Thread: [OT] Inventory systems (private)
Hi All,
is there any whitepaper, document or website that can point me to how to
setup a inventory system?
I'm particulary interested how other people solve the problem of a unknown
number of attributes to a inventory item.
example:
BAL <-- Inventory Item- Color <- Attribute- Diameter <- Attribute- Weight <- Attribute
Car <-- Inventory Item- Speed <- Attribute- Size <- Attribute- Weight <- Attribute- Color
<- Attribute
Computer <-- Inventory Item- Brand <- Attribute- Weight <- Attribute- Windows/Linux
<-Attribute
I can ofcource add any number of columns to a table but for a lot of items
there will be a lot of NULL values and currently I don't know how many
attrubutes one item can have (possible between 10 and 20). This can even
change in feature opon request.
Ries
While I'm not expert what I would do is something like this Items table fields: item_id item_name Attributes table fields: attribute_id attribute_name Item_Attr table fields: item_id attribute_id attribute_value Now an item can be associated with any number of attributes. 03/12/2002 13:17:15, "Ries van Twisk" <ries@jongert.nl> wrote: >Hi All, > >is there any whitepaper, document or website that can point me to how to >setup a inventory system? >I'm particulary interested how other people solve the problem of a unknown >number of attributes to a inventory item. > >example: >BAL <-- Inventory Item > - Color <- Attribute > - Diameter <- Attribute > - Weight <- Attribute > >Car <-- Inventory Item > - Speed <- Attribute > - Size <- Attribute > - Weight <- Attribute > - Color <- Attribute > >Computer <-- Inventory Item > - Brand <- Attribute > - Weight <- Attribute > - Windows/Linux <- Attribute > > >I can ofcource add any number of columns to a table but for a lot of items >there will be a lot of NULL values and currently I don't know how many >attrubutes one item can have (possible between 10 and 20). This can even >change in feature opon request. > >Ries > > >---------------------------(end of broadcast)--------------------------- >TIP 4: Don't 'kill -9' the postmaster >
Troy, Andy,
you both are right and it was my first tought. My only concern is that would
this system be fast enough for large tables (for me large is around 250.000
unique items) and thus my attribute table would be around 2.500.000 and
5.000.000 entrys. A record for one attribute is small I think around 128
byte in size.
One thing is that every attribute must be in it's own domain. For weight for
example I have three different meanings ( 1] Pull weight 2] push weight 3]
weight of the items itself) but using the method troy suggested that would
not be a problem if I create some sort of a domain table.
Anyway so far thangs for the quick responses, I've got something to work on.
best regards,
Ries van Twisk
-----Oorspronkelijk bericht-----
Van: Troy [mailto:tjk@tksoft.com]
Verzonden: dinsdag 3 december 2002 15:47
Aan: Ries van Twisk
CC: pgsql-sql@postgresql.org
Onderwerp: Re: [SQL] [OT] Inventory systems (private)
Ries,
One solution is to create a table such as follows:
CREATE TABLE inventory (id serial, product text,PRIMARY KEY (id)
) ;
CREATE TABLE attributes (prodid int4, textkey text, textvalue text,
int4value int4,FOREIGN KEY (prodid) REFERENCES inventory (id) MATCH FULL ON DELETE CASCADE
ON UPDATE CASCADE
);
INSERT INTO inventory (id, product) VALUES (100, 'Tire');
INSERT INTO attributes (prodid, textkey, textvalue) VALUES (100, 'Type',
'matchbox tire');
INSERT INTO attributes (prodid, textkey, textvalue) VALUES (100, 'Color',
'black');
INSERT INTO attributes (prodid, textkey, int4value, textvalue) VALUES (100,
'Diameter', 12, 'mm');
INSERT INTO attributes (prodid, textkey, int4value, textvalue) VALUES (100,
'Weight', 20, 'g');
CREATE INDEX textkeys ON attributes USING btree (prodid);
CREATE INDEX textkeys2 ON attributes USING btree (prodid,textkey);
To select diameter for product id 100 (Tire):
SELECT prodid FROM attributes WHERE prodid = 100 AND textkey = 'Diameter';
To select several:
SELECT prodid,textkey,textvalue,int4value FROM attributes WHERE prodid = 100
AND textkey IN ('Diameter', 'Weight', 'Color', 'Type');
and so on.
The indexes are just a fast guess. You would need to look at the queries
you generate and decide which indexes are needed.
Cheers,
Troy
Troy Korjuslommi Tksoft Inc.
tjk@tksoft.com
>
> Hi All,
>
> is there any whitepaper, document or website that can point me to how to
> setup a inventory system?
