===== Db variable configuration =====

NethServer comes with the most used parameters set as variables in its internal configuration databases. These variables are used to store values to be used in the final configuration files. Please, read the [[http://docs.nethserver.org/projects/nethserver-devel/en/latest/databases.html|Database howto]], the [[http://docs.nethserver.org/projects/nethserver-devel/en/latest/templates.html|template howto]] and the [[http://docs.nethserver.org/projects/nethserver-devel/en/latest/events.html#signalling-events|event howto]] to understand the template and database process.

These variables are useful to configure your system more easily, as you do not need to modify configuration files directly for most common cases. It also makes it possible to administer the server through its server-manager as the database variables are used to set and change configuration parameters.  After editing, the configuration files must be regenerated and affected services need to be restarted.

For example, suppose you need to increase "memory-limit" in php.

You would simply execute these commands at the server console:

  db configuration setprop php MemoryLimit 64
  signal-event nethserver-php-save

The first line changes the value for the memory limit of PHP, the second line regenerates the configuration file and restart apache. 
<WRAP center round alert 60%>
**The signal-event is a mandatory to apply the modification**
</WRAP>

<WRAP center round tip 60%>
Database parameters are case sensitive so take great care when typing at the server shell because no error messages are given should you make a typo.
</WRAP>


The database system is based on a flat file system, but you should never edit them directly. Instead you should use the db command. More details on using the database system can be found in the [[http://docs.nethserver.org/projects/nethserver-devel/en/latest/index.html|Developer Manual]]

for a db command tutorial, please see [[db_command_tutorial|here]]

====Concept of the signal-event command====
Due to the efforts of the developers, you can further simplify the commands using the signal-event process.

==== Overview of database variables ====
The next section describes the standard variables defined on Nethserver. Please update this list with new standard variables in future SME Server versions.

The tables below have three columns. The first is the variable, the second is the target variable (located in the final configuration file), and the third is the default value.

A lot of the variables can be set using the server-manager but some can not. For example the variable DomainMaster for samba is not important here, because this can be set through server-manager. On the other hand, the variable RecycleBin is important, because it is not accessible through the server-manager.

Configuration files may use database values from a single configuration key, or may use multiple keys. 

It is also possible that multiple configuration files use the same key. An example of this is the httpd-admin key. This key has a variable TCPPort which is used in multiple files.