places.sqlite::moz_places

This table records each URL visited and the information associated with that particular URL.

Schema

CREATE TABLE moz_places (id INTEGER PRIMARY KEY, url LONGVARCHAR, title LONGVARCHAR, rev_host LONGVARCHAR, visit_count INTEGER DEFAULT 0, hidden INTEGER DEFAULT 0 NOT NULL, typed INTEGER DEFAULT 0 NOT NULL, favicon_id INTEGER, frecency INTEGER DEFAULT -1 NOT NULL)

id	One-to-many relationship with places.sqlite::moz_historyvisits::place_id
url	URL visited and the protocol used. For example: http://www.... file:///C:/Documents and Settings/... ftp://ftp.mozilla.org https://www.bank.co.uk
title	Text shown in the title bar of the web-browser. If URL is HTML then this will be taken from <title> tag if available.
rev_host	The host name of the URL visited reversed with a trailing period. A visit to the URL 'www.google.co.uk/news' would have a rev_host entry of 'ku.oc.elgoog.www.'. The reason for doing this is shown in the Firefox source code: This extracts the hostname from the URI and reverses it in the form that we use (always ending with a "."). So "http://microsoft.com/" becomes "moc.tfosorcim." The idea behind this is that we can create an index over the items in the reversed host name column, and then query for as much or as little of the host name as we feel like. For example, the query "host >= 'gro.allizom.' AND host < 'gro.allizom/'" Matches all host names ending in '.mozilla.org', including 'developer.mozilla.org' and just 'mozilla.org' (since we define all reversed host names to end in a period, even 'mozilla.org' matches). The important thing is that this operation uses the index. Any substring calls in a select statement (even if it's for the beginning of a string) will bypass any indices and will be slow). Source: [1]
visit_count	The number of times that this URL has been visited. This counter is incremented when the associated places.sqlite::moz_historyvisits::visit_type is not 0, 4 (embedded), or 7 (download). Research by the author shows that reloading a page by clicking the 'Reload current page' button, pressing CTRL-R or following a self-referring URL does not increment visit_count. If the start-up option to 'Show my windows and tabs from last time' is selected, the visit_count of those pages will NOT be incremented when the browser is started and they are loaded. If the start-up option to 'Show my home page' is selected, the visit_count of the home page WILL be incremented each time the browser is started and they are loaded. Sources: [1] [2]
hidden	0 = No 1 = Yes A hidden URL is one that the user did not specifically navigate to. These are commonly embedded pages, i-frames, RSS bookmarks and javascript calls. Source: [1]
typed	0 = No 1 = Yes A typed URL is one that the user typed directly into the location/URL bar. This can occur by either the user typing a complete URL and pressing enter, or by typing in a partial URL/keyword and then selecting a suggestion shown in the auto-complete drop-down bar. If the user types in a non-URL term for example 'FBI' into the location/URL bar, this would take the user to the URL 'http://www.fbi.gov/' through an automatic querying of google. This would NOT be recorded as a typed URL.
favicon_id	Many-to-one relationship with places.sqlite::moz_historyvisits::place_id
frecency	A combination of frequency and recency. Used to order suggestions in the auto-complete function of the location/URL bar. URLs visited more recently, more often, or by more direct means i.e. typing in the URL, will have a higher frecency value. The frecency of sites is calculated when the browser is idle. A frequency of -1 means that the frecency for that URL has not yet been calculated. If it is set to 0 will be excluded from the autocomplete bar. All others will be ordered based on their frecency. Sources: [1] [2] [3] [4] [5]