Database plugin: Provide migration support

[ohinckel]

To migrate from sqlite plugin to the database plugin we need to have

• a migration script which converts the items conf/yaml files
• a documentation how to migrate

(leftover from #165)

[psilo909]

will we really need a migration script for the CONF / YAML Files? wont an "extended replace" function of a good editor like notepad++ fit to the requirement?

[psilo909]

what we should do is a wiki page for the lesser technical people in here, e.g. how to install maria db, how to set a dedicated smarthome user, etc. i can start with that the next days.

[ohinckel]

Sure, one can just do a search replace magic. But I remember somebody asking for a migration script (like the conf to yaml converter). I'm think a migration is an easy step in the configuration file, too.

But what about the existing data in the databases. Do we need a script for dumping the old SQLite database and importing it into a new RDBMS database?

[psilo909]

@ohinckel didnt the "someone" mean a migration from sqlite .db file to e.g. maria db database?

[bmxp]

We actually alread have a "migration script" from conf to yaml since @msinn put it into tools/conf_to_yaml_converter.py. One just has to know about and use it. So we really just need a migration manual like the Komplettanleitung.

[psilo909]

@bmxp u get it wrong, @ohinckel means that we need a script like that to convert e.g. sqlite = yes to database = xyz

[ohinckel]

Added a simple script which converts conf/yaml files using sqlite settings to database settings. Because only the sqlite setting needs to be converted (also the possible values yes and init are supported by the database backend) it can be done be using a simple regex magic.