For any library storing MARC Bibliographic records in Source Record Storage (SRS), FOLIO contains a default MARC-to-Instance map. FOLIO uses that map when creating or updating Inventory Instances with Source = MARC. The map identifies the Instance fields that are controlled by the underlying MARC Bibliographic record, and which fields and subfields of MARC data populate into which Instance fields. Occasionally libraries may adjust their default map, either because of 1) updated default mappings delivered in a new FOLIO release or 2) local fields or mapping decisions that differ from default map. When a library's default map is updated, those updated mappings will affect any Instances created or updated after the map change. However, some libraries would like to update all of their existing Instances to reflect the updated mappings. This script allows for that to happen. 

NOTE: Add some info about how the script works, approximate timing, when to run it so as not to interfere with regular library operations

Examples of library-specific mapping changes:

• Add a mapping for the previous system's legacy bib ID. Usually it's something like a 9xx field (e.g. 907$a) mapping to a special identifier type (defined in Inventory Settings)
• Include 690 fields in the Instance subjects

!!! This Instance update Postman collection may affect performance of other imports, so it needs to be used during non-working hours or during off-peak hours !!!

Before launch Postman collection you need to set up environment:

• click on "eye" button and press "Edit/Add" on "Environment" variables
  
• Name environment as you want and put these mandatory variables:
  protocol (http/https), url (your library okapi url), username (admin user name), password (admin user name password), xokapitenant (admin tenant).
• There are also optional parameter "limit" to limit number of instances to parse. Both sources are counted (FOLIO/MARC), but only MARC source types will be processed.
• After setting up all the environment variables press "Reset all" and then "Save"
  

1. Import collection by pressing "Import" button 
   
2. Select collection file (Update MARC to Instance map.postman_collection.json) file from folder or drag it into opened window and then press "Import" button.
   
3. Go to the "Collections" tab and select "Update MARC to Instance map"
   
4. Then select environment you'd set up
   
5. To launch collection press "Run" button below environment selection and in the opened window press "Run Update MARC to Instance map"