That's my class diagram at the moment:
I believe I can control the level of stock at each venue by the difference between the quantity of purchased ingredient and the quantity of beverage sold (as each beverage is composed by ingredient).
However, I have a requirement that should allow users to transfer ingredients between venues, and I am wondering what is the best approach for that...
A new purchase order would add the product to one venue's inventory, but how can I remove it from the other one?
Just in case someone get to this question, here goes my solution:
I decided to create a table transfer_stocks to register all the transfers between venues. This table is also used to solve any discrepancy when stock is counted (when recipient_id is nil, it means wastage or stock missing in the venue -sender_id).
The products in stock is calculated by de difference between purchases, sales and stock transferred.
My class diagram:
Related
I have been given the following scenario :
HyperAV is a retailer of home cinema equipment. They sell a variety of products including televisions, speakers, amplifiers, Blu-ray/DVD players and cables. The company has its head office in Stockport and 5 retail branches around the UK (in London, York, Cardiff, Manchester and Newcastle) and a large warehouse in Birmingham.
Due to the specialised nature of the products most sales are made in the shops which also have demonstration facilities allowing staff to show off the products to customers before they buy. However, the shops can also take orders over the telephone. The company deals with a number of suppliers who deliver items to both the shops and the warehouse. Limited space is available in the shops, so large numbers of items are stored at the warehouse and sent to the shops when their stock runs low.
The company’s buyer and stock controller are based in Stockport and work together to ensure that each branch has an adequate stock level of fast-selling items. If a shop takes an order for a product that it does not hold in stock, payment is taken and the item is sent to the shop from the warehouse. If the warehouse does not have a product in stock, it is ordered from the supplier by the buyer.
From this scenario I have been asked to draw a use case diagram.
I have received feedback but only to an extent where I have been told it is slightly incorrect. I would like to know if anyone can see what is wrong with it or how i can improve it in anyway?
I will not go and analyze what is right/wrong with your business case, but here are a few remarks:
Do not use Generalization with UCs. Each UC shall be a unique added value the system under consideration (SUC) delivers to the actor. If you have Generalization this means your UC is not unique. E.g. Deliver product: these are two absolutely separate UCs. They use a delivery service. But that's a UC for another SUC (namely the delivery service).
Avoid the use of <<include>>/<<extend>> as they indicate the use of functional analysis. UCs are about synthesis which is the opposite of that.
Use verb-substantive to name your UC. Order for example is not a UC.
Think about the "use" in UC. What is the added value it returns to its actor? If that is not of a real use, it's not UC. Process payment is an administrative task, not a UC. So what is the use behind this?
Having a few issues with my database design. I have designed my system like the following image
As you can see it is a pretty basic system to a point. A user can create a supplier by adding supplier details. A user can then add a product and link it to a supplier. Thats the pretty straight forward bit (I hope!). Now I will attach my database design which should hopefully cover what I have mentioned.
So a supplier can have one contact (person within the suppliers company the user of my system will contact) and a supplier can have one to many products.
He is the part I can't figure out. Twice a week, the user of my system will receive stock from all their suppliers. When they receive this stock, they should go into the update stock screen within the application and input the amount of stock they have received for a certain product. I have added a products_stock table which should hopefully put me on my way to cover this aspect (I think it is missing a lot though).
The last screen however is a display of predicted stock. Lets say for instance on the day my products are delivered, I receive 10 units for Product One. I will then manually count the number of units I have left from the last order for Product One (say 2) and update the stock count for Product One to 12.
This means, that really, I only needed 8 units between the two deliveries for product one. The predicted stock screen is supposed to show the predicted stock levels I should place an order for, for a particular product, over a specified time period. So if 8 units was the average stock sold for product one per week, if I wanted to see how many units I should order for product one for a month, it should display about 32 units.
This is not supposed to be a complex system, it should have this manual aspect to it. I have designed the database up until a point, I was hoping I could get some suggestions regarding the products_stock table and how I can handle stock predictions for a specific period of time (if I maybe need additional tables).
Any advice appreciated.
Thanks
Inventory is more like a view and not a table. Inventory is really a series of movements of goods between locations, as well as periodic counts / adjustments.
Inventory is complex. You should play with some inventory software and read some data modeling books.
Use the concepts of Locations (real and virtual) and Movements (a movement should be its own entity).
Item smashes? Move it from its inventory location to the "damaged" location
Item went missing? Move it from inventory to the "ether" location
Found a random Item? Move it from "ether" to inventory
Sold an Item? Move it from inventory to "sold"
Bought an Item? Move it from purchased to inventory
Some other things to keep in mind:
You could sell something, and it's returned, and you put it back in
inventory
You could buy something, but it ain't right, so you send it
back to the seller
You could sell something that you don't own (on
consignment, or not in inventory yet)
You might have something in
inventory that is not currently for sale.
I won't get into the accounting aspects of inventory :)
One possible approach:
Have a separate "stock item" record for each unit received. When it is sold, record the date of sale in this record.
Then if you want to know how many items were sold in a given time range, just count the records with sold dates in that range, like select count(*) from stock_item where product_id=#product and sold_date between #from and #thru. If you need to keep track of items lost to spoilage, theft, whatever, then you might have a status flag of some kind that says whether it's in stock, sold, destroyed, whatever, and also the date of that status.
If the number of units that pass through is large and there's no other reason to keep individual stock records, you could just have "daily sales" records instead, with a date and number sold that day. Same idea.
I am building a new business application for my personal business which has close to ~100 transactions of sale and purchase per day. I am thinking of having Separate tables to record the sale and purchase with another linked table for Items that were sold and a seperate linked table with items that were purchased.
