MySQL Create a function table? - mysql

Question

I am trying to design the layout of the table to work best in the following situation.
I have a product that is sold based on age. The age determines if that product exists for this person and the minimum and maximum one can buy.
Right now i have designed the table as follows:
CREATE TABLE `tblProductsVsAge` (
`id` int(255) AUTO_INCREMENT NOT NULL,
`product_id` bigint(255) NOT NULL,
`age_min` int(255) NOT NULL,
`age_max` int(255) NOT NULL,
`quantity_min` decimal(8) NOT NULL,
`quantity_max` decimal(8) NOT NULL,
/* Keys */
PRIMARY KEY (`id`)
) ENGINE = InnoDB;
this is functional and it work, but i feel as if its not the best optimized structure.
any idea?
i forgot to mention a product can have many ranges. for example age min 25 age max 35 and the quantity for this would be 12 and 28, for the same product ID we might have age 36 to 60, quantity from 3 to 8.

Answer 1

Use tinyint unsigned for age_max and age_min since none of the ages in the question pass 255 (highest unsigned tinyint).
Use smallint unsigned for quantity_max and quantity_min if those values > 255 and <= 65535 (highest unsigned smallint).
Use mediumint unsigned for quantity_max and quantity_min if those values > 65535 and <= 16777215 (highest unsigned mediumint).
Use int unsigned for quantity_max and quantity_min if those values > 16777215 and <= 4294967295 (highest unsigned int). (Sometimes, you gotta Think Big !!!)
My recommendation:
CREATE TABLE `tblProductsVsAge` (
`product_id` int NOT NULL,
`age_min` tinyint unsigned NOT NULL,
`age_max` tinyint unsigned NOT NULL,
`quantity_min` smallint unsigned NOT NULL,
`quantity_max` smallint unsigned NOT NULL,
/* Keys */
PRIMARY KEY (`product_id`, `age_min`)
) ENGINE = InnoDB;
Here is something to consider if the table already has data: You could ask mysql to recommend column defintions for this table.
Simply run this query:
SELECT * FROM tblProductsVsAge PROCEDURE ANALYSE();
The directive PROCEDURE ANALYSE() will cause mysql not to display the data but to examine the values from each column and come up with its own recommendation. Sometimes, the recommendation is too granular. For example, if age_min is in the teenage range, it may recommend ENUM('13','14','15','16','17',18','19') instead of tinyint. After PROCEDURE ANALYSE() is done, you still make the final call on the column definitions.

Answer 2

CREATE TABLE `tblProductsVsAge` (
`product_id` int NOT NULL,
`age_min` smallint NOT NULL,
`age_max` smallint NOT NULL,
`quantity_min` smallint NOT NULL,
`quantity_max` smallint NOT NULL,
/* Keys */
PRIMARY KEY (`product_id`, `age_min`)
) ENGINE = InnoDB;
Changes to your structure:
id is probably not needed (unless you really need it), but then if you need product_id to be bigint then id should have the same type - after all this table can get more rows than your products table,
I changed type od product_id to int, I don't think you will have more than 2147483647 products,
age and quantity are smallints, which can have a maximum value of 32767 (use mediumint or int if it's not enough). decimal is intended for when you need exact precision or numbers bigger than bigint,
index on (id, age_min) to make faster searches for given product_id and for searches like product_id = {some_id} AND min_age > {user_age}
(255) in int/bigint definition doesn't make it 255 digits long - it's only a hint for string representation.
MySQL manual on numeric types: http://dev.mysql.com/doc/refman/5.5/en/numeric-types.html