I am a step-by-step code to complete the (12) inventory of Wanang.com 1. Overview

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< strong> 　　Wancang.com’s ERP system is not open source. We are going to make a series to talk about the main technical points. These technical points will have source codes. If you want to see all the source code of , you can go home, there is no need to read it anymore, and waste your precious time. strong> strong>

　　The next few articles begin to talk about Speaking of inventory, how to design an efficient NB e-commerce inventory system? What are the main points of a good e-commerce inventory system?

　　 For users, of course, it is easy to operate; inventory accounts are clear and accurate; it can reduce oversold during the double 11 and 618 promotion; it can predict future sales based on existing inventory sales data , Control the supply chain, improve inventory turnover rate and capital utilization rate.

　　 For development and design, what can be done to meet user requirements? Of course, it is to directly learn from a mature and large-flow e-commerce inventory system, that is, Amazon’s Bin system. There are many introductions to the Amazon bin system on the Internet. You can search for keywords for inquiries. I won’t introduce too much here, just go to the text. .

　　1. Adopting a dual inventory structure, the first level is an inventory structure with warehouse and SKU as the dimensions. The main fields include warehouse code, SKU code, orderable quantity and inventory quantity, etc. (can be based on this For example, the orderable quantity of defective products, the inventory of defective products, and the locked quantity of order (the inventory locked before the big promotion) are expanded on the above. Here, we only introduce the extended fields, only the quantity of genuine products and the stock of genuine products).

　　 can The order quantity is the quantity available for orders (including transfer orders, requisition orders, purchase return orders, etc.). After the order enters the ERP system for confirmation and review, the orderable quantity is deducted according to the order details. At this time, the inventory quantity remains unchanged. This design can ensure that the oversold phenomenon is reduced during big sales promotion. The system can judge whether an order can be placed according to the orderable quantity, and the orderable quantity may be negative when the inventory is in deficit.

　　 Inventory is the actual commodity inventory in the warehouse, and the inventory cannot be negative.

　　2. Bin inventory structure with dimensions and SKU as dimensions on the second level. The warehouse has shelves, and each shelf on the shelf is called a “Bin” position, which is useful for the warehouse’s work The staff has a little more workload, and it is necessary to set the cargo space in advance, and the length, width and height of the cargo space can be set more carefully. When the goods are in the warehouse, the shelves can be recommended according to the volume of the goods.

　　货The tag number needs to be unique in the entire system, so that it can be easily located and retrieved.

　　 There are three types of storage space according to the type of goods in stock and the way of use: genuine storage space (subdivided into genuine storage space and genuine picking space), defective goods storage space and mobile storage space. The genuine product slot can only store the genuine inventory, and the defective product slot can only store the defective product inventory. The mobile cargo space is a special cargo space. For example, when the purchase order is put into the warehouse, the purchased goods should be placed on the pallet according to the warehouse operation. At this time, the pallet is the mobile cargo space, and the warehouse manager pulls the pallet to the genuine product. The cargo slot or the defective product slot is put on the shelf, so that the cargo slot is bound to the SKU, and then BinItem (stock slot inventory) is derived.

　　 You can take a look at the table structure of BinItem. One storage space can hold multiple SKUs. This design prevents one SKU from occupying one storage space. When there are too many types of SKUs, the storage space is not enough. Can reasonably use the cargo space.

　　 The available quantity is the quantity that can be sorted. Take the order as an example. When the order occupies the orderable quantity in the Storage table, it needs to sort the specific goods position. Sort according to the status of the receipt. Genuine goods or defective goods positions. When sorting the goods position, the BinItem table ForUsage is directly deducted (logging is required, and the goods are picked according to the designated goods position when picking), but the inventory of the goods position remains unchanged.

　　 Take a purchase order as an example. The document must be distinguished from the source whether it is genuine or defective. Of course, the purchase order must be genuine (some second-hand merchants will purchase some defective products). When the purchase order is put into the warehouse, The storage inventory table can be ordered and the inventory should be increased together, and users can place an order on the shopping website. At the same time, the inventory of the BinItem inventory table of the mobile position should increase, and the usable quantity of the mobile position need not increase. WHY? Because of the system setting, the document can not be sorted to the mobile position when picking (the document is picked from the genuine goods position to the mobile position, then the document is sorted to the mobile position, resulting in an infinite loop), then it can be used When will the amount increase? When the inventory is put on the shelf, when the inventory of the cargo space is moved from the mobile cargo space to the genuine (defective) cargo space, the available quantity of the genuine (defective) cargo space and the inventory of the cargo space increase at the same time, and the inventory of the mobile cargo space is deducted. No operation is performed on the Storage table.

　　 It can be seen that the orderable quantity of the Storage inventory table and the available quantity of the BinItem inventory table are not consistent in real time. The order occupies the orderable quantity, and the available quantity is not occupied when it is not sorted. However, the inventory of the inventory table and the inventory table of the goods location are the same.

　　 The inventory of both must be increased or decreased at the same time when entering or leaving the library, which requires extremely high system consistency, and transactions can be used reasonably to ensure the consistency of the operations of the two tables.

　　The inventory system designed in this way can realize refined management. In which position, inventory, orderable quantity and available quantity of a certain commodity can be easily inquired, due to the BinItem table structure design, when When there are many SKUs or cargo positions, one SKU can be placed in multiple cargo positions, and there are frequent movement of the cargo positions, the amount of data will be relatively large, the index key needs to be set reasonably, and the reading and writing pressure on the database is also relatively large. Of course, there are many benefits. The warehouse can be equipped with some modern PDAs to realize paperless operation, and the warehouse can operate at the same time for picking, putting on shelves and counting.

　　 唠唠叨叨, let me talk about so much first.

PS: The guest officer has time to visit my station Wancang.com.