I have comments, but let me first explain the work I prototyped so that you have an idea of how I approached the problem.
To add tag support I did 2 things: 1. added a form field for collecting tags on the weblog entry form. 2. created a TagServlet for finding entries with various combinations of tags. I created custom tables for storing my tags ... create table roller_weblogentrytags( id varchar(48) not null, tag varchar(32) not null, weblogentryid varchar(48) not null, primary key(id)); I puposely setup the table to be ultra simple and partially denormalized (i.e. the relationship is really many-to-many, but i didn't setup the tables that way). So the table only maintains the tag value and what entry it corresponds to. At the time I wasn't concerned with maintaining any other metadata regarding a single tag. The TagServlet then allows users to enter a combination of keywords and see what entries come up. The urls for the TagServlet are like this ... /entries/some+combo+of+tags /entries/atagvalue using a "+" indicates an intersection, i.e. only show results that include all the listed tags. Obviously adding the tag collection form fields is trivial, but knowing how to store the data properly so that it's efficient to lookup various tag combinations is tough. I would love to see what the data model for a site like del.icio.us looks like because it would give us some great insights into how they maintain efficiency. Caching could be tough because we will likely get extremely varied queries with different combinations of tags. Then on top of that it would be nice to have the ability to do a lot of the "popular tags" stuff that del.icio.us does. Anways ... I have comments on your email inline below ... On Wed, 2005-09-14 at 12:25, Elias Torres wrote: > Allen, > > I was thinking of using the entryattribute table, what do you think? I > don't think that we want another table for every little feature. At > first I was thinking of something simple, like a "text" field a la > del.icio.us as another + in the settings section of the post that can > be edited by the user anytime. Maybe then using the Tag render plugin > for just rendering the tags and also making sure that Lucene indexes > the tags as well. I don't think we need to worry about the big content > or technorati style dashboards yet, but at least start collecting the > data. hmmm, it depends on how you want to use the entry attribute table. were you going to set a single attribute called "tags" which is a list of all the entry tags? or are you planning to do an attribute per tag? i agree that getting tag data is important, but if you can't use that tag data for something useful then what's the point? if we are going to do tag support then i'd at least like to see some way of finding tagged entries included in the first release. > > I do have a problem with the entryattribute table in general because > it's very limiting. For example, it's really cumbersome if I want to > store both the tag and the date it was inserted on. Even worse, if I > had another piece of metadata about that tagging to insert. It works > for MediaCast right now because you only have attributes about the > entry and not about the actualy entry metadata. I had mentioned to > Dave on IRC that since my day job is on Semantic Web stuff, maybe > making that table a more RDF-friendly table would be really cool for > Roller. this is murky water if you ask me. i think i like the fact that the entryattribute table is a simple hashtable of data attached to a weblog entry, that keeps it simple. if you need to relate complex data to an entry then it's probably best that you create a new table for that data. i am all for reuse of existing architecture as long as it works, but if it is going to inhibit our ability to effectively use the tags then i say forget the entryattribute table and go ahead and do whatever you need to do. i don't really know what you mean by RDF-friendly, so you'd have to elaborate more. -- Allen > > What does everyone think? Who else is using the entryattribute table > besides MediaCast? > > Elias > > On 9/14/05, Allen Gilliland <[EMAIL PROTECTED]> wrote: > > Elias, > > > > I had actually began working on tag support and prototyped it back in > > July, but I didn't get much feedback/support on it so I focused on some > > other things instead. I still have some code that works if that would help. > > > > http://www.rollerweblogger.org/wiki/Wiki.jsp?page=Proposal_WeblogTags > > > > It looks like I had also started a very simple design doc which you are > > welcome to elaborate on. To be honest I don't think adding tag support > > takes much code, but it will require a significant amount of design > > because it will require a lot of dynamic content on concievably large > > sets of data. > > > > I'm definitely looking forward to what you come up with, this would be a > > great addition to Roller. > > > > -- Allen > > > > > > Elias Torres wrote: > > > > >I have updated my patch to now work with DB2. Everything seems to be > > >working beautifully. > > > > > >http://torrez.us/2005/08/23/roller/patches/db2_derby.hibernate3.patch > > > > > >Regards, > > > > > >Elias > > > > > >PS> Now onto tagging. > > > > > >Heads up. I would like to add tagging to Roller, possibly using the > > >metadata table. I'll try to draft something up on the wiki. > > > > > >On 9/13/05, Elias Torres <[EMAIL PROTECTED]> wrote: > > > > > > > > >>Hi Everyone, > > >> > > >>After getting the nice upgrade to Hibernate 3 by Dave, I started > > >>working on testing Derby support first, then DB2. I only found a > > >>couple of issues with Derby so far, everything seems to run fine. > > >> > > >>Here's my patch: > > >>http://torrez.us/2005/08/23/roller/patches/derby_hibernate3.patch > > >> > > >>Basically, > > >> > > >>There was a getInt() that doesn't seem to work on strings for Derby, > > >>so I did this: > > >>- dbversion = rs.getInt(1); > > >>+ dbversion = Integer.parseInt(rs.getString(1)); > > >> > > >>The next one was a query in HibernateRefererManagerImpl.java which is > > >>not performed via Hibernate and there was a "limit" keyword which is > > >>not supported by Derby. I first tried the HSQL version, but Derby > > >>doesn't support TOP either. I added a check on the loop for max > > >>results, somebody please verify that this is ok. Thanks. > > >> > > >>Elias > > >> > > >>PS> Now onto DB2. > > >> > > >> > > >> > >
