データベースの統合

$ npm install cassandra-driver

const cassandra = require('cassandra-driver')
const client = new cassandra.Client({ contactPoints: ['localhost'] })
client.execute('select key from system.local', (err, result) => {
 if (err) throw err
 console.log(result.rows[0])
})

$ npm install couchbase

const couchbase = require('couchbase')
const bucket = (new couchbase.Cluster('http://localhost:8091')).openBucket('bucketName')
// add a document to a bucket
bucket.insert('document-key', { name: 'Matt', shoeSize: 13 }, (err, result) => {
 if (err) {
 console.log(err)
 } else {
 console.log(result)
 }
})
// get all documents with shoe size 13
const n1ql = 'SELECT d.* FROM `bucketName` d WHERE shoeSize = 1ドル'
const query = N1qlQuery.fromString(n1ql)
bucket.query(query, [13], (err, result) => {
 if (err) {
 console.log(err)
 } else {
 console.log(result)
 }
})

$ npm install nano

const nano = require('nano')('http://localhost:5984')
nano.db.create('books')
const books = nano.db.use('books')
// Insert a book document in the books database
books.insert({ name: 'The Art of war' }, null, (err, body) => {
 if (err) {
 console.log(err)
 } else {
 console.log(body)
 }
})
// Get a list of all books
books.list((err, body) => {
 if (err) {
 console.log(err)
 } else {
 console.log(body.rows)
 }
})

$ npm install level levelup leveldown

const levelup = require('levelup')
const db = levelup('./mydb')
db.put('name', 'LevelUP', (err) => {
 if (err) return console.log('Ooops!', err)
 db.get('name', (err, value) => {
 if (err) return console.log('Ooops!', err)
 console.log(`name=${value}`)
 })
})

$ npm install mysql

const mysql = require('mysql')
const connection = mysql.createConnection({
 host: 'localhost',
 user: 'dbuser',
 password: 's3kreee7',
 database: 'my_db'
})
connection.connect()
connection.query('SELECT 1 + 1 AS solution', (err, rows, fields) => {
 if (err) throw err
 console.log('The solution is: ', rows[0].solution)
})
connection.end()

$ npm install mongodb

const MongoClient = require('mongodb').MongoClient
MongoClient.connect('mongodb://localhost:27017/animals', (err, db) => {
 if (err) throw err
 db.collection('mammals').find().toArray((err, result) => {
 if (err) throw err
 console.log(result)
 })
})

const MongoClient = require('mongodb').MongoClient
MongoClient.connect('mongodb://localhost:27017/animals', (err, client) => {
 if (err) throw err
 const db = client.db('animals')
 db.collection('mammals').find().toArray((err, result) => {
 if (err) throw err
 console.log(result)
 })
})

$ npm install neo4j-driver

const neo4j = require('neo4j-driver')
const driver = neo4j.driver('neo4j://localhost:7687', neo4j.auth.basic('neo4j', 'letmein'))
const session = driver.session()
session.readTransaction((tx) => {
 return tx.run('MATCH (n) RETURN count(n) AS count')
 .then((res) => {
 console.log(res.records[0].get('count'))
 })
 .catch((error) => {
 console.log(error)
 })
})

$ npm install oracledb

const oracledb = require('oracledb')
const config = {
 user: '<your db user>',
 password: '<your db password>',
 connectString: 'localhost:1521/orcl'
}
async function getEmployee (empId) {
 let conn
 try {
 conn = await oracledb.getConnection(config)
 const result = await conn.execute(
 'select * from employees where employee_id = :id',
 [empId]
 )
 console.log(result.rows[0])
 } catch (err) {
 console.log('Ouch!', err)
 } finally {
 if (conn) { // conn assignment worked, need to close
 await conn.close()
 }
 }
}
getEmployee(101)

$ npm install pg-promise

const pgp = require('pg-promise')(/* options */)
const db = pgp('postgres://username:password@host:port/database')
db.one('SELECT 1ドル AS value', 123)
 .then((data) => {
 console.log('DATA:', data.value)
 })
 .catch((error) => {
 console.log('ERROR:', error)
 })

$ npm install redis

const redis = require('redis')
const client = redis.createClient()
client.on('error', (err) => {
 console.log(`Error ${err}`)
})
client.set('string key', 'string val', redis.print)
client.hset('hash key', 'hashtest 1', 'some value', redis.print)
client.hset(['hash key', 'hashtest 2', 'some other value'], redis.print)
client.hkeys('hash key', (err, replies) => {
 console.log(`${replies.length} replies:`)
 replies.forEach((reply, i) => {
 console.log(` ${i}: ${reply}`)
 })
 client.quit()
})

$ npm install tedious

const Connection = require('tedious').Connection
const Request = require('tedious').Request
const config = {
 server: 'localhost',
 authentication: {
 type: 'default',
 options: {
 userName: 'your_username', // update me
 password: 'your_password' // update me
 }
 }
}
const connection = new Connection(config)
connection.on('connect', (err) => {
 if (err) {
 console.log(err)
 } else {
 executeStatement()
 }
})
function executeStatement () {
 request = new Request("select 123, 'hello world'", (err, rowCount) => {
 if (err) {
 console.log(err)
 } else {
 console.log(`${rowCount} rows`)
 }
 connection.close()
 })
 request.on('row', (columns) => {
 columns.forEach((column) => {
 if (column.value === null) {
 console.log('NULL')
 } else {
 console.log(column.value)
 }
 })
 })
 connection.execSql(request)
}

$ npm install sqlite3

const sqlite3 = require('sqlite3').verbose()
const db = new sqlite3.Database(':memory:')
db.serialize(() => {
 db.run('CREATE TABLE lorem (info TEXT)')
 const stmt = db.prepare('INSERT INTO lorem VALUES (?)')
 for (let i = 0; i < 10; i++) {
 stmt.run(`Ipsum ${i}`)
 }
 stmt.finalize()
 db.each('SELECT rowid AS id, info FROM lorem', (err, row) => {
 console.log(`${row.id}: ${row.info}`)
 })
})
db.close()

$ npm install elasticsearch

const elasticsearch = require('elasticsearch')
const client = elasticsearch.Client({
 host: 'localhost:9200'
})
client.search({
 index: 'books',
 type: 'book',
 body: {
 query: {
 multi_match: {
 query: 'express js',
 fields: ['title', 'description']
 }
 }
 }
}).then((response) => {
 const hits = response.hits.hits
}, (error) => {
 console.trace(error.message)
})