Hello. I'm Andrew Hyatt. I've been working on Emacs,
with Emacs, and to some extent
on Emacs for a while. I've written the WebSockets library
and Emacs calc tutorials. I've enjoyed use of
many of everyone's incredible packages.
So my thesis for this talk, why I'm giving this talk,
is that I'm interested in SQLite.
I think we should be exploring SQLite for applications
in ways I think the community has shied away from.
I'd like to introduce the triples package as a way,
both easy and with interesting functionality,
that will allow us to build extensible databases
in a way that is, I think,
a little bit unusual and perhaps compelling, I hope.
So first of all, why SQLite?
Why is this good? Well, SQLite is now built into Emacs.
So you get a few things out of this when you use it for data.
First of all, it's a database.
It's extremely good for data, of course.
There's a simplicity to data manipulation
using a database, compared to data manipulation,
that is, manipulating data in a text file.
Text files are really not built for data.
So when typically when you need to do this,
like I know Org Mode is--
which I'm a huge, huge Org Mode fan--
it's all about sort of data in text.
It does work, but you certainly would be
hard pressed to make sweeping changes
to your database that is represented in text.
It's just not well suited for this sort of thing.
It would take a long time,
where the speed of SQL is incredibly impressive.
I think certainly Emacs is not known
for being extremely speedy.
I think the overuse of text
is part of this. Of course, text and using text,
using files has awesome advantages as well.
I'm really here to talk about
the other side of the coin, right?
Everyone can judge
those advantages and disadvantages
and make their own trade-offs,
but I want to kind of
make the pitch for SQLite.
So let's talk about the triples package.
The triples package is a package
that is designed to give you a very generic schema.
You don't have to do,
for most of the common operations,
you don't have to write SQL yourself.
A lot of stuff is built in
and is based on a very generic schema.
That is, it's a single table.
That table has, of course, fixed schema.
It basically has three columns.
It actually has four columns.
In this talk, I'm not going to get into
the fourth column and why, but it's useful.
So the three columns are subject, predicate,
and object. This is what it's related to
what we call an RDF format.
These things basically describe a link.
The link is from the subject to the object.
The link type is a predicate.
That sounds overly theoretical,
but the point is that you can describe
a lot of things with this format.
You probably describe everything with it.
It's very simple because the schema is fixed.
It's only this kind of data. That means
for your application, you define a schema
in subject, predicate, object format.
That defines what data you can use,
what types there are, what properties they have,
how you can use the system,
and what is legal to do. And this is stored as data.
I think as Lisp people,
I think we're all very onboard
with the fact that you have a simple way
to express everything, and you don't have these
two systems. In this way,
you don't have to have code as a system.
Do you have to load code to use the triples package
to make sure your schema is obeyed?
No, it's all just built in to this database.
I'll describe this. As I said,
it's a little bit abstract right now,
but it will become a lot clearer
when we go through an example,
which we're going to do now.
As an exercise, let's create Emacs bookmarks,
which basically are three things:
a name, a file, and an annotation.
I may be missing out on functionality.
Of course, everything in Emacs,
everything has lots and lots of functionality,
but let's just start with this simple thing.
First of all, we're going to open up a database.
Pretty simple.
I think there's nothing to explain there.
But here on this line that I'm on right now,
we are saying, okay, there's going to be
a type called bookmark.
It's going to have the following properties.
First, a file, which is unique and a string.
The second is an annotation,
which is again unique and a string.
Then we're going to have another type called named.
First of all, why is it named as part of bookmark?
As I'll get into, it's interesting
when you start sharing this database
with other things, not just bookmarks, but other types.
Bookmarks are very similar to many other things
that you might want to expand into.
Those other things have names,
but they're not bookmarks.
It's nice to separate these concerns out
and just have another type called named,
which just basically has a name.
We can execute this.
It's not interesting to look at these.
that is not all that useful for anything,
It outputs something
but that's okay. What's done is, actually,
it's created a database
and it's populated it with the schema.
We can look at this.
We won't go through all of this
because it's a little bit too much
for a short presentation like this,
but you could see that there's something here
that's like, oh, we have a subject bookmark.
We have a property base/type.
That just means that there's a property
that's defined by the base.
This means this is from the triples package itself.
It's not some other package.
Third is, what is the type of this object?
