I thought of another way to do your copy/cut/paste...
Assuming you keep the original audio around and use the levels I showed before.
create table sequence(level int,parent int,start int,end end);
insert into seqeunce values(1,0,0,-1); // note that -1 means "until end of
data".
See where I'm going? You keep a sequence table that is much like your btree.
It's just a collection of clips that when strung together can make your audio
clip. By default you have one sequence per level.
Cut 1000-1999 from level=1
select * from sequence where level=1;
delete from sequence where level=1;
insert into sequence values(1,0,0,999);
insert into sequence values(2,1,2000,-1);
Insert some data:
1st you find where it fits
select * from sequence where level=1;
bytes1=0;
while moredata
bytes2+=end-start;
if (insertpoint >=bytes1 and insertpoint <=bytes2)
update sequence set id=id+1,parent=parent+1 where id>=currentid;
break;
end
Cuts are just splitting one record in 2, or adjusting 2 records and deleting
records in between.
I'll leave that as an exercise for you.
This would
Michael D. Black
Senior Scientist
NG Information Systems
Advanced Analytics Directorate
________________________________
From: sqlite-users-boun...@sqlite.org [sqlite-users-boun...@sqlite.org] on
behalf of Christopher Melen [relativef...@hotmail.co.uk]
Sent: Sunday, July 10, 2011 12:52 PM
To: sqlite-users@sqlite.org
Subject: EXT :[sqlite] Storing/editing hierarchical data sets
Hi,
I am developing an application which analyses audio data, and I have recently
been looking into Sqlite as a possible file format. The result of an analysis
in my application is a hierarchical data set, where each level in the hierarchy
represents a summary of the level below, taking the max of each pair in the
sub-level, in the following way:
251 214
251 54 201 214
251 91 17 54 31 201
214 66
251 18 5 91 11 17 54 16 9 31 201 148 173 214 43 66
Such a structure essentially represents the same data set at different levels
of resolution ('zoom levels', if you like). My first experiments involved a
btree-like structure (actually something closer to an enfilade* or counted
btree**), where the data stored in each node is simply a summary of its child
nodes. Edits to any node at the leaf level propagate up the tree, whilst large
edits simply entail unlinking pointers to subtrees, thus making edits on any
scale generally log-like in nature. This works fine as an in-memory structure,
but since my data sets might potentially grow fairly large (a few hundred MB at
least) I need a disk-based solution. I naively assumed that I might be able to
utilize Sqlite's btree layer in order to implement this more effectively; this
doesn't seem possible, however, given that the btree layer isn't directly
exposed, and in any case it doesn't map onto the user interface in any way that
seems helpful for this task.
I am aware of some of the ways in which hierarchical or tree-like structures
can be represented in a database (adjacency lists, nested sets, materialized
paths, etc.), but none of these seems to offer a good solution. What I'm
experimenting with at present is the idea of entering each node of the
hierarchy into the database as a blob (of say, 1024 bytes), while maintaining a
separate in-memory tree which then maps on to this flat database of nodes (each
node in the tree maintains a pointer to a node in the database).
I would be very interested in
thoughts/observations
on this problem - or even better a solution!
Many thanks in advance,
Christopher
* http://en.wikipedia.org/wiki/Enfilade_(Xanadu)
** http://www.chiark.greenend.org.uk/~sgtatham/algorithms/cbtree.html
_______________________________________________
sqlite-users mailing list
sqlite-users@sqlite.org
http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
_______________________________________________
sqlite-users mailing list
sqlite-users@sqlite.org
http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
