The ICU maintains two tables of players, one in the main (www) database and one in the ratings database. The main database contains every player who has ever been assigned an ICU ID. However the players in the ratings database are a subset of the total and do not, for example, include foreign players or domestic players who are no longer active. This avoids cluttering up player lists (as used, for example, by tournament controllers in their pairings programs) with irrelevant entries. The difference between the two tables is determined by player classification.
This is explained in detail below but, in case just you're looking for a short summary, here it is: to synchronise a player who is no longer inactive to the ratings database, get the webmaster to update their status to active in the main database.
There are three independent dimensions for classifying each player record: status, source and duplication.
A player's status is one of the following:
There are approximately 3400 players in the main database who have been identified as foreign. These records accumulated during the years when the ICU's ratings software was such that every player, even (for example) the opponents of Irish players competing abroad, had to have an ICU ID. Nowadays, when rating tournaments with foreign players, all that's needed is their name and FIDE rating, they no longer require an ICU ID.
This relates to which of the ICU's various computer systems the record was first created in (see article). A record has one of the following sources:
The archive database dates from sometime before 2000 and contained a mixture of players who had, at that time, been classified as inactive and various duplicates (certain and possible). The certain duplicates (which matched another record by both name and DOB) were discarded when the data was imported but the possible duplicates remain. By default, records from the archive have inactive status (unless they are resurrected - see below).
The main difference between imported records and records from the archive is the quality of data. Players from the old archive will contain a higher proportion of possible duplicates.
Every record has field used to indicate duplication. Usually this field is empty, but if it contains an ICU ID then it means the record is a confirmed duplicate of the indicated ID and should not be used. These duplicates stem from human errors made by subscribers, tournament reporters and rating officers accumulated over the history of the ICU's various computer systems (see article).
Many records are possible duplicates but not yet marked as such due to lack of corroborating evidence. A mere name match is not sufficient; something extra like a DOB match is required to confirm a duplicate.
The main database is the master. New players are created there (usually when someone pays their ICU membership subscription for the first time) and updates or corrections to existing players (by the webmaster) are performed on the main website. Once a day, early in the morning, the two tables are synchronised by transferring new or updated data from the main database to ratings.
Current policy is to transfer only active and deceased players. Duplicates, foreigners and inactive players are excluded. Note that while deceased players will, of course, no longer be active, they still may have historical records (games and ratings since 2000) while, by definition, players classified as inactive will not.
When someone who has been inactive for many years starts playing again, then they need to be resurrected.
If the record for a player exists in the main database but not the ratings database and that person starts playing in tournaments again, then their main database record needs to be updated by the webmaster (to change their status from inactive to active). From that point onwards, that record will then be part of the nightly synchronisation between the main database and the ratings database. That facilitates tracking their rating starting from whatever old rating they have recorded in the system.
Each season a handful of players require resurrecting in this way. Often they match records sourced from the old archive database (see above) where the quality of data is poor. If you're the webmaster: