Json Database

built-in json database, using lowdb package

basic

features

• small data volume: 0 to 100MB (single database)
• json Database
• compatible with lodash syntax

data file location

before packaging: the root directory of the project

electron-egg/data/xxx.json

packaged: software cache Directory

# windows (example)
C:\Users\Administrator\AppData\Roaming\ee\data\xxx.json
# macOS (example)
Users/apple/Library/Application Support/ee/data/xxx.json
# Linux (example)
$XDG_CONFIG_HOME or ~/.config/ee/data/xxx.json

example

• connection data ``` ‘use strict’;

const Service = require(‘ee-core’).Service; // Database objects provided by the framework const Storage = require(‘ee-core’).Storage; const _ = require(‘lodash’);

/**

• data storage

• @class */ class StorageService extends Service {

  constructor (ctx) { super(ctx);

  // lowdb this.systemDB = Storage.JsonDB.connection(‘system’);

  // demo db let lowdbOptions = { driver: ‘lowdb’ } this.demoDB = Storage.JsonDB.connection(‘demo’, lowdbOptions);
  } }

module.exports = StorageService;

- add data

/*

• add Test data */ async addTestData(user) { const key = this.demoDBKey.test_data; if (!this.demoDB.db.has(key).value()) { this.demoDB.db.set(key, []).write(); }

  const data = this.demoDB.db .get(key) .push(user) .write();

  return data; } ```

• delete data ``` /*

• del Test data */ async delTestData(name = ‘’) { const key = this.demoDBKey.test_data; const data = this.demoDB.db .get(key) .remove({name: name}) .write();

  return data; } ```

• modify data ``` /*

• modify Test data */ async updateTestData(name= ‘’, age = 0) { const key = this.demoDBKey.test_data; const data = this.demoDB.db .get(key) .find({name: name}) .assign({age: age}) .write();

  return data; } ```

• search for data ``` /*

• search Test data */ async getTestData(age = 0) { const key = this.demoDBKey.test_data; let data = this.demoDB.db .get(key) //.find({age: age}) .filter(function(o) {

  let isHas = true;
  isHas = age === o.age ? true : false;
  return isHas;

  }) //.orderBy([‘age’], [‘name’]) sort //.slice(0, 10) .value();

  if (_.isEmpty(data)) { data = [] }

  return data; }

/*

• all Test data */ async getAllTestData() { const key = this.demoDBKey.test_data; if (!this.demoDB.db.has(key).value()) { this.demoDB.db.set(key, []).write(); } let data = this.demoDB.db .get(key) .value();

  if (_.isEmpty(data)) { data = [] }

  return data; } ```

  More syntax

  Storage object documents

  https://www.yuque.com/u34495/mivcfg/vv5cmv

lodash documentation

https://www.lodashjs.com/