Glossary

Table Types

• Extraction table: A table storing all data extracted from a source. This is the input for the framework.

• Staging table: The table created from the extraction table and containing all DV specific fields used to load every target table (hubs, links and satellites).

• Hub: Table that keeps record of all distinct business keys of a specific entity.

Example

Hub Customer will have one record per customer.

• Link: Table that keeps record of all distinct relationships between one or more hubs.

Example

Link Customer Activity will store one record per relationship between Customer and Activity.

• Satellite: Table that contains all properties of a link or a satellite. The data in this table is totally historized. Each row has a start and end timestamp. If a change is detected, a new record is inserted and the start and end timestamps adjusted accordingly.

  • Effectivity Satellite: A special type of link satellite, that defines which link relationship is active at a given point in time, based on a subset of link fields.

Example

Let’s imagine Link Customer Activity presented in Link table example above. If we would want to keep just the latest activity performed by the customer as active (open version in the satellite) we would need an effectivity satellite, with h_customer_hashkey defined as driving_key.

Field Types

• Business key: Operational identifier of an entity.

Example

customer_id.

• Child key: A field that exists in the source system, is not a business key, but is used to define a relationship between two entities.

Example

A link between a Customer and an Activity may have a timestamp that represents the time in which the customer started doing that activity. If a customer does the same activity three times a day, we record three relationships. If we did not have this field as child key and the Customer would do the same activity during a whole month, we would record one new relationship in that month.

• Hashkey: generated identifier, equivalent to a hashed version of the table business keys.

Example

h_customer_hashkey will correspond to an hashed version of customer_id, and will be used as primary key of Hub Customer (h_customer).

• Hashdiff: generated field, equivalent to a data row identifier (hashed version of all business keys + child_keys + descriptive field). This field is used to identify which records were changed between loads.

• Metadata: Fields that represent Data Vault specific metadata: for now, the three fields defined as metadata are the following:

  • r_timestamp: start timestamp of a record.

  • r_timestamp_end: end timestamp of a record (only applicable to satellites).

  • r_source: source system (API/database/etc).