Retrieval Problem !

Question

hi -
I have some doubt regarding some retrieving data.
Here is my table data :
id1 id2 name
35 30 java
35 31 c
36 32 cpp
36 33 vc
37 34 abc
35 tool
36 temp
37 mydir
here is the logic :
if id2 equals to id1 , then i can get retrive the results.
if id1 is null , i can retrieve results too
but if id2 is not equal to id1 ( values are not there in id1 , eg, 34 ) , i could not able to retrieve the results.
how can i get the results of 34 .
i guess , u guys understood the problem.
thanks in advance.
- bregoty

Answer 1

Here is code for your referrence.
import java.util.*;
parentId id          name
35           30          java
35           31          c
35           32          cpp
37           33          vc
37           34          abc
null      35          tool
null      36          temp
null      37          mydir
public class Example
     public static void main(String[] args)
          HashMap itemMap = new HashMap();
HashMap parentNullMap = new HashMap();
          Item it = null;
/* parentId , id and name values coming from the
he database and that will be stored.
             Hashmap having counter and Item object .*/
          for (int i=0;i<10;i++)
               String parentId = resultSet.getString(1);
               String id = resultSet.getString(2);
               String name = resultSet.getString(3);
               it = new Item();
               it.setParentId(parentId);
               it.setId(id);
               it.setName(name);
               itemMap.put(String.valueOf(i),it);
// saving id values into the Map if parentId is
is null
               if (parentId == null)
                    parentNullMap.put(parentId,id);// YOUR parentNullMap will only have one value--the key will be "null", the value will be whatever "id" comes last.
// Item it1 = new Item(); // Unnecessary initialization--just declare value:
Item it1;
for (int i=0;i<parentNullMap.size();i++ ) // will be at most 1, as explained above.
String pnm = parentNullMap.get(String.valueOf(i)); // You didn't use String representations of int as keys.
          for (int j=0;j<itemMap.size() ;j++ )
it1 = (Item)itemMap.get(String.valueOf(j))
// if id is equals to parentId
if (pnm.equals(it1.getId()))
// will get the results if it equals
// need to get the results if it is not
if it is not there in parentId column .
// i mean i need to get the record of
the record of 36.
Make parentNullMap a HashSet. Put the id values into it. Use an Iterator to loop through it.