Merge Portfolios from CZ/EZB and NZ/ZDB records fka. Redo NWBIB Collection Mapping for electronic resources/ZDB

[TobiasNx]

ZDB records are part of the HBZ Union catalogue. They are genuin hbz records in the NZ.

But for electronic resources not the hbz record is relevant but the CZ entry which is replicated in the NZ too. Only the EZB resources of the ZDB are part of the NZ.
These create duplicates.

These duplicates are technically needed at least until all libraries are migrated to ALMA or using ALMA-Data. Especially the bridges are using the CZ/NZ Publications. Ultimately the hbz ZDB entries will be deleted or be deprecated.

We need to do the following:

1. We need to exclude the NZ NWBIB electronic resources which are part of the NZ but are (not part of the CZ - OR - not part of the EZB) from NWBIB collection.
2. We need to include the CZ/NZ NWBIB electronic resources and keep the NZ/EZB/ZDB electronic resources.

Questions:
Are the EZB electronic resources also part of the CZ and have 035 __ $$a (CKB)...?
Are there electronic resources that are neither part of the CZ, EZB or ZDB that are part of the nwbib and do they need special treatment?

[TobiasNx]

We are not sure yet how to handle this problem.
One solution could be to merge the records of CZ/EZB and NZ/ZDB. Use the NZ/ZDB-Record as master and only add the holding perhaps more from the CZ record. Also add the AlmaMMSId of the CZ/EZB-Record to sameAs.

For that we woud need a shared identifier. And find out how to handle this with elastic search. This might be solved with: https://www.elastic.co/guide/en/elasticsearch/reference/current/docs-update.html#scripted_upsert

[TobiasNx]

Another solution could be: https://discuss.elastic.co/t/merging-documents-based-on-matched-fields-values/249728

I talked to S.S. from Verbund-Gruppe. She said that only Holdings(Portfolios), the link to AlmaMmsId and the CKB Number are relevant from the CZ/EZB/CKB records. All other information could be used from the NZ/ZDB record.