It's a schema. This thing could be many types.
As I said, if you have a--
we haven't seen an example yet,
but if you have a bookmark,
it's going to have a name type
and a bookmark type.
Everything is multi-typed
and that's kind of a feature
of this kind of storage system.
I'm not going to go through everything,
but you can see it's all there in triples,
the whole schema, everything we just did.
Let's create a bookmark. Again,
we're going to connect to our database
and we're going to basically set
an entire subject.
The subject is, it's basically like an entity.
We're going to define a whole entity
or you could refer to it as an object.
That's a perfectly fine way to look at it, I think.
It's going to have some identifier.
That identifier could be anything.
It doesn't have to be a string.
It could really be anything, but we're going
to give it a string called emacs-init.
It does not matter what this identifier is,
at least for our purposes.
It does matter when you're linking to it,
but I think nothing that I'm about to show you.
This could truly be anything
because it has a separate name.
I'm giving it a name here, which is init.
I'm just specifying the named type here
and I'm specifying the bookmark type here
and its values. We're going to do that.
Now, if we look, we see everything we saw before,
but now we have subject emacs-init.
It has a type and it's named.
We also see the same thing two lines down.
This type is also a bookmark,
but the name is init in the named/name,
which is like the type is name, named,
and the property is name. It's init.
As you can see, this is just
how everything looks.
It's pretty straightforward
and you can retrieve it.
Now, we're looking at the database,
but you don't really have to
look at the database for... In fact,
I think we're done looking
at the triples format,
because I think it's very simple.
You've already got the hang of it, I think.
Let's retrieve that just to make sure, yes,
we can retrieve it.
We're going to retrieve it and say, okay,
what do we get when we load the emacs-init subject?
Well, we get a plist of all of its properties,
which then you can use in your application.
There's many more ways to retrieve
and there's many more ways to save.
In fact, I think the way I did it here
with set subject is probably not
the right way to do it most of the time.
It's usually because it'll erase everything.
It's only really to be used when
you're sure you control all the data,
but you're never sure because there could be
other packages that are also using this database,
they could have their own data.
You don't want to erase
all the other Emacs init subject data.
In this case, we did because
we are confident it was a new entity,
but in most cases, the right thing to do is
just set it by type. Just say,
we're just going to set the bookmark type,
which is... The properties are this,
and then the name type
and the properties are that.
That's a way that you could do things.
There's also many retrieval types.
The retrieval types:
you can retrieve by a number of different ways,
which I'm not going to get into,
but you can read about in either the source
or the readme in the package.
We have backlinks as well.
Let me explain what backlinks are.
There's another feature of the triples.
As I mentioned, these things
can be thought about as links,
but what could be a link in one direction
could also be a link in the other direction,
and we basically get this for free.
Here's an example where we are again
connecting toward bookmark. Here we're going to
add a new type called tagged.
We're going to give everything in tags.
Here we're saying, okay, there's a type called tagged
and it has a property called tags.
This is not unique, so it's a list basically.
It's a list of string.
There also is a type called tag.
This is for things that are tags themselves.
Then it has a type called numbers
and it has what we call a virtual reversed property.
It's virtual because it's not actually stored.
We just compute it by reversing
the subject and the object.
This is on tagged tags. When we query this,
we can just say, okay,
what are all the subjects
that have tagged tags of me, the tag?
In fact, let me demonstrate that for you.
We're going to set the type on emacs-init.
We're going to add the "tagged" type.
This is the alternate way of setting data
that I mentioned.
This won't erase anything else.
We're just adding something here.
We're adding this type "tagged"
to our previous bookmark emacs-init.
We're going to add emacs and config
as the tags. We're going to then
set emacs as a tag and config as a tag.
That just lets us have this virtual property.
You have to do something.
You can't get it out of thin air.
The design decision we've made is:
you at least need to tag it
before you get the free property.
What you should see... Let's try it out.
We got the subject config,
which we've set no data on.
You can tell we're not sending any data.
If I get that subject, the result is that
it says its members are emacs-init.
That's what a virtual reverse property.
As we tag more things, this just
continues to work because it's just doing
a SQL query here.
Besides showing off the backlinks function,
this also shows off the general way
you can have extensible entities.
