textdb

Simple text based db for node.js

Project goals are:

• in memory database, for nodejs
• can persist data (read/write) in a simple text based format
• support for relational data
• completely in javascript (actually, typescript)
• support for localstorage and use in browser (someday)

My usecase is for small (local) node applications. I want to be able to edit/read my personal data in plain text, and not having the hassle to setup a real database.

Also, if/when localStorage and browser is supported, this project may have an interest for some so-called isomorphic applications.

Status

This is a work VERY much in progress. Please don't use this in production for anything important.

• not production ready AT ALL
• most likely not performant for many cases (still very naive implementation)
• all the DB data is loaded in memory.
• no persistence so far: it can only read from a folder, but not write to it yet
• basic implementation for update/delete operations. These operations are probably not safe (for example, no check is done to make sure the new data is valid)

Installation

With npm:

npm install textdb  --save

This package is written in typescript, and compiled for es2015. I personally use the following flags to run it:

• --harmony: to enable general harmony features
• --harmony-destructuring: destructuring objects
• --harmony_default_parameters: default arguments for function parameters

In a node project, to import the main TextDB class:

var TextDB = require('textdb').default

Still not totally sure on the best way to proceed, but the 'default' part is still necessary. Someday, I will test and improve the build process.

Short User Guide

To instantiate a new empty (in memory) DB:

var TextDB = require('textdb).default

var db = new TextDB()

To add a table to the DB:

  db.createTable('accounts', {
    id: {type: 'word'},
    initialBalance: {type: 'amount'},
    description: {type: 'string'}
  })

To insert a record:

  db.insert('accounts', {id: 'current', initialBalance: 1000, description: 'main account'})
  db.insert('accounts', {id: 'savings', initialBalance: 50000, description: 'savings account'})

To query the db:

    const account = db.query('accounts', {where: c => c.initialBalance > 2000})

To update a record:

    db.update('accounts', 'current', {initialBalance: 42})

To delete a record:

    db.delete('accounts', 'current')

Note that deleting a record will fail if the record is reachable by a 'many2one' field.

Reading from a folder

A db can be created with a valid path

var db = new TextDB({path: '/path/to/my/data/folder'})

This will read all files from the folder, create the corresponding tables, and insert the records. See the test/ folder for an example.

A valid textdb folder is a folder with:

• a __schema__.json file, which contains a description of all the tables in the database
• a file for each of those tables, with one record per line

Fields

Basic fields

Here are the various type of fields currently supported:

• string
• integer
• word
• selection
• date
• amount

Relational fields

In addition to those fields, textdb currently supports:

• many2one

Support for one2many will be added at some point.