# File lock codes

Attributes 5 and 6 of file-defining items can contain retrieval
and update lock codes respectively. These codes are used to restrict
access to certain data files and master dictionaries. Lock codes are
sets of characters used as codes. Multiple lock codes are separated
by value marks. The first lock code (retrieval or update) in a master
dictionary or file dictionary must be matched in attribute 6 (key)
of the user’s item in the users file to allow access to the file or
master dictionary. If the lock code does not match, access is denied.

Note: The DM user is a super-user. As such, the DM user
will bypass all update and retrieval locks.

Locks can be
placed at any file pointer level, system, master dictionary, or dictionary.
The system pointer controls access to a master dictionary; the master
dictionary pointer controls a file dictionary, and a file dictionary
pointer controls the data file.

## Example(s)

In this example, a company has
four departments; finance, admin, mis, and ops. Each department is
maintained in a separate master dictionary. Users remain attached
to a specific master dictionary, but must be prevented from using
Q-pointers or path names to access files on any other master dictionary.

The locks as they display in the system-level D-pointers and the
user definitions in the mds file:

| ID: | finance.mstr | admin.mstr | mis.mstr | ops.mstr |
| --- | --- | --- | --- | --- |
| 001 | d | d | d | d |
| 002 | 67889 | 786554 | 45000 | 23007 |
| 003 | 11 | 27 | 13 | 11 |
| 004 | | | | |
| 005 | finance | admin | mis | ops |
| 006 | finance | admin | mis | ops |
| 007 | | | | |
| 008 | | | | |
| 009 | 1 | 1 | 1 | 1 |
| 010 | 10 | 10 | 10 | 10 |
A few of the users and their lock keys.

| user: | toms | glendaj | sama | carlak | gandalf |
| --- | --- | --- | --- | --- | --- |
| 006(keys) | admin | finance | mis | ops | admin]mis]ops |
Every user is restricted to those files found on the local
master dictionary except for gandalf. He can access files on 3 of
the four master dictionaries.

The next example illustrates setting
update and retrieval locks for two files on the admin account. The
files are called, payroll and reviews. A new category of supervisor
is added. The supervisor files are only accessible by users with this
key, regardless of the host master dictionary.

On the admin
account, these pointers define the dictionaries of the files:

| ID: | payroll | reviews |
| --- | --- | --- |
| 001 | d | d |
| 002 | 56678 | 344567 |
| 003 | 23 | 13 |
| 004 | | |
| 005 | supervisor | supervisor |
| 006 | supervisor | supervisor |
| 007 | | |
| 008 | | |
| 009 | 1 | 1 |
| 010 | 10 | 10 |
gandalf is now a supervisor:

| user: | gandalf |
| --- | --- |
| 006(keys) | admin]mis]ops]supervisor |
Now, gandalf can retrieve payroll and reviews but toms
is still restricted.

## See also

- [Retrieval and update locks](https://d3codex.com/definitions/retrieval-and-update-locks/)
- [retrieval-lock](https://d3codex.com/attributedefiningitem/retrieval-lock/)
- [Security](https://d3codex.com/definitions/security/)
- [update-lock](https://d3codex.com/attributedefiningitem/update-lock/)
- [users file](https://d3codex.com/systemfiles/users-file/)

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Source: https://d3codex.com/definitions/file-lock-codes/ - part of the D3Codex reference.