That is, it's possible that someone writes
a bookmarks package that stores everything
in a database, in the triples database,
but then someone else can come and say,
okay, I'm going to define my own types
that's meant to work with this database,
just like someone could do what I did here,
just to add simple tagging.
It's very easy to do.
This stuff is not that easy to do otherwise.
To do this in Lisp, I would say it's a little awkward.
With databases, again, it's not only possible,
it's relatively trivial,
especially with this kind of database.
The benefit is it's super easy to work with.
With this kind of generic database,
the drawback is it's not all that efficient
as a special purpose table
that is really built for efficiencies.
A lot of times you have to do multiple lookups
and things like that.
Again, it's a trade-off for various things.
As you can see, this is like
one database for everything.
That means that we don't have to all
contribute to one giant database.
All the packages that use triples,
it doesn't have to be one database,
but it's cool if it does.
I don't know what I want to happen
or what I expect to happen,
but I think an interesting property is that
this is a way for lots of data to live together
and build off each other in ways that I think
are hard to do with other forms of table layouts
and things like that.
Let's talk about a use of it,
which is the EKG package.
The EKG package is something I've written
to demonstrate the triples library
and use it for something I think is interesting,
which is personal knowledge management systems
of the same type, of the same genre
that Org Roam is,
but with different design decisions.
I'll show it in action for a little bit.
Let's just look at... it's all tag-based,
same kind of tags we saw before
when we were playing around
with the bookmarks example application,
What I want to show is: I can look at a tag.
but everything here is...
I could see notes with that tag.
Everything you see here is in the database,
no files involved.
All of this is just a thing
that's an entire object, the entire string.
It works. It has tags.
You can see not only this tag,
but all the other tags associated with it
and their notes.
It's kind of an interesting way to do things.
When you capture it, I think it's interesting.
There's a lot of interesting design elements here.
This tags thing is not part of the buffer.
It's not like Org Roam.
You see here in this other tags,
these are things I've imported from Org Roam.
This is why they look like they do.
They have their own titles because
I just wrote them all in Org Roam.
What it looks like, really, for these notes
is that it's just text.
You really don't have to bother with this metadata.
If I want another tag like pancakes,
I can just add it here. Again, these tags
will turn into data, triple data.
The text is just a triple date[??] as well,
but different to triple data.
All these things are like that.
You can open up any of these things, et cetera.
I think the interesting thing here
is to see the code. It's not super interesting
to look at code for too long,
but we don't have that long.
Whenever we connect--
I just want to point out a few things.
Whenever we connect, we have a schema.
We just do this. Every time we connect,
we just make sure it has the right schema.
This way, the user is up to date.
This schema just looks exactly like
stuff I showed you in the triples
when we were looking at bookmarks.
It's not complicated.
I even have stuff here with people
to use this as a person database.
I haven't figured out how I'm going to use this yet,
but you can see just to do this,
it's really trivial and it's pretty easy.
Let's show a few other things,
like getting all the tags.
Here, we could just say,
let's get the subjects of type tag.
We have all the triples,
all the ones that are of type tag,
all the things that have a subject.
All the subjects that have links,
that have this type, this tag in it,
we can return them all.
of all these objects.
Basically, it just gives you a list
Again, you can think of these things as objects.
All the objects of type tag,
we'll just get them all. Super, super simple.
Triples gives you this functionality
out of the box. It's not that complicated.
What I would like to show,
and that shows my thesis for this whole talk,
is this rename tag. Now, think about
how you would rename a tag in Org Roam
or anything where the tag is part of the files.
It's like how you would re-tag everything
in Org Mode. It's complicated and error-prone
and slow. This is anything,
this is instantaneous and super easy.
Look, that's it. There's not that many places
for an error to live here.
One thing I would like to point out
is that we are doing direct,
not everything has to go through
the triples package. Maybe it should,
but the triples package is a fixed format,
which is why it's okay--
whether it's a good idea, I'm not sure,
but it's okay for client packages
to just directly manipulate the tables.
Here, we're just doing it just to
update all the tags
and then remove and set types
so that the correct thing happens.
As you can see, it's super, super simple.
I think this proves my thesis about
the advantages of applications with SQLite.
Thank you for listening.
I hope this puts ideas in your minds
about taking advantage of this functionality.
I hope to see more things
using the triples library
or otherwise that take advantage of this.
Thank you for your time.