erldb

ORM (Object-relational mapping) application implemented in Erlang. Still in very much beta :-)

Configure erldb

Currently erldb supports two different backends; ets and mysql. We are hoping to support more.

Writing models

This section will be written soon

Basic structure

A model is defined by a basic set of attributes.

Relations

There is currently two different relations in erldb;

-relation(has, AMOUNT, MODEL_NAME). - Defines a one -> N relation. -relation(belongs_to, MODEL_NAME).

Trigger functions

Pre triggers

Pre-triggers can be defined by including the function _pre_TRIGGERNAME/1 where the triggername can be one of: update, lookup, delete or insert.

Post triggers

Post-triggers are defined almost the same as for pre-triggers. Just change pre to _post. Example: _post_update/1

Compile the models

Right now you have to compile the models yourself. Please take a look at the compilemodel-script located in the priv-directory of this repository.

Build

To build erldb use rebar3:

  $ rebar3 compile

Documentation

To generate documentation of erldb:

  $ rebar3 edocs

Try it out!!

Check the models/-directory for example models. To compile the model tags.erl;

  $ rebar3 shell

  ...compilation output...

  1> erldb_compiler:compile("examples/tags.erl", [{includedir, "./include"}, {outdir, "."}]).
  {ok,tags}

Now you can read the record definitions for each of the models within erlang:

  2> rr("include/tags.hrl").
  [tags]
  3> A = #tags{}.
  #tags{id = undefined,title = "Fancy title",text = undefined,
        created = undefined}
  4> B = A:uppercase_title().
  "FANCY TITLE"
  5> B:save()
  {ok,#tags{author_id = undefined,id = id,
          title = "FANCY TITLE",text = undefined,created = undefined}}
  6> erldb:find(tags, []).
  {ok,[#tags{author_id = undefined,id = id,
           title = "FANCY TITLE",text = undefined,
           created = undefined}]}