Code History Database (CHD)

The CHD provides details of individual codes, relationships, hierarchies and archived geographies and their metadata. The database provides multi-functionality and enables you to view or export data for the following options:

• ‘Geography Listings’ contains both terminated and live entities, and instance codes, for geographies where new codes are available

• ‘Geography History’ contains the change history, where new codes have been allocated, from 1 January 2009

• ‘Geography Hierarchies’ provides the hierarchies for all entity themes where a one-to-one relationship exists

• ‘Geography Constitutions’ are provided for some geographies in England and Wales. These include parish to ward, electoral and health constitutions

• ‘Geography Equivalents’ provides the new codes and previous ONS, CLG, DH and other equivalent names and codes where available

• ‘Geography Information’ contains information about the geographies including Statutory Instrument Information

You can find further information about the geographies within the CHD in the A Beginner's Guide to UK Geography.

Product details

The CHD is available in MS Access 2007 and 2002 format.

If you don’t have MS Access, there are csv name and code and lookup files available to download free of charge from the Open Geography portal. These files are supplied with metadata, product specification and any other associated documentation in one zip file.

Availability

The current MS Access zip file and csv zip files are available and you can download them free of charge from the Open Geography portal.

Please save the CHD to your hard drive to ensure you have access to complete database functionality.

Please note that you may experience slow download times when trying to open the files because of the size.

N.B. If you are using MS Access 2007, an ‘Information’ bar appears, warning that certain content in the database has been disabled. To rectify this, click on the ’Options’ button next to the warning message and then the radio button 'Enable this content'. To enable the export of data from the CHD, click the drop down arrow located to the right of the ‘Office’ button (top left of screen) and select 'Customise the quick access toolbar'. Select the 'More commands' option and 'Export to Excel spreadsheet' or your preferred alternative.