Using tags
==========

Tag is a special parameter which can be given for
a set of documents. The main purpose of tags is to
join a number of documents into one group and then 
while doing search to select a group of documents to
search through. 

You can use "Tag" command of indexer.conf to give some
tag value for a server or server subset. While doing
search you can specify tag value to search through
documents which tag matches given parameter with t=xxx
parameter, which can be passed from HTML form.
Take a look into indexer.conf-dist and search.htm-dist 
for explanation and examples.


Tags in SQL version
-------------------
Since version 3.1.x. tag type was changed from INT to CHAR.
CHAR type allows to use some nice features. Due to the fact
that since 3.1.x tag is tested against SQL LIKE operator, you 
can use '_' and '%' LIKE wildcards in tag parameter when doing
search. It makes possible that tag, like a category,  does 
support an idea of nesting. For example, documents with tag 
value "AB" can be found with both "A%" and "AB" tag limits.

Tags also give a way to make an URL a member of multiple
tag selections. Playing with LIKE wildcards you can easy
create two or more groups.

For example, tag "ABCDE" is the member of at least these 
selections:

_BCDE
A_CDE
AB_DE
ABC_E
ABCD_

Note that if you have big enough database and often use
tag limits, it is useful to create an index by field "tag"
in "url" table. This index is not created by default.


Tags in built-in database
-------------------------
Tags in built-in database do not support wildcards. So, only
those URLs which have the same tag value with given in t=xxx
query string part will be searched through.

