/home/tobi/workspace/solarpowerlog/src/interfaces/PersistanceStorage/IPersistanceStorage.cpp

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/*
 * IPersistanceStorage.cpp
 *
 *  Created on: Jan 18, 2010
 *      Author: tobi
 */

#include "IPersistanceStorage.h"
#include "QueryHelper.h"
#include <assert.h>

#include <iostream>

#include "configuration/CConfigHelper.h"

IPersistanceStorage::IPersistanceStorage(std::string &configname,
          std::string &table) :
     config(configname), table(table)
{

     std::string tmp;
     session_ready = false;

     // get configuration.
     CConfigHelper cfg(configname);
     CConfigHelper cfg_root("application");

     if (!(cfg.GetConfig("dbi_driver", tmp) || cfg_root.GetConfig("dbi_driver",
               tmp))) {
          session.driver(tmp);
     }

     // Check for configuration array.
     CConfigHelper dbi_cfg1(configname + ".dbi_db_cfg");
     CConfigHelper dbi_cfg2("application.dbi_db_cfg");

     CConfigHelper &dbi_cfg = dbi_cfg1;
     if (!dbi_cfg1.GetConfigArray(0, 0, tmp)) {
          dbi_cfg = dbi_cfg2;
     }

     std::string value;
     long numericvalue;
     for (int i = 0;; i++) {
          if (dbi_cfg.GetConfigArray(i, 0, tmp)) {
               if (dbi_cfg.GetConfigArray(i, 1, numericvalue)) {
                    session.param(tmp, numericvalue);
               } else if (dbi_cfg.GetConfigArray(i, 1, value)) {
                    session.param(tmp, value);
                    if (tmp == "dbname")
                         dbname = tmp;
               } else {
                    // FIXME: Not integer nor string....
                    // Do error reporting.
                    continue;
               }

          } else
               break;
     }

}

IPersistanceStorage::~IPersistanceStorage()
{
     session.close();
     // TODO Auto-generated destructor stub
}

void IPersistanceStorage::CheckAndCreateTable(void)
{

     assert(table_spec.size());

     // Check if table exists.
     if (!session_ready) {
          try {
               session.connect();
               session_ready = true;
          } catch (...) {
               // FIXME: Error reporting
               return;
          }
     }

     dbi_conn conn = session.get_dbi_conn();
     dbi_result res = dbi_conn_get_table_list(conn, dbname.c_str(),
               table.c_str());

     unsigned int i = dbi_result_get_numfields(res);
     if (i == 0 || i == DBI_FIELD_ERROR) {
          // Table not there.
          std::string query = "CREATE TABLE " + table + " ( ";
          for (unsigned int j = 0; j < table_spec.size(); j++) {
               if (j)
                    query += ",";
               query += " ? ? ";
          }
          query += ")";
          session.query(query);

          std::map<std::string, dbtypes>::iterator it = table_spec.begin();
          for (it = table_spec.begin(); it != table_spec.end(); it++) {
               session.bind((*it).first);

               switch ((*it).second)
               {
               case db_integer:
               case db_unsignedinteger:
                    session.bind("INTEGER");
                    break;

               case db_longlong:
               case db_unsignedlonglong:
                    session.bind("BIGINT");
                    break;

               case db_decimal:
                    session.bind("FLOAT");
                    break;

               case db_tm:
                    session.bind("TIMESTAMP");
                    break;

               case db_string:
                    session.bind("VARCHAR(255)");
                    break;

               }
          }

          // create table syntax done.
          try {
               session.exec();
          } catch (dbixx::dbixx_error e) {
               // FIXME: Error reporting!
               cerr << "Query Error " << e.what() << endl;
          }
          return;
     }

     // table exists, check if every column is there.
     // - First do a query on the table getting (one) result with every table.
     // - 2nd iterate over the fieldnames, and check against memorize them (i.e in a list)
     // - 3rd find out if any field is missing (iterate over map and check in list if exists)
     // - 4th create ALTER TABLE syntax for missing fields.


     // The map is quicker in search, so we can live with the memory overhead imposed here.
     // as a speed trade-off.
     std::map<std::string, dbtypes> missing_columns = table_spec;

     conn = session.get_dbi_conn();
     res = dbi_conn_queryf(conn, "SELECT * FROM %s LIMIT 1", table.c_str());
     if (!res) {
          // FIXME Error Handling
          cerr << "libdbi: SELECT * FROM " << table << " LIMIT 1 returned NULL";
          return;
     }

     unsigned int num_columns = dbi_result_get_numfields(res);
     if (num_columns == 0 || num_columns == DBI_FIELD_ERROR) {
          // FIXME Error Handling
          cerr << "libdbi: SELECT * FROM " << table
                    << " LIMIT 1 returned no columns or DBU_FIELD_ERROR";
          num_columns = 0;
     }

     // 2 and 3
     for (unsigned int i = 1; i <= num_columns; i++) {
          const char *tmp;
          tmp = dbi_result_get_field_name(res, i);
          if (missing_columns.erase(std::string(tmp))) {
               // FIXME: Here some place of debug code.
               cerr << "TABLE CONTAINS ALREADY " << tmp << endl;
          }
     }

     // 4th
     if (!missing_columns.empty()) {
          std::string query = "ALTER TABLE ? ADD COLUMN ";
          if (missing_columns.size() > 1)
               query += "(";
          std::map<std::string, dbtypes>::iterator it;
          for (unsigned int i = 0; i < missing_columns.size(); i++) {
               if (i)
                    query += ",";
               query += " ? ?";
          }
          session << query;

          for (it = missing_columns.begin(); it != missing_columns.end(); it++) {
               session.bind((*it).first);

               switch ((*it).second)
               {
               case db_integer:
               case db_unsignedinteger:
                    session.bind("INTEGER");
                    break;

               case db_longlong:
               case db_unsignedlonglong:
                    session.bind("BIGINT");
                    break;

               case db_decimal:
                    session.bind("FLOAT");
                    break;

               case db_tm:
                    session.bind("TIMESTAMP");
                    break;

               case db_string:
                    session.bind("VARCHAR(255)");
                    break;

               }
          }

          if (missing_columns.size() > 1)
               query += ")";

          try {
               session.exec();
          } catch (dbixx::dbixx_error e) {
               // FIXME: Error reporting!
               cerr << "Query Error " << e.what() << endl;
          }

     }

}