Help with database planning

J

Juliano

Hello, everybody.

I'm a linguist with practical skills on computers/programming.

We've been working with an ontology at my department, and now I need
to create a GUI viewer for the flat file we have.
I tried to write an Ontology class which manages the data read and
parsed from the flat file, but it takes a relatively long time.
Besides, we have plans to set up a website for online display of said
ontology. So, I have been being pushed towards changing the basic plan
and build a DB so that data access will be faster and easier for both
the desktop GUI and the web app. Right now, I'm trying to work with
sqlite, since it can be used as a separate file for the GUI and as a
DB for Django (which may be the choice for the web interface).

I have been redaing some books on DBs but I kind of get stuck when it
comes to the normalization and the planning of the tables. The problem
is that we have basically four fields that can be arranged in a tree-
like structure. Eg:

Concept
|----- Slot
| `------ Facet
| `------ Filler
`----- Slot
`------ Facet
`------ Filler
`------ Filler
...

So, for ONE *concept*, we have, usually, MANY *slots*, each *slot* has
ONE *facet*, and each *facet* can have MORE THAN ONE *filler*.
Besides, some *slots* and *fillers* are themselves *concepts*,
creating a sort of recursive reference.

<begin table>
line_no concepts slots facets fillers
------------------------------------------------------------------------------
00000 ABANDON DEFINITION VALUE "to leave or desert something or
someone"
00001 ABANDON IS-A VALUE EXIT
00002 ABANDON LEXE MAP-LEX "leave behind-V1"
00003 ABANDON LEXE MAP-LEX abandon-V1
(...)
97420 ZULU DEFINITION VALUE "a language or dialect spoken in south
africa and others"
97421 ZULU INSTANCE-OF VALUE OTHER-*****-KORDOFANIAN-LANGUAGE
97422 ZULU LANGUAGE-OF INV LESOTHO
97423 ZULU LANGUAGE-OF INV SOUTH-AFRICA
<end table>

I tried to create index tables for concepts, slots, facets and
fillers, which gave me the following table:

<begin table>
line_no concepts slots facets fillers
------------------------------------------------------------------------------
00000 cn_00000 sl_00048 fc_00007 fl_07349
00001 cn_00000 cn_02605 fc_00007 cn_01768
00002 cn_00000 sl_00121 fc_00002 fl_04329
00003 cn_00000 sl_00121 fc_00002 fl_15009
(...)
97420 cn_05429 sl_00048 fc_00007 fl_01340
97421 cn_05429 cn_02493 fc_00007 cn_03526
97422 cn_05429 cn_02750 fc_00001 cn_02816
97423 cn_05429 cn_02750 fc_00001 cn_04580
<end table>

(cn_XXXXX from concept index, sl_XXXXX from slot index,
fc_XXXXX from facet index, fl_XXXXX from filler index.)

As you can see, only concepts and facets are populated by their own
type of data.
Whereas slots and fillers can be populated by their own types or by
concepts.

What would be a good way to create tables for this situation?
In fact, this is the first time I've ever tried to create a DB, so I'm
completely lost.

I'm looking forward to a reply...

Thank you very much,
Juliano
 
H

Himanshu

2009/11/14 Juliano said:
Hello, everybody.

I'm a linguist with practical skills on computers/programming.

We've been working with an ontology at my department, and now I need
to create a GUI viewer for the flat file we have.
I tried to write an Ontology class which manages the data read and
parsed from the flat file, but it takes a relatively long time.
Besides, we have plans to set up a website for online display of said
ontology. So, I have been being pushed towards changing the basic plan
and build a DB so that data access will be faster and easier for both
the desktop GUI and the web app. Right now, I'm trying to work with
sqlite, since it can be used as a separate file for the GUI and as a
DB for Django (which may be the choice for the web interface).

I have been redaing some books on DBs but I kind of get stuck when it
comes to the normalization and the planning of the tables. The problem
is that we have basically four fields that can be arranged in a tree-
like structure. Eg:

Concept
 |----- Slot
 |        `------ Facet
 |                  `------ Filler
 `----- Slot
          `------ Facet
                    `------ Filler
                    `------ Filler
   ...

