---
title: "HUB"
canonical: "https://docs.vaultspeed.com/space/VPD/3010723917/HUB"
format: markdown
---
After Locking a Release (the little padlock symbol at the end of the release is closed, but the status is still a ‘WORK IN PROGRESS’) and clicking on the release, the tabs for **HUBS and SAT Splitting **are revealed. 

Here we will have a look at the HUB settings.

### Single/Multi-Primary Hubs 

Defining a HUB as Multi-Primary will add the ‘source system business key’ attribute (default attribute name = SRC_BK) to the HUB and include this key also in the Hash Key Calculation. The Content of this attribute is defined when setting up the source (field: Source System Business Key').

Defining a Hub as Multi-Primary is necessary when different sources use one Hub (which you can group later on in the Data Vaults → Hub Management screen) and there is no guarantee that the same Business Key has the same meaning in the different sources, or when there is no source which is the Primary and contains all keys.

E.g.: HUB_EMPLOYEES is used by different Sources, but EMPLOYEE_ID = 1234 in Source X is not the same person as EMPLOYEE_ID = 1234 in Source Y. By defining the Hub as Multi-Primary 2 Hub Records will be created:

```
HASHKEY   SRC_BK    EMPLOYEE_BK
OP0I..    X         1234
I4NC..    Y         1234
```

This rule is also applied if you have multiple objects within one source that you will group together.  In that case, VaultSpeed will automatically add the ‘object short name’ to the ‘source system business key’ to keep the records unique.

E.g.: HUB_EMPLOYEES and HUB_WORKERS both come from source X and both contain employee data.  But EMPLOYEE_ID = 1234 from HUB_EMPLOYEES is not the same person as WORKER_ID = 1234 in HUB_WORKERS. By defining the Hub as Multi-Primary 2 Hub Records will be created:

```
HASHKEY   SRC_BK        EMPLOYEE_BK
LIP9..    X_EMPLOYEES   1234
NJ8Y..    X_WORKERS     1234
```

A combination of the two above cases is, of course, also possible.  This would result in the following records in your HUB object with the types of the objects set to multi-primary:

```
HASHKEY   SRC_BK        EMPLOYEE_BK
LIP9..    X_EMPLOYEES   1234
NJ8Y..    X_WORKERS     1234
I4NC..    Y             1234
```


If you set your HUB as a Single-Primary object, the ‘source system business key’ attribute will not be added to your object.

By default, VaultSpeed will define all hubs as Multi-Primary.

![image](media://0e67a8da-1e6b-4950-ba24-066c937197ea)


The Hub type can be set one by one using the edit option at the end of every line, or by using the general HUB Type slider at the top in combination with a search.

Don’t forget to save the changes when you are done.