Date field

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EPrints 3 Reference: Directory Structure - Metadata Fields - Repository Configuration - XML Config Files - XML Export Format - EPrints data structure - Core API - Data Objects

Metadata Fields: Arclanguage - Base64 - Bigint - Boolean - Compound - Counter - Dataobjref - Date - Decimal - Email - Fields - Float - Id - Idci - Image - Int - Itemref - Keywords - Langid - Longtext - Longtext_counter - Multilang - Multipart - Name - Namedset - Pagerange - Recaptcha - Recaptcha3 - Relation - Search - Secret - Set - Storable - Subject - Subobject - Text - Time - Timestamp - Url - Uuid


This field is used to store a single date. Internally EPrints always uses ISO standard notation for dates, it avoids confusion. This is YYYY-MM-DD.

In bibliographies sometimes exact dates of publication (or other events) are not known. EPrints allows you to store month and year values in date fields. YYYY or YYYY-MM.

In the database EPrints actually uses 3 integer fields to store the date, rather than a built in date field. This is because of the need to allow NULL in month and day if the date is just 1998.


Additional Properties

Name Default Value Required Description Notes
input_style long NO Whether to render the date inpit fields using longer or shorter month labels. Can be short or long. The former is useful if you have limited width in your input form, especially if you are using a date field in a Compound field.
min_resolution day NO The minimum resoltion of date that must be entered. Can be day, month or year. If set to day then values of YYYY or YYYY-MM will cause a validation error. If set to month then values of YYYY will cause a validation error. If set to year then day, month or year resolutions are allowed.
render_res day NO The resolution to render the date stored by this field. Can be day, month or year. If set to year then the dates 1998-10-01, 1998-10 and 1998 would all be rendered as 1998. This is not too useful in configuring the field, but can be set as a print option inside citation files.
render_style long NO The resolution to render the date stored by this field. Can be short, long ordow. If long then you'll see 8 September 1998. If short then 08 Sep 1998. dow would render Tuesday 8 September 1998.

Required Phrases

No additional phrases beyond the standard metadata field phrases.


Date fields are stored in the database as:

fieldname_year SMALLINT(6)
fieldname_month SMALLINT(6)
fieldname_day SMALLINT(6)

If a date only has a year value then it would be stored as 1998,NULL,NULL


See API page.

Date values are represented in the API as scalars containing ISO encoded dates. eg.



Date fields can be searched as either single values or ranges. Searching for 2006> will also match 2006-12-25. You can search for 2000- to search dates in or after 2000. Or 2000-12-2003-01 for December 2000 through January 2003.


Most basic example.

    name => 'acceptance_date',
    type => 'date',

Set minimum resolution to which the date must be specified is at least a month.

    name => 'moratorium_date',
    type => 'date',
    min_resolution => 'month',

Set resolution to render to the month, set rendering style to short (e.g. Feb 2023).

   name => 'publication_date', 
   type => 'date', 
   render_res => 'month', 
   render_style => short',