Question

I have a table , say A ; now in A i have attribute ID as string and Time as DateTime.

Now the condition is that different entries to the table can have same ID and they have to be clubbed together and further do some refinement on it.

I am using java, I write the SQL query that

Select * from A group by ID;

Now i get this data in a huge list in java. Now what i do is

Set_ID=NULL;
for(each element in List)
{
  if(Set_ID equals elements `ID` from table)
    Add the element to the same list
  else
    Create new List and add element to the list. Change Set_ID to current `ID`
}

This way i get all the Entries with same Id in different lists and i can process further.
But is this the efficient way to this; comparing strings for each element.

Any change i can make, to make it better. Thanks.

Answer 1

Instead of reading all the data into a list & then processing it into sub lists, I’d process them directly into sub lists as you pull them from the database