# Supply and update

AddressBase Premium Islands is supplied as non-geographic chunks only. This is a way of dividing up the data into chunks that are supplied in separate volumes, which have a fixed maximum number of records. The supply is not supplied with any reference to the geographic position of records.

Customers are able to take the AddressBase Premium Islands product as a full supply or a change only update (COU) supply for GML and CSV formats. The AddressBase Premium Islands GPKG is available as a full supply only.

## **Unzipped files**

{% hint style="info" %}
A file size limit might be imposed by the file system to which the file is written.
{% endhint %}

When you receive your data, the filename will be constructed as follows:

* *productDescription\_supply\_ccyy-mm-dd\_vvv.format* 
  * **productDescription**: `AddressBasePremium_ISL`
  * **supply**:  `FULL` or `COU` 
  * **ccyy-mm-dd**: the date the file was generated
  * **vvv**: volume number of the file
  * **format**: file format of the files received, for example `csv`, `gmlL` or `gpkg`

For example:

* `AddressBasePremium_ISL_FULL_2015-10-28_001.gml` (GML full supply)
* `AddressBasePremium_ISL_COU_2015-10-28_001.csv` (CSV COU supply)
* `AddressbasePremium_ISL_FULL_2015-10-28_001.gpkg` (GPKG full supply)

## **Zipped files**

If the data has been provided in a ZIP file, the filename will be constructed as follows:

* *productName\_supply\_ccyy-mm-dd\_vvv\_format.zip* 

For example:

* `AddressBasePremium_ISL_FULL_2013-05-28_001_gml.zip` (GML full supply zipped)

## COU supply

AddressBase Premium Islands is available as a full or change-only update (COU) supply for CSV and GML formats. COU supplies are not available for GeoPackage format.

A COU supply of data contains records or files which have changed between product refresh cycles. The primary benefit in supplying data in this way is that data volumes are smaller, reducing the amount of data that requires processing when compared to a full supply.

COU data enables a user to identify three types of change:

1. Deletes (CHANGE\_TYPE ‘D’) are objects that have ceased to exist in your area of interest (AOI) since the last product refresh.
2. Inserts (CHANGE\_TYPE ‘I’) are objects that have been newly inserted into your AOI since the last product refresh.
3. Updates (CHANGE\_TYPE ‘U’) are objects that have been updated in your AOI since the last product refresh.

### Archiving

When users are deleting, inserting or updating features, it is up to the user to consider their archiving requirements. If deleted records are important to your business requirements, you must take appropriate action to archive previous records.


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