Question

I am using JvMemoryData to populate a JvDBUltimGrid. I’m primarily using this JvMemoryData as a data structure, because I am not aware of anything else that meets my needs.

I’m not working with a lot of data, but I do need a way to enumerate the records I am adding to JvMemoryData. Has anyone done this before? Would it be possible to somehow ‘query’ this data using TSQLQuery?

Or, is there a better way to do this? I’m a bit naive when it comes to data structures, so maybe someone can point me in the right direction. What I really need is like a Dictionary/Hash, that allows for 1 key, and many values. Like so:

KEY1: val1;val2;val3;val4;val5;etc... KEY2: val1;val2;val3;val4;val5;etc... 

I considered using THashedStringList in the IniFiles unit, but it still suffers from the same problem in that it allows only 1 key to be associated with a value.

Answer 1

One way would be to create a TStringList, and have each item’s object point to another TList (or TStringList) which would contain all of your values. If the topmost string list is sorted, then retrieval is just a binary search away.

To add items to your topmost list, use something like the following (SList = TStringList):

Id := SList.AddObject( Key1, tStringList.Create ); InnerList := tStringList(SList.Objects[id]); // for each child in list   InnerList.add( value ); 

When its time to dispose the list, make sure you free each of the inner lists also.

for i := 0 to SList.count-1 do   begin     if Assigned(SList.Objects[i]) then       SList.Objects[i].free;     SList.Objects[i] := nil;   end; FreeAndNil(SList);