> I'm particulary interested how other people solve the problem of a unknown
> number of attributes to a inventory item.
>
> example:
> BAL <-- Inventory Item
> - Color <- Attribute
> - Diameter <- Attribute
> - Weight <- Attribute
>
> Car <-- Inventory Item
> - Speed <- Attribute
> - Size <- Attribute
> - Weight <- Attribute
> - Color <- Attribute
>
> Computer <-- Inventory Item
> - Brand <- Attribute
> - Weight <- Attribute
> - Windows/Linux <- Attribute
>
>
> I can ofcource add any number of columns to a table but for a lot of items
> there will be a lot of NULL values and currently I don't know how many
> attrubutes one item can have (possible between 10 and 20). This can even
> change in feature opon request.
>
> Ries
>
>
> ---------------------------(end of broadcast)---------------------------
> TIP 4: Don't 'kill -9' the postmaster
>
Ries,
One solution is to create a table such as follows:
CREATE TABLE inventory (id serial, product text, PRIMARY KEY (id)
) ;
CREATE TABLE attributes (prodid int4, textkey text, textvalue text, int4value int4,FOREIGN KEY (prodid) REFERENCES
inventory(id) MATCH FULL ON DELETE CASCADE ON UPDATE CASCADE
);
INSERT INTO inventory (id, product) VALUES (100, 'Tire');
INSERT INTO attributes (prodid, textkey, textvalue) VALUES (100, 'Type', 'matchbox tire');
INSERT INTO attributes (prodid, textkey, textvalue) VALUES (100, 'Color', 'black');
INSERT INTO attributes (prodid, textkey, int4value, textvalue) VALUES (100, 'Diameter', 12, 'mm');
INSERT INTO attributes (prodid, textkey, int4value, textvalue) VALUES (100, 'Weight', 20, 'g');
CREATE INDEX textkeys ON attributes USING btree (prodid);
CREATE INDEX textkeys2 ON attributes USING btree (prodid,textkey);
To select diameter for product id 100 (Tire):
SELECT prodid FROM attributes WHERE prodid = 100 AND textkey = 'Diameter';
To select several:
SELECT prodid,textkey,textvalue,int4value FROM attributes WHERE prodid = 100 AND textkey IN ('Diameter', 'Weight',
'Color','Type');
and so on.
The indexes are just a fast guess. You would need to look at the queries
you generate and decide which indexes are needed.
Cheers,
Troy
Troy Korjuslommi Tksoft Inc.
tjk@tksoft.com
>
> Hi All,
>
> is there any whitepaper, document or website that can point me to how to
> setup a inventory system?
> I'm particulary interested how other people solve the problem of a unknown
> number of attributes to a inventory item.
>
> example:
> BAL <-- Inventory Item
> - Color <- Attribute
> - Diameter <- Attribute
> - Weight <- Attribute
>
> Car <-- Inventory Item
> - Speed <- Attribute
> - Size <- Attribute
> - Weight <- Attribute
> - Color <- Attribute
>
> Computer <-- Inventory Item
> - Brand <- Attribute
> - Weight <- Attribute
> - Windows/Linux <- Attribute
>
>
> I can ofcource add any number of columns to a table but for a lot of items
> there will be a lot of NULL values and currently I don't know how many
> attrubutes one item can have (possible between 10 and 20). This can even
> change in feature opon request.
>
> Ries
>
>
> ---------------------------(end of broadcast)---------------------------
> TIP 4: Don't 'kill -9' the postmaster
>
You might create a seperate attribute tables. table: items id name table: attributes id description table: item_attributes item_id attribute_id SELECTitems.name, attributes.description FROMitems, attributes, item_attributes WHERE items.id=item_attributes.item_idAND item_attributes.item_id = attributes.id; If some items are also attributes of other items (a car has an engine) you might look at tree structures. Of course there are already existing inventory systems that it might be cheaper to use than to grow your own. On Tue, 3 Dec 2002, Ries van Twisk wrote: > Hi All, > > is there any whitepaper, document or website that can point me to how to > setup a inventory system? > I'm particulary interested how other people solve the problem of a unknown > number of attributes to a inventory item. > > example: > BAL <-- Inventory Item > - Color <- Attribute > - Diameter <- Attribute > - Weight <- Attribute > > Car <-- Inventory Item > - Speed <- Attribute > - Size <- Attribute > - Weight <- Attribute > - Color <- Attribute > > Computer <-- Inventory Item > - Brand <- Attribute > - Weight <- Attribute > - Windows/Linux <- Attribute > > > I can ofcource add any number of columns to a table but for a lot of items > there will be a lot of NULL values and currently I don't know how many > attrubutes one item can have (possible between 10 and 20). This can even > change in feature opon request. > > Ries > > > ---------------------------(end of broadcast)--------------------------- > TIP 4: Don't 'kill -9' the postmaster >
Ries,
Sorry I missed a few days here. I was busy elsewhere.
