postgres_util.h

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#ifndef __postgres_util_h
#define __postgres_util_h
#include "globals.h"
#include "libpq-fe.h"
#include "model.h"
#include <iomanip>
#include <iostream>
#include <vector>
#include <map>

class Hazy_Database {
 private:
  PGconn *conn;
  PGresult *res;
  void exit_nicely()
  {
    fprintf(stderr, "problem: %s", PQerrorMessage(conn));
    PQfinish(conn);
  }
  
 public:
  Hazy_Database(std::string dbname);
  int execute_statement_msg(const char* stmt, const char *msg);
  int execute_query_msg_text(const char* query, const char* msg, std::string &result);

  int execute_query_msg_double(const char* query, const char* msg, double &result);
  int execute_query_msg_int(const char* query, const char* msg, int &result);
  
  int copy_to_table(std::istream &s, std::string &table_name, std::string &delimiter);
  int copy_from_table(std::ostream &s, std::string &table_name, std::string &delimiter);
  
  template<class T>
    int postgresTupleParser(const char* szQuery, int (*tuple_parser)(PGresult *r, int index, T &out), std::vector<T> &_out)
    {
      res = PQexec(conn, szQuery);
      if (!res || (PQresultStatus(res) != PGRES_COMMAND_OK && PQresultStatus(res) != PGRES_TUPLES_OK))
        {
          fprintf(stderr, "PROBLEM %s: %s\n", "query error in postgresTupleParser", PQerrorMessage(conn));
          PQclear(res);
          this->exit_nicely();
          return -1;
        }
      int _n = PQntuples(res);
      for(int i = 0; i < _n; i ++) {
        T _t;
        if(tuple_parser(res, i, _t) < 0) {     
          fprintf(stderr, "tuple could not be parsed in postgresTupleParser method\n");
          return -1;
        }
        //    int id = atoi(PQgetvalue(res, i, 0));
        //string f_vec = PQgetvalue(res, i, 1);
        //double eps_val = atof(PQgetvalue(res, i, 2));
        _out.push_back(_t);
      }
      return _n;
    }
  
  template<class K, class T>
    int postgresMapParser(const char* szQuery, int (*tuple_parser)(PGresult *r, int index, K &k, T &v), std::map<K,T> &_out)
  {
    res = PQexec(conn, szQuery);
    if (!res || (PQresultStatus(res) != PGRES_COMMAND_OK && PQresultStatus(res) != PGRES_TUPLES_OK))
      {
        fprintf(stderr, "PROBLEM %s: %s\n", "query error in postgresTupleParser", PQerrorMessage(conn));
        PQclear(res);
        exit_nicely();
        return -1;
      }
    int _n = PQntuples(res);
    for(int i = 0; i < _n; i ++) {
      K _k;
      T _t;
      if(tuple_parser(res, i, _k, _t) < 0) {     
        fprintf(stderr, "tuple could not be parsed in postgresTupleParser method\n");
        return -1;
      }
      _out[_k] = _t;
    }
    return _n;
  }
  void closeConnection();
};


// Helper functions
void svector_to_dbstring(const SVector& s, std::string& feature_vector_str);
void fvector_to_dbstring(const FVector& v, std::string &feature_values);
void model_to_dbstring(const struct model &m, std::string &model_string, std::string &bias_string);
void checkQueryReturnValue(int retVal, std::string query);

#endif

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