Sustainability of Digital Formats: Planning for Library of Congress Collections

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dBASE Table for ESRI Shapefile (DBF)

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Format Description Properties Explanation of format description terms

Identification and description Explanation of format description terms

Full name dBASE Table for ESRI Shapefile (DBF)
Description The dBASE table (.dbf) file is one of the three files required for a valid ESRI Shapefile. In addition to a file containing the dBASE table, instances of the ESRI Shapefile format must include a main file and an index file, and may include several others. The dBASE table file contains feature attributes with one record per feature. The one-to-one relationship between geometry and attributes is based on record number. Attribute records in the dBASE file must be in the same order as records in the main (.shp) file. The dBASE table (.dbf) file cannot exceed 2 GB, thus allowing approximately 70 million point features at most.
Relationship to other formats
    Component of ESRI_shape, ESRI Shapefile
    Subtype of DBF, dBASE Table File (DBF). ESRI Shapefile (DBF) .dbf files are in dBase format

Local use Explanation of format description terms

LC experience or existing holdings  
LC preference  

Sustainability factors Explanation of format description terms

Disclosure The Shapefile dataset format was developed by ESRI as an open GIS format, and uses as its table format for structured data a dBASE Table File (DBF) that is based on versions of dBASE format in use when the Shapefile was introduced. dBASE is a well-documented format.
    Documentation See DBF for general documentation for the dBase Table format. The Shapefile format, including the constraints on the dBASE Table File for use in a Shapefile, is defined in ESRI Shapefile Technical Description, July 1998. The description of the .dbf file is on page 25.
Adoption See ESRI_shape.
    Licensing and patents See DBF.
Transparency See DBF.
Self-documentation See DBF.
External dependencies  
Technical protection considerations  

Quality and functionality factors Explanation of format description terms

GIS images and datasets
Normal functionality The functionality of the dBASE file format versions used for the ESRI Shapefile format is limited in terms of describing or performing calculations upon attributes. These limits include the format's inability to store null values, the maximum length of field names set at 10 characters, the maximum number of fields set to 255 (thus limiting support for Unicode), and the storage of floating point numbers as text (thus introducing possible rounding errors). There are other limits in play regarding the types and character widths of the data-field types that are supported. ESRI provides a complete and candid overview in its online help document titled "Geoprocessing Considerations for Shapefile Output."

File type signifiers and format identifiers Explanation of format description terms

Tag Value Note
Filename extension dbf
Database formatting for feature attributes based on earlier versions of dBASE (IV, V)
Internet Media Type application/dbf

Notes Explanation of format description terms


Format specifications Explanation of format description terms

Useful references


Last Updated: 02/27/2017