I have a doubt regarding a database design, suppose a finance/stock software
in the software, the user will be able to create orders,
those orders may contain company products or third-party products
typical product table:
PRIMARY KEY INT productId
KEY INT productcatId
KEY INT supplierId
VARCHAR(20) name
TEXT description
...
but i also need some more details in the company products like:
INT instock
DATETIME laststockupdate
...
The question is, how should i store the data?
I'm thinking in 2 options:
1 -
Have both company and third-party, products in a single table,
some columns will not be used by third-party products
identify the company products are identified by a supplier id
2 -
Have the company products and third-party in separated tables
3 - [new, thanks RibaldEddie]
Have a single product table,
company products have additional info in a separated table
Thanks in advance!
You didn't mention anything about needing to store separate bits of Vendor information, just that a type of product has extra information. So, you could have one products table and an InHouseProductDetails table that has a productId foreign key back to the products table that stores the company specific information. Then when you run your queries you can join the products table to the details table.
The benefit is that you don't have to have NULLable columns in the products table, so your data is safer from corruption and you don't have to store the products themselves in two separate tables.
Oooo go with 3! 3 is the best!
To be honest, I think the choice of #1 or #2 are completely dependent upon some other factors (I can only thing of 2 at the moment):
How much data is expected (affecting speed of queries)
Is scalability going to be a concern anywhere in the near future (I'd guess within 5 years)
If you did go with a single table for all inventory, then later decided to split them, you can. You suggested a supplier identifier of some sort. List suppliers in a table (your company included) with keys to your inventory. Then it really won't matter.
As far as UNION goes, it's been a while since I've written raw Sql - so I'm not sure if UNION is the correct syntax. However, I do know that you can pull data from multiple tables. Actually just found this: Retrieving Data from Multiple Tables with Sql Joins
I agree with RibaldEddie. Just one thing to add: put a unique constraint on that foreign key in your InHouseProductDetails table. That'll enforce that it's a one-to-one relationship between the two tables, so you don't accidently end up with two InHouseProductDetails records for one product (maybe from some dataload gone awry or something)
Constraints are like defensive driving; they help prevent the unexpected...
I would advice on using point #1. What happens when another supplier comes along? It's also more easy to extend on one product table/produst class.
Take into account the testing of your application also. Having all data in one table raises the possible requirement of testing both the 3rd Party & Company elements of your app for any change to either.
If you're happy that your Unit test would cover this off its not so much of a worry... if you're relying on a human tester then it becomes more of an issue when sizing the impact of changes.
Personally I'd go for the one products table with common details and separate tables for the 3rd party & Company specifics.
one table for products with a foreign key to the Vendor table; include your own company in the Vendor table
the Stock table can then be used to store information about stock levels for any product, not just yours
Note that you need the Stock table anyway, this just make the DB model more company-agnostic - so if you ever need to store stock level information about third-party products, there's no DB change required
Related
I am making a site that has many services to buy, my problem is to find the best way to make an ERD for this structure!
as I show an image I have a routine system for making a contract for a user, in another word I have a simple table to insert a contract and its related information for user and member.
I store all relation of Contract tables in Junction table. but my problem is that I have many services that have a different price that calculates with its own circumstance( FirstServicePrice, SecoundServicePrice **, **ThirthServicePrice and ...).
I decide to use a junction in name of JunctionForFindPrice for keeping each service primary for a contract. 4 example if someone buys the first service I keep just FirstServicePrice ID in JunctionForFindPrice table in FirstServicePriceId field and leave another field null, and then store Id of JunctionForFindPrice in Junction Table (Gray table in Figure).
is it the best Way for this Implementation? is it the correct way?
There are as many pricing schemas as there are applications because everyone does it a little differently, so don't worry: we've all been confused by how to do this the "right" way. One common method is to create a table like [Orders] with fields like [ClientID], [DateOrdered], and [OrderedBy], and another table,[OrderLineItems], that contains each [ServiceID] they add to the order and the price for that service stored as a number ($23.99). Instead of a price junction table, you would have a function or stored procedure that determines the client's price for that service as it's added to the OrderLineItems table.
In my primary application we have a table of "standard prices" for each service with start/stop dates: that allows us to set up price increases in the future. Then we have a table of possible discounts that allow three types of discount, set the new price, discount by x%, or discount by x$. "Discounts" can be negative where we want to charge clients more. This makes for a very flexible pricing structure but the code to figure it all out is very complicated and brittle.
I found a schema in Google Images (see below) that can illustrate a problem I having in my data warehouse design:
My design is different, but this is the simplest figure I could find to convey my question, which is given the figure, I'm wondering how could the schema accommodate the following scenario: if a product had a unique number assigned to it by the SalesOrg (salesOrg_product_number)...For example, a salesOrg sells food items and assigns all food items of the same kind the same unique salesOrg_product_number. A different salesOrg would have a different salesOrg_product_number for that type of product.
I'm inclined to place the salesOrg_product_number attribute in the Product dimension table, but part of me thinks it should be in the salesOrg dimension table instead. I'm wondering which one of these is correct way in a data warehouse (not relational db) design to maintain the star schema?
In a perfect world the Primary Keys of a dimension table should be just surrogate key, without any meaning for the business. Table IDs should be invisible for the final users, but business code should be of course available.