So, for ONE *concept*, we have, usually, MANY *slots*, each *slot* has
ONE *facet*, and each *facet* can have MORE THAN ONE *filler*.
Besides, some *slots* and *fillers* are themselves *concepts*,
creating a sort of recursive reference.

<begin table>
line_no concepts        slots   facets  fillers
------------------------------------------------------------------------------
00000   ABANDON DEFINITION      VALUE   "to leave or desert something or
someone"
00001   ABANDON IS-A    VALUE   EXIT
00002   ABANDON LEXE    MAP-LEX "leave behind-V1"
00003   ABANDON LEXE    MAP-LEX abandon-V1
(...)
97420   ZULU    DEFINITION      VALUE   "a language or dialect spoken in south
africa and others"
97421   ZULU    INSTANCE-OF     VALUE   OTHER-*****-KORDOFANIAN-LANGUAGE
97422   ZULU    LANGUAGE-OF     INV     LESOTHO
97423   ZULU    LANGUAGE-OF     INV     SOUTH-AFRICA
<end table>

I tried to create index tables for concepts, slots, facets and
fillers, which gave me the following table:

<begin table>
line_no concepts        slots   facets  fillers
------------------------------------------------------------------------------
00000   cn_00000        sl_00048        fc_00007        fl_07349
00001   cn_00000        cn_02605        fc_00007        cn_01768
00002   cn_00000        sl_00121        fc_00002        fl_04329
00003   cn_00000        sl_00121        fc_00002        fl_15009
(...)
97420   cn_05429        sl_00048        fc_00007        fl_01340
97421   cn_05429        cn_02493        fc_00007        cn_03526
97422   cn_05429        cn_02750        fc_00001        cn_02816
97423   cn_05429        cn_02750        fc_00001        cn_04580
<end table>

(cn_XXXXX from concept index, sl_XXXXX from slot index,
fc_XXXXX from facet index, fl_XXXXX from filler index.)

As you can see, only concepts and facets are populated by their own
type of data.
Whereas slots and fillers can be populated by their own types or by
concepts.

What would be a good way to create tables for this situation?
In fact, this is the first time I've ever tried to create a DB, so I'm
completely lost.

I'm looking forward to a reply...

Thank you very much,
Juliano
Click to expand...

If you have an ontology that doesn't run into GB's of data you could
also consider this. Load it into an in memory data structure of your
choice from the text file. Here are the arguments in favour :-

1) The structure doesn't lend itself nicely to tables. So a relational
database may not be the best choice when you start traversing the
data. Imagine writing a query to get the data and show it as a tree.
2) Changes to the ontology are infrequent so you don't use most of the
ACID facilities the database offers.
3) cyc uses its own proprietory data format which is probably not a
_relational_ database
4) With your own data structure you know where to fix if the
performance is bad. The current poor performance could be due to some
other problem which may not go away on its own on switching to db.
5) Keeping the data in a flat file has the advantage of making it easy
to update and version control. Otherwise you need another program for
editing it.

I am no database expert so let's see if someone has a better table
design suggestion.

Thank You,
++imanshu
 
K

Ken Seehart

Good idea to use Django. I've just started using it and I really like
it. However, I should give you a heads-up: You will probably want to
use a Django migration tool (I'm using South) because the alternative is
basically to rebuild your database each time your model changes.
Unfortunately, South can sometimes get confused when using anything less
sophisticated than PostgreSQL (I switched from MySQL to PostgreSQL for
this reason). I don't know if South or the other various Django
migration tools work with MySQL.

Applying the DRY (don't repeat yourself), you might even consider
running the same code as a local web server instead of implementing a
separate desktop version. But it is just a suggestion; there are
various reasons why you might not want to do that.

On to the DB design question...

