===== Db command tutorial =====

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]]

=====Auto completion=====

Like in every Linux shell you can use the TAB key when you use the command line to auto complete or propose all available answers

=====Usage=====
<WRAP center round tip 60%>
Use of 'config' is a shorthand version for 'db configuration' and therefore only works with the configuration database
</WRAP>
====Keys/Properties/values====

All turn around A key with properties and values of the properties, no more, no less. You can have a lot of properties under a key which is unique

  # db configuration show passwordstrength    <- database => configuration
   passwordstrength=configuration             <- Key (type = configuration) 
     Admin=strong                             <- property (value = strong)
     Ibays=strong                             <- property (value = strong)
     MaxPassAge=180                           <- property (value = 180)
     MinPassAge=0                             <- property (value = 0)
     PassExpires=yes                          <- property (value = yes)
     PassWarning=7                            <- property (value = 7)
     Users=strong                             <- property (value = strong)


Apply the above "reasoning" to any database and the the syntax presented by issuing db then makes sense.

Note that missing (or no) properties and values do not necessarily mean no value is in the /etc/file.conf system, as the template code can have a default value in the absence of a specific db value.

Note to determine what db settings are supported by sme code, or what the default values are, refer to (ie read) the code that is in the particular template or custom template associated with a /etc/file.conf
 
Look in /etc/e-smith/templates/... and /etc/e-smith/templates-custom/....
and subfolders and template fragments applicable to particular /etc/file.conf configuration files.


====show all available databases====
To show a list of existing databases do
  ls -al /var/lib/nethserver/db/

To show the keys for the two main databases do:
  db configuration show |less
That can be abbreviated to
  config show |less

  db accounts show |less

Note after using the |less switch, press Enter to scroll down a line at a time, or press Space to scroll down a page at a time. 'q' to quit.
====Create a  key in a database====
the generic command is :
  db dbfile set key type [prop1 val1] [prop2 val2] ...

  dbfile : choose the database in /var/lib/nethserver/db/
  key : the name of key
  type : generally 'service' or 'configuration' but it can be other things as webbapps or url or ...
 
If you want to create a keys called 'plop' in the configuration database with a type as 'configuration you can do like this

  db configuration set plop configuration Name wordpress PublicAccess private status enabled DbName wordpress DbUser wordpress WpLang en

you can see the result

  config show plop
or 
  db configuration show plop

  plop=configuration
    DbName=wordpress
    DbUser=wordpress
    Name=wordpress
    PublicAccess=private
    WpLang=en
    status=enabled

====Change values of properties====
The generic command line is 
  db dbfile setprop key prop1 val1 [prop2 val2] [prop3 val3] ...


  dbfile : choose the database in /var/lib/nethserver/db/
  key : the name of key

Then if you want to modify some values of our example above
  db configuration setprop plop PublicAccess public WpLang fr
or
  config setprop plop PublicAccess public WpLang fr

We want to verify
  config show plop 
or
  db configuration show plop

  plop=configuration
    DbName=wordpress
    DbUser=wordpress
    Name=wordpress
    PublicAccess=public  <----------Here
    WpLang=fr            <----------Here
    status=enabled

====Create a property under a key====

Same as above, really not difficult

  db configuration setprop plop PlopTheWorld YES             
or
  config setprop plop PlopTheWorld YES             

and to display modification

  db configuration show plop
or
  config show plop

  plop=configuration
    DbName=wordpress
    DbUser=wordpress
    Name=wordpress
    PlopTheWorld=YES    <----------Here
    PublicAccess=public
    WpLang=fr
    status=enabled

==== Setting db variables to default values ====
<WRAP center round tip 60%>
Use of 'config' is a shorthand version for 'db configuration' and therefore only works with the configuration database
</WRAP>


Any db variable that has a default value can be reset to the default by deleting the variable entirely, then re-initializing the default database values as follows:
 config delprop <key> <prop>
 /etc/e-smith/events/actions/initialize-default-databases

for example
  db configuration delprop plop WPlang
  /etc/e-smith/events/actions/initialize-default-databases
or
  config delprop plop WpLang
  /etc/e-smith/events/actions/initialize-default-databases

==== Delete a property value ====
To delete the property
  db dbfile delprop <key> <prop>
for example
  db configuration delprop plop WpLang
or
  config delprop plop WpLang

==== Delete a Key ====
To delete the Key
  db dbfile delete <key>
for example
  db configuration delete plop
or
  config delete plop

==== Reset a property to an empty value ====
To reset to an empty value
 db dbfile setprop <key> <prop> <nowiki>''</nowiki>

for example
  db configuration setprop plop WpLang ''
or
  config setprop plop WpLang ''

<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 mistake.
</WRAP>


{{tag> neth-howto }}