Designing an LDM – Logical Design Model
I would like to share my views and understanding on LDM – Logical Design Model, helpful while developing a Project.
Logical Design Model
In the process of initiating a Project, one of the important document is LDM. Here I would like to share the basic steps followed by most of the clients to prepare a TDD and also the importance of this Model.
The LDM would help the consultants to start technically working on the SAP System to build required Project.
Most of the times, this LDM can be in designed in MS VISIO or any designing tool.
Overall LDM can be divided into certain Layers
· Data Sources
· SAP BW Extractors
· SAP BW Staging Layer Data Repositories
· SAP BW Information Layer Detail & Summary Information
· SAP BW Reporting Layer
This will be the bottom layer showing all the data Sources, ECC, NON-SAP Files etc showing the connectivity to the upper layer.
SAP BW Extractors:
The connectivity of data sources with any intermediary tools like BODS etc will be shown in this layer. In this layer the Extractors are shown diagrammatically with showing the data loads – Full Load or Delta Load.
SAP BW Staging Layer Data Repositories:
In this layer, the Staging Layers are depicted through pictures, most of the times DSO, characteristic InfoObject. The DSOs are identified with Ricef numbers.
SAP BW Information Layer Detail & Summary Information:
The lookups or Master Data Attributes, Texts and Hierarchies required are listed in this layer. This is the layer where the CUBEs are shown with their respect names. Here there are all the details mentioned which are required to create the links between multiple cubes with multiple DSOs.
The structure of the linkage is shown to understand the tracking of data between DSOs to InfoCubes. Customer,Vendor,Material,Sales person,Sales Org,Sub Entity, Country, Biz Country are updated.
SAP BW Reporting Layer:
Multiproviders are the important views shown in this layer. Reporting layer forms an important layer in client perspective. Most of the tools available for reporting are Query Designer, Connection JCo/ BICS, Data Foundation, Business Layer, Universe, WEBI.
Sample LDM Showing all the layers:
These LDMs played a very important role in our Projects thus wanted to share this with everyone.