Anyway, the speed issue is fixed with indexes. Once you know
the kind of queries you will be making, create an optimized index for
each one of those queries.
You probably want to have a separate table for storing
the attribute names. I.e. instead of using a text variable
in each record, use a unique id which references an entry
in an attributes table. This won't affect the speed of the
system but it will save some space. Or if nothing else, it will
be more elegant.
Cheers,
Troy
>
> Troy, Andy,
>
> you both are right and it was my first tought. My only concern is that would
> this system be fast enough for large tables (for me large is around 250.000
> unique items) and thus my attribute table would be around 2.500.000 and
> 5.000.000 entrys. A record for one attribute is small I think around 128
> byte in size.
>
> One thing is that every attribute must be in it's own domain. For weight for
> example I have three different meanings ( 1] Pull weight 2] push weight 3]
> weight of the items itself) but using the method troy suggested that would
> not be a problem if I create some sort of a domain table.
>
> Anyway so far thangs for the quick responses, I've got something to work on.
>
> best regards,
> Ries van Twisk
>
>
>
>
> -----Oorspronkelijk bericht-----
> Van: Troy [mailto:tjk@tksoft.com]
> Verzonden: dinsdag 3 december 2002 15:47
> Aan: Ries van Twisk
> CC: pgsql-sql@postgresql.org
> Onderwerp: Re: [SQL] [OT] Inventory systems (private)
>
>
> Ries,
>
> One solution is to create a table such as follows:
>
> CREATE TABLE inventory (id serial, product text,
> PRIMARY KEY (id)
> ) ;
> CREATE TABLE attributes (prodid int4, textkey text, textvalue text,
> int4value int4,
> FOREIGN KEY (prodid) REFERENCES inventory (id) MATCH FULL ON DELETE CASCADE
> ON UPDATE CASCADE
> );
>
> INSERT INTO inventory (id, product) VALUES (100, 'Tire');
>
> INSERT INTO attributes (prodid, textkey, textvalue) VALUES (100, 'Type',
> 'matchbox tire');
> INSERT INTO attributes (prodid, textkey, textvalue) VALUES (100, 'Color',
> 'black');
> INSERT INTO attributes (prodid, textkey, int4value, textvalue) VALUES (100,
> 'Diameter', 12, 'mm');
> INSERT INTO attributes (prodid, textkey, int4value, textvalue) VALUES (100,
> 'Weight', 20, 'g');
> CREATE INDEX textkeys ON attributes USING btree (prodid);
> CREATE INDEX textkeys2 ON attributes USING btree (prodid,textkey);
>
> To select diameter for product id 100 (Tire):
> SELECT prodid FROM attributes WHERE prodid = 100 AND textkey = 'Diameter';
>
> To select several:
> SELECT prodid,textkey,textvalue,int4value FROM attributes WHERE prodid = 100
> AND textkey IN ('Diameter', 'Weight', 'Color', 'Type');
>
>
> and so on.
>
> The indexes are just a fast guess. You would need to look at the queries
> you generate and decide which indexes are needed.
>
>
>
> Cheers,
>
>
> Troy
>
> Troy Korjuslommi Tksoft Inc.
> tjk@tksoft.com
>
>
>
>
> >
> > Hi All,
> >
> > is there any whitepaper, document or website that can point me to how to
> > setup a inventory system?
> > I'm particulary interested how other people solve the problem of a unknown
> > number of attributes to a inventory item.
> >
> > example:
> > BAL <-- Inventory Item
> > - Color <- Attribute
> > - Diameter <- Attribute
> > - Weight <- Attribute
> >
> > Car <-- Inventory Item
> > - Speed <- Attribute
> > - Size <- Attribute
> > - Weight <- Attribute
> > - Color <- Attribute
> >
> > Computer <-- Inventory Item
> > - Brand <- Attribute
> > - Weight <- Attribute
> > - Windows/Linux <- Attribute
> >
> >
> > I can ofcource add any number of columns to a table but for a lot of items
> > there will be a lot of NULL values and currently I don't know how many
> > attrubutes one item can have (possible between 10 and 20). This can even
> > change in feature opon request.
> >
> > Ries
> >
> >
> > ---------------------------(end of broadcast)---------------------------
> > TIP 4: Don't 'kill -9' the postmaster
> >
>
>
> ---------------------------(end of broadcast)---------------------------
> TIP 5: Have you checked our extensive FAQ?
>
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