Example:
**SaleTable**
InvoiceNo
TotalAmt
**SaleTableDetail**
LinkedInvNo
ProductID
Quantity
Amount
etc.,
would this design be better or would it be more efficient to have one transactiontable with a column stating sale or purchase?
-From an App/Database/Query/Reporting Perspective
An invoice is not the same as a sales order. An invoice is a request for payment. A sales order is an agreement to sell products to a party at a price on a date.
A sales order is almost exactly the same as a purchase order, except you are the customer, and a sales order line item can reference a purchase order line item. You can put them in separate tables, but you should probably use Table Inheritance (CTI, extending from an abstract Order). Putting them in the same table with a "type" column is called Single Table Inheritance and is nice and simple.
Don't store totals in your operational db. You can put them in your analytic db though (warehouse).
You are starting small, thats a quick way to do. But, I am sure, very shortly you will run into differences between sale and purchase transactions, some fields will describe only a sale and some fields that will be applicable only for purchases.
In due course, you may want to keep track of modifications or a modification audit. Then you start having multiple rows for the same transaction with fields indicating obsoletion or you have to move history records to another table.
Also, consider the code-style-overhead in all your queries, you got to mention the Transaction Type as sale or purchase for simple queries.
It would be better to design your database with a model that maps business reality closest. At the highest level, everything may abstract to a "transaction", with date, amount and some kind of tag to indicate amount is paid or received against what context. That shouldn't mean we can have a table with Tag, Date, Amount, PayOrReceive to handle all the diverse transactions.
Let's consider I have the following not normalized table
1) warehouse
id
item_id
residual
purchase cost
sale cost
Currency
I tried to normalize this and I obtained this tables:
1) warehouse table
id
product_id
residual
cost_id
2) costs table
id
purchase cost
sale cost
Currency
Does that comply with database normal forms?
Thanks much in advance!!!
This should be a comment, but it's too verbose.
There's not enough information to provide an answer - we have to infer structure from context - and the context is confusing. Your initial record looks like a description of a product to be bought and sold - but you've named it as warehouse - which is a place for storing products. I've no idea what you mean by residual. Do you have multiple purchase costs for a specific product? If so how are they differentiated. Similar for sale cost. If ther are multiple costs involved why is the selling price tied to the purchase cost?
I don't know what "residual" means in this context. But just ignoring that ...
I doubt that there's anything to be gained by breaking cost out into a separate table. Let's say we have two products, "toaster model 14" and "men's shirt style X7". Both have a cost of $12. So you create a cost record for $12, and point both records to this. Then you realize that you made a mistake and the toaster really cost $13. So you update the cost record. But that will then update the cost for the shirt also, which is almost surely wrong. Having a separate cost table would mean that you would always create a new cost record every time you created a stock record. Nothing is gained.
The fields you have listed look to me like they all belong in one table. You'd also need an item table that would have data like the description, maybe manufacturer, product specs, etc.
Your warehouse table appears to really be a stocked item table, as it lists items and not warehouses, but whatever. I suspect it also needs some sort of serial number, or how will you link a given physical item in the warehouse to the corresponding record?
If by "sale cost" you mean the price that you will charge to the customer when you sell it, I doubt this belongs in the warehouse table. When a customer buys a product, do you tell him, "I can sell you the one that's in bin 40 in the warehouse for $20 or the one that's in bin 42 for $22. Which do you want?" Probably not. I suspect you charge the same price regardless of which particular unit the customer gets. The fact that the price you have to pay to your supplier went up between when you bought the first one and when you bought the second one normally does not mean that you will charge your customer a different price. You may raise the price, but you will have one price regardless of which unit is sold. Therefore, the selling price goes in the item table, not the warehouse table. If "sale cost" is something else, maybe this whole paragraph is irrelevant.
I'm trying to make the database system point of sale, however I am confused between the entity and product inventory entity. What are the differences between product and inventory?
I know that the inventory should control the amount of product available .... but i have all that in products.
product code
name
description
cost
unit price
Subcategory code
brand code
amount available
Minimum quantity for rehearing
state
tax code
weight
amount wholesales
wholesales price
perishable
due date
creation date
upgrade date
what i should have in inventory? I have researched and according to what I read I need to have the product, the description, the quantity, purchase price, sale price, profit or gain and date of the transactions. But almost everything is in the Products table, what should I do?
A Product is an abstract Good or Service. A Good is the specification of an Asset.
Example "2014 Mazda 3" is a good. A "2014 Mazda 3 with VIN 12345" is an Asset.
A Catalog is the list of products that you want to sell. They don't need to exist yet, or you could be selling them for someone else.
Items Held For Sale are assets that you keep around to sell. These could be consigned (owned by someone else).
Inventory is an accounting concept. It is the dollar value of the items held for sale that you own, plus inbound and outbound goods that you're responsible for, plus any costs associated with holding that inventory.
You can track the value of inventory in a variety of ways such as FIFO and LIFO
I think you can store the inventory in the products table. There will certainly be transaction tables for purchases for the products and sales and even adjusting records (when items get count and the number differs from what's stored in the database), but you can easily work with the stock stored in the production table itself, thus not having to scan the whole database and sum up all purchases and sales and corrections every time (and never being able to delete old transaction data from the database, as that would invalidate the calculations).
However there are reasons to have stock stored in an inventory table instead. For instance if you want to store different statusses, e.g. you have 100 pieces in store plus twenty just arrived and still unchecked. Or you have a store with goods plus a warehouse housing additional stock. Or you have charges (different model numbers for example for a slightly altered product) which you offer as the same product, but still want to know how many old and how many new ones are in stock. And so on.
So make your mind up, if you want to store additional data with product stock, which would result in an 1:n relation instead of 1:1 which you have now.