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Posted to user-java@ibatis.apache.org by Do...@bedag.ch on 2005/08/18 15:08:34 UTC
Select n+1 Problem
Hi
Concerning the developer guide, it is possible to avoid the select n+1
problem
I have something like this:
Java:
Class Category{
String name;
Collection itemList;
public void setItemList(Collection _itemList) {
this.itemList = _itemList;
}
public void setName(String _name){
this.name=name;
}
...
}
Class Item{
String name;
public void setName(String _Name){
this.name=_name;
}
....
}
Database:
Table Category:
Id name
1 Apple
2 Microsoft
Table Item:
Id CategoryFk name
1 1 OS X
2 1 iLife
3 2 whatever
4 2 worse whatever
Question:
I don't see how I can avoid to make for each category a select to the
item table.
(like this):
List list = sqlMap.queryForList("getCategory",null);
for (Iterator iter = list.iterator(); iter.hasNext();) {
Category category=(Category)iter.next();
List itemList = sqlMap.queryForList("getItem",new
Integer(category.getId));
category.setItemList(itemList);
}
I didn't fully understand the Calendar sample in the developer guide.
TIA Dominic