One approach would be to make a Generic class that can represent a
concept, slot, or filler, which would have a type field to identify
which of these to use.

class Concept(models.Model):
...

class Slot(models.Model):
...

class Filler(models.Model):
...

class Facet(models.Model):
...

class Generic(models.Model):
TYPE_CHOICES = (
(u'c', u'concept'),
(u's', u'slot'),
(u'f', u'filler'),
}

# Only one of the following is used. The other two are blank.
concept = models.ForeignKey(Concept)
slot = models.ForeignKey(Slot)
filler = models.ForeignKey(Filler)

class ConceptDef(models.Model):
concept = models.ForeignKey(Concept)
slot = models.ForeignKey(Generic)
facet = models.ForeignKey(Facet)
filler = models.ForeignKey(Generic)
 
K

Ken Seehart

Oops, forgot the blank arg. Anyway, this is of course untested code...

# Only one of the following is used. The other two are blank.
concept = models.ForeignKey(Concept, blank=True)
slot = models.ForeignKey(Slot, blank=True)
filler = models.ForeignKey(Filler, blank=True)
 
D

Dennis Lee Bieber

Concept
|----- Slot
| `------ Facet
| `------ Filler
`----- Slot
`------ Facet
`------ Filler
`------ Filler
...

So, for ONE *concept*, we have, usually, MANY *slots*, each *slot* has
ONE *facet*, and each *facet* can have MORE THAN ONE *filler*.
Besides, some *slots* and *fillers* are themselves *concepts*,
creating a sort of recursive reference.
Click to expand...
First thing that initially strikes my mind is that
"each *slot* has ONE *facet*" implies they are not a hierarchy, but on
the same level. And your example seems to follow that -- you show "LEXE"
always linked to "MAP-LEX" and "LANGUAGE-OF" always linked to "INV".

At my level of understanding, that almost makes "facet" a redundant
piece of information; it is only meaningful if it serves to control how
the "filler" is to be processed -- that is, both "IS-A" "EXIT" and
"DEFINITION" "to leave..." are processed the same way, as some generic
"VALUE" entity
<begin table>
line_no concepts slots facets fillers
------------------------------------------------------------------------------
00000 ABANDON DEFINITION VALUE "to leave or desert something or
someone"
00001 ABANDON IS-A VALUE EXIT
00002 ABANDON LEXE MAP-LEX "leave behind-V1"
00003 ABANDON LEXE MAP-LEX abandon-V1
(...)
97420 ZULU DEFINITION VALUE "a language or dialect spoken in south
africa and others"
97421 ZULU INSTANCE-OF VALUE OTHER-*****-KORDOFANIAN-LANGUAGE
97422 ZULU LANGUAGE-OF INV LESOTHO
97423 ZULU LANGUAGE-OF INV SOUTH-AFRICA
<end table>

I tried to create index tables for concepts, slots, facets and
fillers, which gave me the following table:

<begin table>
line_no concepts slots facets fillers
------------------------------------------------------------------------------
00000 cn_00000 sl_00048 fc_00007 fl_07349
00001 cn_00000 cn_02605 fc_00007 cn_01768
00002 cn_00000 sl_00121 fc_00002 fl_04329
00003 cn_00000 sl_00121 fc_00002 fl_15009
(...)
97420 cn_05429 sl_00048 fc_00007 fl_01340
97421 cn_05429 cn_02493 fc_00007 cn_03526
97422 cn_05429 cn_02750 fc_00001 cn_02816
97423 cn_05429 cn_02750 fc_00001 cn_04580
<end table>

(cn_XXXXX from concept index, sl_XXXXX from slot index,
fc_XXXXX from facet index, fl_XXXXX from filler index.)

As you can see, only concepts and facets are populated by their own
type of data.
Whereas slots and fillers can be populated by their own types or by
concepts.
Click to expand...

That is going to be the tricky one... First off -- is "line_no"
significant?

