====== Auxiliary fields ======

In the [[:components:search index]] the data about a document is stored in separate fields. This way you can decide which fields you want to be regarded when searching.

Using **auxiliary fields** you're able to define more fields besides the [[:components:search index#standard_fields|standard fields]]. This helps you to search more precisely.

===== How can I use this feature? =====

==== Example 1: Generate an auxiliary field from the URL ====

Assumed you have a network drive with a projects folder, which contains a sub folder for each project.

  c:
  +-- projects
      +-- gullivers
      +-- regain
      +-- marvin
      +-- blubb
      +-- ...

In this case you may for example add an auxiliary field ''project'', which contains for each document the name of the project the document belongs to. A search for "manual project:regain" would the search for the keyword "manual" in all documents in the project folder ''regain''.

For this auxiliary field you even may add a list box to the advanced search. This way you're able to select directly a certain project to search in.

To realize that example, you have to add the following entry to the [[:config:CrawlerConfiguration.xml#.3CauxiliaryFieldList.3E_tag|''auxiliaryFieldList'' tag]] in the [[:config:CrawlerConfiguration.xml]]:
<code xml>
<auxiliaryFieldList>
  <auxiliaryField name="project" regexGroup="1">
    <regex>^file://c:/projects/([^/]*)</regex>
  </auxiliaryField>
</auxiliaryFieldList>
</code>

The [[:config:regular expression]] defines, which documents are provided with the auxiliary field. The attribute ''regexGroup'' causes that the value of the auxiliary field is extracted from the first regex group: ''([^/]*)''.

With the URL ''<nowiki>file://c:/projects/marvin/docs/manual.pdf</nowiki>'' the auxiliary field ''project'' gets the value ''marvin''.

The URL ''<nowiki>file://c:/docs/letter.doc</nowiki>'' does not match the regular expression and therefore gets no auxiliary field ''project''.

==== Example 2: Sub collection ====

Instead of extracting the value of the auxiliary field from the URL, you may also specify a fixed value.

Assumed you have stored certain document types in certain folders on a network drive. E.g. your letters are stored in three different places. Using auxiliary fields you may limit a search on one document type. For example you may only search in your letters.

The according entry in the [[:config:CrawlerConfiguration.xml]] may look like this:
<code xml>
<auxiliaryFieldList>
  <auxiliaryField name="doctype" value="letter">
    <regex>^file://c:/projects/letters</regex>
  </auxiliaryField>

  <auxiliaryField name="doctype" value="letter">
    <regex>^file://e:/office/customer/(letters|correspondence)</regex>
  </auxiliaryField>

  <auxiliaryField name="doctype" value="offer">
    <regex>^file://e:/office/customer/offers/</regex>
  </auxiliaryField>

  <auxiliaryField name="doctype" value="specs">
    <regex>/spec(ification)?/</regex>
  </auxiliaryField>
</auxiliaryFieldList>
</code>

With the first two entries all documents in ''c:/projects/letters'', ''e:/office/customer/letters'' and ''e:/office/customer/correspondence'' get an auxiliary field ''doctype'' with the value ''letter''.

The third entry causes that all documents in ''e:/office/customer/offers'' get an auxiliary field ''doctype'' with the value ''offer''.

With the last entry all documents having ''anywhere'' in their URL a ''/spec/'' or a ''/specification/'' get an auxiliary field ''doctype'' with the value ''specs''.

All other document get no auxiliary field ''doctype''.