# Dataset metadata

The sub-pages in this section define dataset metadata for the **CSV format** of OS Emergency Services Gazetteer (OS ESG) data:

* [Header (Type 10 Record)](https://docs.os.uk/os-downloads/products/addresses-and-names-portfolio/os-emergency-services-gazetteer/os-esg-technical-specification/dataset-metadata/header-type-10-record)
* [Metadata (Type 29 Record)](https://docs.os.uk/os-downloads/products/addresses-and-names-portfolio/os-emergency-services-gazetteer/os-esg-technical-specification/dataset-metadata/metadata-type-29-record)
* [Trailer (Type 99 Record)](https://docs.os.uk/os-downloads/products/addresses-and-names-portfolio/os-emergency-services-gazetteer/os-esg-technical-specification/dataset-metadata/trailer-type-99-record)

The attributes associated with each data type are listed on the following pages. The following information can be found about each attribute:

### Name and Definition

The name of the attribute and what it is describing.

### Attribute Type

The nature of the attribute (for example, a numeric value or a code list value).

### Size

The maximum length of the values in the attribute.

### Nullable

A True or False value to denote whether the attribute always has to be populated with a value (False) or can be NULL (True).

### Data Schema Version

The schema version the data above applies to.