SAP s/4hana new simplified data model (NSDM) model introduction

SAP ERP Central Component( abbreviation ECC) Inventory management data model , It is based on the material document (Material Document)、 Mixed table (Hybrid Table)、 Aggregate table (Aggregation Table) And history table (History Table) Above .

These tables store some redundant information , It is used to return various query requirements to the application .

A large number of tables in the data model , It often leads to low performance of inventory related reports , Because in order to display the material inventory value , We must extract information of various dimensions from these tables . On the other hand , When dealing with the tables of the old data model ,UPDATE The database lock caused by the operation may conflict with another lock from the business operation .

In order to solve SAP ECC These limitations of , stay S/4HANA A new simplified data model is designed based on the following premise (New Simplified Data Model, abbreviation NSDM):

• All inventory data will be calculated from important document information stored in a single table , And this table only supports INSERT Operation management . Through dynamic calculation of material inventory information , It solves the problem of data redundancy .

• Use a single material document table , Solved the problem of low reporting performance .

• Because it is only used in the material document table INSERT operation , The lock problem has been solved .

S/4HANA Specific implementation ideas in ：

• Use CDS Proxy objects in the form of views . Used to dynamically calculate inventory data , And connect the master data results contained in the hybrid table .
• If a given hybrid table has a proxy assigned to it , Of this table SELECT Statement will be in the database interface layer (Database Interface Layer) Redirect to the specified CDS View .

Dynamically calculate the value of inventory , Obviously, it is slower than getting the aggregated data directly from the aggregation table . In theory , The calculation performance of inventory value is directly proportional to the number of records in the material document table . To solve this performance problem ,SAP S/4HANA Used as MATDOC The second table of the table subset , namely MATDOC_EXTRACT.