Manage a Logical Data Model
Data modeling in GoodData revolves around the concept of a logical data model (LDM). You create and modify an LDM for a particular workspace using our fully integrated LDM Modeler. Go to Logical Data Model in GoodData - Introduction article to learn why LDM is so valuable.
LDM represents the relationship between data objects in a workspace. The LDM provides a layer of abstraction so that you do not have to interact directly with the relational model of your database using SQL. The relational data model is represented by physical data model (PDM) in GoodData.CN. Go to Data Sources - Physical Data Model, if you want to learn more about PDM.
In the LDM Modeler, you assemble:
- Datasets with Attributes (with Labels) and Facts
- Primary keys of data sets and Relations between them
- Date dimensions
- In GoodData.CN date dimensions are virtual datasets with relations to standard datasets. There relations point to DATE/TIMESTAMP columns in those standard data sets. All the date arithmetic is calculated on top of these columns.
Go to Objects of the Logical Data Model to learn more about all LDM objects.
GoodData.CN is designed to enable users to quickly create and modify LDMs and publish them into workspaces. However, be careful in how you assemble the components of your LDM. When possible, deploy experienced modelers to your workspaces, particularly if they involve multiple interacting datasets or specialized use cases for your data.
If you are new to BI data modeling, invest time and effort to study data modeling practices prior to implementing a production GoodData solution.
Read the following two articles to learn more about how to create a good LDM:
Info
GoodData.CN is directly integrated with your databases. LDM is directly mapped to PDM, which represents relational model of your database. When you prepare ideal LDM, you may realize that mapping to the PDM is not possible. In this case we strongly recommend introducing a new ETL process, which materializes relational model, so corresponding PDM is aligned with the LDM.
Additionally, LDM can be inherited and distributed into child workspaces, you can learn more in Build a Workspace Hierarchy.
Warning
As of now it is not possible to edit LDM in child workspaces. You can see the model there (inherited from parent), but you cannot edit it.