Chapter 5. Alter data of a column

We alter now the data of the column. Just give the new value as a parameter to the method hk_column::set_asstring().


Example 5-1. Alter data of a column

   1 #include <hk_classes.h>
   2 #include <iostream>
   3 int main()
   4 {
   5    hk_drivermanager* mydrivermanager = new hk_drivermanager();
   6    if (mydrivermanager==NULL) {cout <<"error creating mydrivermanager"<<endl;exit(1);}
   7    hk_connection* myconnection = mydrivermanager->new_connection("mysql");
   8    if (myconnection==NULL) {cout <<"error creating myconnection"<<endl;exit(1);}
   9    myconnection->set_host("localhost");
  10    myconnection->set_user("root");
  11    myconnection->set_password("mypasswd");
  12    myconnection->connect();
  13 
  14    hk_database* mydatabase=myconnection->new_database("exampledb");
  15    if (mydatabase==NULL) {cout <<"error creating mydatabase"<<endl;exit(1);}
  16    hk_datasource* mydatasource= mydatabase->new_table("authors");
  17    if (mydatasource==NULL) {cout <<"error creating mydatasource"<<endl;exit(1);}
  18    mydatasource->enable();
  19 
  20    hk_column* mycolumn = mydatasource->column_by_name("name");
  21    if (mycolumn==NULL) {cout <<"error getting column"<<endl;exit(1);}
  22    mycolumn->set_asstring("my new data");
  23    mydatasource->store_changed_data();
  24    delete mydrivermanager;
  25 }

The method mydatasource->store_changed_data(); will store the changes. The data will also be stored when you move the rowselector to another row (hk_datasource::goto_row()) or when you disable the datasource (hk_datasource::disable()).