(pqxx::connection_base&) [with pqxx::isolation_level ISOLATIONLEVEL = read_committed, pqxx::readwrite_policy READWRITE = read_write]
/usr/include/pqxx/transaction.hxx:97: note: pqxx::transaction<ISOLATIONLEVEL, READWRITE>::transaction(pqxx::connection_base&, const std::string&) [with pqxx::isolation_level ISOLATIONLEVEL = read_committed, pqxx::readwrite_policy READWRITE = read_write]
/usr/include/pqxx/transaction.hxx:87: note: pqxx::transaction<read_committed, read_write>::transaction(const pqxx::transaction<read_committed, read_write>&)

我不确定为什么会这样，也许我错过了一些非常明显的事情

Answer 1

错误与编译命令有关，它需要指向libpqxx头文件和二进制文件的其他参数。正确的编译命令是

g++ -o ./pgsqltest ./pgsqltest02.cpp -I /opt/libpqxx/include -L /opt/libpqxx/lib -lpq -lpqxx

C ++ pqxx工作事务崩溃

1 个答案: