Postcode information is held separately to enable analysis of addresses at different levels, and geomapping. 

The records are mostly taken from the ONS (Office for National Statistics).  Full details of where the data comes from, and how to load the postcode data are in the Technical Documentation.

The columns are as below:

Column Name Data Type Description Derivation
postcode_single_space varchar The full postcode with a single space between the first and second part  
postcode_8char/ 7char char The full postcode with a variable number of spaces in the middle.  The last character is position 8/ 7 respectively.  
postcode_area char The first 2 characters of the postcode.   
postcode_area_longitude/ latitude char (Is actually a number) The longitude and latitude of the area, to enable display via mapping software.  
postcode_country varchar Whether England, Scotland, Wales or Northern Ireland  
postcode_district (latitude) varchar The part of the postcode before the space.  
postcode_district_longitude/ latitude   As for postcode_area longitude and latitude  
postcode_msoa varchar Middle Layer Super Output Area.  
postcode_nuts3 varchar Slightly more detailed level than county.  County information isn't complete, being not populated for metropolitan areas such as Birmingham and London.  Holds for example Norfolk and Suffolk, but also 'Inner London - East' and 'Inner London -West'.   
postcode_region varchar High level categories, such as 'East of England', 'South East', South West'  
postcode_sector varchar Up to the first character of the second part of the postcode, eg 'NR32 4  
'.postcode_sector_longitude/ latitude varchar The most detailed level held, to enable accurate analysis of geographic data.  
postcode_longitude/ latitude varchar The data is not sufficiently populated to use this.  Tableau holds the data itself.  
postcode_within_12_mile_radius varchar As name Specific values entered.  Was used for assigning accommodation, less required now.