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title: "APPENDIX"
canonical: "https://docs.vaultspeed.com/space/VPD/3133046876/APPENDIX"
format: markdown
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1. Links and Many to Many Links in VaultSpeed In the hands-on session we talk about links and Many to Many links. This section explains the difference between them. 1.0 Normal Link A “0-1 to N” relationship or “0-1 to 1-0” relationship will become a  link table  in the Raw Data Vault. The internal short name Prefix for a link table is :  LNK The internal short name Prefix for a Satellite on link is :  LKS   1.1 Many to Many Link The relationship table in the Raw Data Vault that results from a  M-N relationship  on the source is called a  Many to Many Link . It needs to be differentiated from a link based on a 1-1 or 1-N relationship, because it can hold attributes which results in  different ELT The internal short name Prefix for a Many to Many link table is :  LND The internal short name Prefix for a Satellite on Many to Many Link is :  LDS   2. Primary/Secondary data VaultSpeed uses some terminology concerning the topic of Master data in an organization. The following sections elaborate on this topic. 2.0 HUB Primary-Secondary Relationships When defining a Primary-Secondary relationship between 2 sources, it means, as shown in the picture, that : Source1, which is the Master Data Owner will be used to load the HUB and the Satellite related to Source1. Source2, that gets it’s data copied from the Master Data Owner on the source, will be used to load the Satellite related to Source2, the secondary source. The reason why there are still 2 Satellites is that in our experience, additional fields can be present in the secondary source, making it necessary to create 2 separate Satellites.     2.1 HUB Primary-Primary Relationships When defining a Primary-Primary relationship between 2 sources, it means, as shown in the picture, that : Source1, which is a Master Data Owner will be used to load the HUB and the Satellite related to Source1. Source2, which is a Master Data Owner will be used to load the HUB and the Satellite related to Source1. The data is partitioned by row across the source systems, by adding the source system name to the key on the picture the SRC-Attribute. This is needed because the same descriptive data can have a different key in the different source systems. In the example is the code CD12 linked to key 1 in Primary Source 1 and linked to Key 5 in Primary Source 2.