I personally would use a model similar to the following:
The product table would be pretty basic, your main product details:
create table product
(
part_number int, (PK)
name varchar(10),
price int
);
insert into product values
(1, 'product1', 50),
(2, 'product2', 95.99);
Second the attribute table to store the each of the different attributes.
create table attribute
(
attributeid int, (PK)
attribute_name varchar(10),
attribute_value varchar(50)
);
insert into attribute values
(1, 'color', 'red'),
(2, 'color', 'blue'),
(3, 'material', 'chrome'),
(4, 'material', 'plastic'),
(5, 'color', 'yellow'),
(6, 'size', 'x-large');
Finally create the product_attribute table as the JOIN table between each product and its attributes associated with it.
create table product_attribute
(
part_number int, (FK)
attributeid int (FK)
);
insert into product_attribute values
(1, 1),
(1, 3),
(2, 6),
(2, 2),
(2, 6);
Depending on how you want to use the data you are looking at two joins:
select *
from product p
left join product_attribute t
on p.part_number = t.part_number
left join attribute a
on t.attributeid = a.attributeid;
See SQL Fiddle with Demo. This returns data in the format:
PART_NUMBER | NAME | PRICE | ATTRIBUTEID | ATTRIBUTE_NAME | ATTRIBUTE_VALUE
___________________________________________________________________________
1 | product1 | 50 | 1 | color | red
1 | product1 | 50 | 3 | material | chrome
2 | product2 | 96 | 6 | size | x-large
2 | product2 | 96 | 2 | color | blue
2 | product2 | 96 | 6 | size | x-large
But if you want to return the data in a PIVOT format where you have one row with all of the attributes as columns, you can use CASE statements with an aggregate:
SELECT p.part_number,
p.name,
p.price,
MAX(IF(a.ATTRIBUTE_NAME = 'color', a.ATTRIBUTE_VALUE, null)) as color,
MAX(IF(a.ATTRIBUTE_NAME = 'material', a.ATTRIBUTE_VALUE, null)) as material,
MAX(IF(a.ATTRIBUTE_NAME = 'size', a.ATTRIBUTE_VALUE, null)) as size
from product p
left join product_attribute t
on p.part_number = t.part_number
left join attribute a
on t.attributeid = a.attributeid
group by p.part_number, p.name, p.price;
See SQL Fiddle with Demo. Data is returned in the format:
PART_NUMBER | NAME | PRICE | COLOR | MATERIAL | SIZE
_________________________________________________________________
1 | product1 | 50 | red | chrome | null
2 | product2 | 96 | blue | null | x-large
As you case see the data might be in a better format for you, but if you have an unknown number of attributes, it will easily become untenable due to hard-coding attribute names, so in MySQL you can use prepared statements to create dynamic pivots. Your code would be as follows (See SQL Fiddle With Demo):
SET @sql = NULL;
SELECT
GROUP_CONCAT(DISTINCT
CONCAT(
'MAX(IF(a.attribute_name = ''',
attribute_name,
''', a.attribute_value, NULL)) AS ',
attribute_name
)
) INTO @sql
FROM attribute;
SET @sql = CONCAT('SELECT p.part_number
, p.name
, ', @sql, '
from product p
left join product_attribute t
on p.part_number = t.part_number
left join attribute a
on t.attributeid = a.attributeid
GROUP BY p.part_number
, p.name');
PREPARE stmt FROM @sql;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;
This generates the same result as the second version with no need to hard-code anything. While there are many ways to model this I think this database design is the most flexible.
Best Answer
As a horse_with_no_name suggested, I would also go with hstore if you are using PostgreSQL becuase I think its the easiest to morph back to regular table structure if you decide you need that.
There are a couple of features that make hstore pretty nice for your problem:
1) Indexing is pretty fast
2) You can query hstore column with something like
So makes it good for reporting simply by wrapping your different product lines in a view
3) The main downside with hstore is keeping track of properties specific to a particular product type, however you can easily compensate for this with PostgreSQL type system
as demonstrated here: https://stackoverflow.com/questions/16092890/how-can-i-translate-a-postgresql-hstore-column-into-a-row
So you can define say a properties type for shoes called CREATE TYPE shoe_properties(color text, size numeric);
or just use a lookup table of property types and their corresponding data types for editing purposes. Then if you decide later you really want to go with the separate table for properties approach, your job would be simple by just creating a typed table from your type and using popular_record to morph your hstore into a row for insert into table.