hello, I have some LDM issues in the web UI - not ...
# gd-beginnersj
Jamie Lawrie
11/14/2023, 3:17 AMhello, I have some LDM issues in the web UI - not getting much feedback on why I can’t link things I think I should be able to link so coming here. Details in thread
Jamie Lawrie
11/14/2023, 3:17 AMimage.png
Jamie Lawrie
11/14/2023, 3:18 AMI have a primary key (service id) on 2 tables. One is a lookup being used for a filter (and includes historical services) the other is live services.
Jamie Lawrie
11/14/2023, 3:18 AMimage.png
Jamie Lawrie
11/14/2023, 3:20 AMIn my head I have two tables with a unique list of service ids on each and I just want to filter one by the other. When I attempt to join them by service id it just won’t let me - instead showing the ‘connect as new field’ option above
Jamie Lawrie
11/14/2023, 3:21 AMI feel like I am missing some important underlying GoodData logic here because Power BI and Quicksight would just let me join things like this quite happily (it is in effect a simple inner join) so there must be some hidden gooddata rule that isn’t being exposed to me via the UI
Jamie Lawrie
11/14/2023, 3:25 AMJamie Lawrie
11/14/2023, 3:26 AM^^^ this worryingly seems to suggest I can only create a connection between a primary key and a foreign key
Jamie Lawrie
11/14/2023, 3:31 AMIt would suggest that to make GoodData work I have to create one master service table outside of gooddata and feed that in so it only has one table that ever has service_id as a primary key.
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Jakub Sterba
11/14/2023, 6:25 AMHi Jamie, I have bad and good news.
bad news: currently there is a limitation that after you connect datasets using 1:N relation, you cannot set referenced attribute (foreign key reference in Services dataset in your case) as primary key of the dataset. Therefore the connection dialog suggests to create new “field” for such relation instead of using Service id attribute which is already present in :Services dataset. You can do it and map it to the same source column in the Services table. You will end up with two Service Id attributes in logical model (one contained in Service id lookup and other in Services dataset) as is currently the case in your model anyway, but the datasets will be connected so you will be able to use attributes from both in the same insight.
But I have also good news: a feature is coming which will let you use composite primary keys and composite key references. This feature will also let you set primary key consisting of reference to attribute in other dataset. It will be possible to set Service id column in Services dataset as reference to primary key attribute in Service id lookup and as primary key of Services dataset at the same time once this feature is delivered. Note that you are using two Service Id attributes so if you want to have only one in your data model, it will be better to connect datasets using the new field first (as is currently possible) then go through insights/metrics/dashboards which use Service Id attribute from Services dataset and replace them with Service id from Service lookup datasets before you remove the Service id attribute in Services dataset. You can edit title of the attribute in modeler to differentiate them better in data catalog.
Public release of the composite keys in GD CLoud is planned for the end of November, but you may contact support to have a early access after release which is planned for this Thursday. Watch release notes.
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Jamie Lawrie
11/14/2023, 7:37 PMok thanks for the detailed response. Ultimately, we should have designed the structure to have one combined lookup so we are fixing that on our side which should allow us to get the result we desire anyway. Good to know there is more flexibility being added to the product