Hey! Quick question on PDM/LDM change management i...
# gooddata-platformp
Philippe Hébert
02/02/2022, 8:45 PMHey! Quick question on PDM/LDM change management in GD (hosted):
Given a pre-existing star schema in the source data, with a predefined set of tables & columns,
When said tables or columns will be modified in the future (change of name, change of type, etc),
Then will I be able to map the LDM to the new PDM easily (assuming same structure, just different names/types)?
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Michal Hauzírek
02/02/2022, 9:00 PMYes, if you are loading data with the Automated Data Distribution V2 (from cloud datawarehouse) then the mapping to the tables and columns in your database is part of the Logical Data Model and you can change it.
To do so, open the dataset detail in the Modeller and click on the “Load Configuration” tab. There you can define the table (top right corner) and for each object also the column from that table to use.
Regarding migrating this mapping between workspaces, please note that this mapping configuration currently does not get transferred between workspaces if you clone a workspace. But even then can transfer it by manually exporting the model to JSON from one workspace and importing it to another in the Modeller. Also the Lifecycle Management using the Bricks transfers the mapping changes automatically.
Michal Hauzírek
02/02/2022, 9:01 PMRegarding the change of datatype - in that case you might also need to change the data type in the Logical Model itself as well (depending what you are changing). The tool performs a validation during the load and if for example you would change the source type for a fact to varchar, it would fail.
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Philippe Hébert
02/02/2022, 9:06 PMGreat, thanks Michal 🙂
Regarding migrating between workspaces, does this note also affect parent->child workspaces or only cloned workspaces?
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Michal Hauzírek
02/02/2022, 9:52 PMIf by parent->child you mean the Lifecycle Management which exists in the hosted solution, then it depends with which tools are you managing it.
If you are using just the APIs, then yes you need to do this model mapping migration.
If you are using the GoodData LCM Bricks (basically orchestrating tooling on top of these APIs) you are covered and they will distribute also the mapping changes for you automatically.
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Philippe Hébert
02/04/2022, 1:24 PMNice, thanks @Michal Hauzírek! I am currently going through the docs to better understand said LCM & Bricks
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Michal Hauzírek
02/04/2022, 1:51 PMGreat. Maybe this sheet can help explain the role of individual LCM bricks in the whole context.
And just a note not mentioned there - you can use LCM and bricks also with only a single domain, (release from one domain to the same), but it is recommended to have a separate development domain.