{simplified syntax here:
tablename(column, column...)
where _stuff_ defines a primary [unique, autoincrement] key
and t.c indicates a foreign key linkage}

Concept(_ID_, Term)
a primary key
the concept term/keyword itself

Slot(_ID_, Concept.ID as related, slotType, Concept.ID as slotconcept,
Term, Facet.ID as facet)
a primary key
link to the concept entry this slot is part of
an indicator that this slot is distinct type or references another
concept
link to the referenced concept -- if slotType is "concept", else
Null
the concept term/keyword -- if slotType is "distinct", else Null
link to the facet

Facet(_ID_, Term)
primary key
term or keyword for the facet

Filler(_ID_, Slot.ID, fillerType, Concept.ID as fillerconcept, Text)
primary key
link to the slot filler is part of
indicator if the filler is distinct (likely text string) or
references another concept
link to the referenced concept or Null, based on fillerType
distinct data (text string) or Null, based upon fillerType


Concept:
0 ABANDON
1768 EXIT
2493 INSTANCE-OF
2605 IS-A
2750 LANGUAGE-OF
2816 LESOTHO
3526 OTHER-*****-KORDOFANIAN-LANGUAGE
4580 SOUTH-AFRICA
....
n ZULU

Facet:
0 VALUE
1 MAP-LEX
2 INV

Slot:
0 0 slot Null DEFINITION 0
1 0 concept 2605 Null 0
2 0 slot Null LEXE 1
....
m n slot Null DEFINITION 0
m+1 n concept 2493 Null 0
m+2 n concept 2750 Null 2

Filler:
0 0 text Null "to leave..."
1 1 concept 1768 Null
2 2 text Null "leave behind..."
3 2 text Null "abandon..."
4 m text Null "a language..."
5 m+1 concept 3526 Null
6 m+2 concept 2816 Null
7 m+2 concept 4580 Null


The alternative is to split Filler and Slot into two tables each:

conceptSlot(_ID_, Concept.ID as related, Concept.ID as slotconcept,
Facet.ID as facet)
conceptSlot:
0 0 2605 0
....
m+1 n 2493 0
m+2 n 2750 2

distinctSlot(_ID_, Concept.ID as related, Term, Facet.ID as facet)
distinctSlot:
Slot:
0 0 DEFINITION 0
1 0 LEXE 1
....
m n DEFINITION 0

conceptFiller(_ID_, conceptSlot.ID as related, Concept.ID as
fillerconcept)
conceptFiller:
1 1 1768
2 m+1 3526
3 m+2 2816
4 m+2 4580

textFiller(_ID_, distinctSlot.ID related, Text)
textFiller:
0 0 "to leave..."
1 1 "leave behind..."
2 1 "abandon..."
3 m "a language..."


Assuming all terms etc are text strings, and hence compatible in
data type, recovering (less line numbers) the data content looks
something like...

select Concept.Term, distinctSlot.Term, Facet.Term, textFiller.Text
from Concept
inner join distinctSlot on Concept.ID = distinctSlot.related
inner join Facet on distinctSlot.facet = Facet.ID
inner join textFiller on textFiller.related = distinctSlot.ID
UNION
select Concept.Term, distinctSlot.Term, Facet.Term, c.Term
from Concept
inner join distinctSlot on Concept.ID = distinctSlot.related
inner join Facet on distinctSlot.facet = Facet.ID
inner join conceptFiller on conceptFiller.related = distinctSlot.ID
inner join Concept as c on c.ID = conceptFiller.fillerconcept
UNION
select Concept.Term, c2.Term, Facet.Term, textFiller.Text
from Concept
inner join conceptSlot on Concept.ID = conceptSlot.related
inner join Facet on conceptSlot.facet = Facet.ID
inner join textFiller on textFiller.related = conceptSlot.ID
inner join Concept as c2 on conceptSlot.slotconcept = c2.ID
UNION
select Concept.Term, c3.Term, Facet.Term, c4.Term
from Concept
inner join conceptSlot on Concept.ID = conceptSlot.related
inner join Facet on conceptSlot.facet = Facet.ID
inner join conceptFiller on conceptFiller.related = conceptSlot.ID
inner join Concept as c4 on c4.ID = conceptFiller.fillerconcept
inner join Concept as c3 on conceptSlot.slotconcept = c3.ID
 

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