A possible solution would be to have a product table with a structure like:
Product_id
Product_desc
Product_SO1_number
Product_SO2_number
...
Of course this will require to show the correct field to the correct Sales Organization. Depending on your reporting tool this can be more or less difficult. For example if you write your query manually you need just to put the right column in your select.
Another possibility would be to have a product/sales_org table, a table which combine the Product and the Sales_Org one:
Product_Sales_Org_id
Product_id
Sales_Org_id
Product_SO_number
...
This table will be child of the two dimension table and on the fact table you will have Product_Sales_Org_id column. Depending on Product and Sales Organization the Product_SO_number will return the correct number per SO.
If you want to have this in a star schema structure you can put Product/Sales_Org/Product_Sales_Org together in only one table like:
Product_Sales_Org_id
Product_id
Sales_Org_id
Product_desc
Sales_Org_desc
Product_SO_number
...
Sincerely I would go for the second solution, keep the Product and the Sales_Org tables separated, because they are two different business entities and implement the relationship table in the middle.
I hope this helps.
I am thinking about problem in our database.
I have one table for our products. It has few columns that it's for all products common. But products belongs to a manufacture. And each manufacture need some columns for the specification of product. So I am thinking about distributions for our table..
I think that have it all in one table is waste for memory. Because for example I have 20k products for Apple and 30k for Asus, 40k for MSI.. so if I have it all in one table for columns for apple will be NULL for 70k records..
Another idea was that I have few tables for each manufacture and in products has some key that pointing to specific table with columns for Apple.. for example key can be apple1, apple2 and so on. But with this idea it was quite difficult to show all products with theirs specific columns.
So I want to ask if someone thinking about this problem in database.
I am using SQL Server 2012 for our database.
Thanks for any help to this problem.
You can use such structure...
It's just example...
If You want to compare specifications, table with product data will be more complex...
Databases are built to handle information as a collection of related sets ... and to use selection criteria to get you what you want to work with. You should design depending on how your information elements work .. something like:
Manufacturer table (with information that may be peculiar to a
manufacturer (e.g. address, telephone, etc.)
Product table , with a foreign key reference to Manufacturer
You can then select information for, say, Apple with something like
select xxx
from Product p, Manufacturer m
where p.manufacturerID = m.manufacturerID and m.name = "Apple"
We currently have a SQL database with a table that holds online sales for our company, which sells products using other websites (say, Amazon). The table schema has been set up to hold specific sale data/attributes provided by the website our items are currently sold on (say, Site A).
We are expanding sales to other websites that provide different attributes than Site A uses when an item is sold (e.g. Site A might provide a unique sales id number, and site B might not provide a unique sales id number, but also provide some other info that Site A doesn't provide that we still need to capture).
The question is do I add a separate table for sales on each 'site' that we sell on, as the schema will be different, or try to combine all sales into one table, no matter the platform, leaving some columns null if it doesn't pertain to the particular platform? Or maybe a hybrid approach, separating only the attributes that aren't common among the two sites into separate tables, while a "master" sales table holds attributes that are shared (sale_price, sale_date, etc)?
There are also other tables in play that hold internal information (product Ids, costs, etc), that are linked to the sales table via a unique identifier. Whichever route I choose, I'd need come up with a unique identifier I could use across all tables (auto incremented sale_id, e.g.), and store that in a table for reference/joins.
Any suggestions are welcomed!
A sale is a sale >> same data belongs to the same table. I would definitely not recommend splitting your sales to several tables as this creates lots of difficulty for all that might follow: sales statistics and so on. Try to keep all sales in one table.
If it's a very small project, it might be the best shot to integrate the different fields into one table. Otherwise you might try to create profiles for every sale platform: In this case, use an Entity-Attribute-Value model.
Do not add a table for each site. It sounds like you have a many to many relationship between sites and attributes, so set up your database that way. Also, for any unique identifier you need, create it yourself.
I have a problem, I am designing a database which will store different products and each product may have different details.
As an example it will need to store books with multiple authors and store software with different types of descriptions.
This is my current design:
Product_table
|ID|TYPE|COMPANY|
|1|1|1|
attr_table
|ID|NAME|
|1|ISBN10|
|2|ISBN13|
|3|Title|
|4|Author|
details_table
|ID|attr_id|value
|1|3|Book of adventures|
Connector_table
|id|pro_id|detail_id|
|1|1|1|
So the product table would only store the main product id, the company it belongs to and the type of product it is.
Then I would have the attribute table which lists each attribute a product could have, this will make it easier to add new types of products.
The details table will the hold all the values such as different authors, titles isbn10s etc.
And then the connector table would connect the product table and the details table.
My main worry is that the details table will get very large and will be storing lots of different data types.
What i would like would be to split up all of the different types into tables such as ISBN table and author tables.
If this is the case how could i link these tables up to the attr_table
Any help would be greatly appreciated.
Don't bother. You do not say what database you are using, but any reasonable database will be able to handle the details table. Databases are designed to handle big tables efficiently.
If it is really big, you might want to consider partitioning the table by some sort of theme.
Otherwise, just be sure that you have an index on the id in the table and probably on the attr_id as well. The structure should work fine.