Express 文件（資料庫整合）

博弈發表於2019-02-16
Express資料庫

資料庫整合

新增將資料庫連線到Express應用程式的功能只需在應用程式中為資料庫載入適當的Node.js驅動程式，本文件簡要介紹瞭如何在Express應用程式中為資料庫系統新增和使用一些最流行的Node.js模組。

這些資料庫驅動程式是眾多可用的驅動程式，對於其他選項，請在npm網站上搜尋。

Cassandra

模組：cassandra-driver

安裝

$ npm install cassandra-driver

示例

var cassandra = require(`cassandra-driver`)
var client = new cassandra.Client({ contactPoints: [`localhost`] })

client.execute(`select key from system.local`, function (err, result) {
  if (err) throw err
  console.log(result.rows[0])
})

Couchbase

模組：couchnode

安裝

$ npm install couchbase

示例

var couchbase = require(`couchbase`)
var bucket = (new couchbase.Cluster(`http://localhost:8091`)).openBucket(`bucketName`)

// add a document to a bucket
bucket.insert(`document-key`, { name: `Matt`, shoeSize: 13 }, function (err, result) {
  if (err) {
    console.log(err)
  } else {
    console.log(result)
  }
})

// get all documents with shoe size 13
var n1ql = `SELECT d.* FROM `bucketName` d WHERE shoeSize = $1`
var query = N1qlQuery.fromString(n1ql)
bucket.query(query, [13], function (err, result) {
  if (err) {
    console.log(err)
  } else {
    console.log(result)
  }
})

CouchDB

模組：nano

安裝

$ npm install nano

示例

var nano = require(`nano`)(`http://localhost:5984`)
nano.db.create(`books`)
var books = nano.db.use(`books`)

// Insert a book document in the books database
books.insert({ name: `The Art of war` }, null, function (err, body) {
  if (err) {
    console.log(err)
  } else {
    console.log(body)
  }
})

// Get a list of all books
books.list(function (err, body) {
  if (err) {
    console.log(err)
  } else {
    console.log(body.rows)
  }
})

LevelDB

模組：levelup

安裝

$ npm install level levelup leveldown

示例

var levelup = require(`levelup`)
var db = levelup(`./mydb`)

db.put(`name`, `LevelUP`, function (err) {
  if (err) return console.log(`Ooops!`, err)

  db.get(`name`, function (err, value) {
    if (err) return console.log(`Ooops!`, err)

    console.log(`name=` + value)
  })
})

MySQL

模組：mysql

安裝

$ npm install mysql

示例

var mysql = require(`mysql`)
var connection = mysql.createConnection({
  host     : `localhost`,
  user     : `dbuser`,
  password : `s3kreee7`,
  database : `my_db`
});

connection.connect()

connection.query(`SELECT 1 + 1 AS solution`, function (err, rows, fields) {
  if (err) throw err

  console.log(`The solution is: `, rows[0].solution)
})

connection.end()

MongoDB

模組：mongodb

安裝

$ npm install mongodb

示例（v2.*）

var MongoClient = require(`mongodb`).MongoClient

MongoClient.connect(`mongodb://localhost:27017/animals`, function (err, db) {
  if (err) throw err

  db.collection(`mammals`).find().toArray(function (err, result) {
    if (err) throw err

    console.log(result)
  })
})

示例（v3.*）

var MongoClient = require(`mongodb`).MongoClient

MongoClient.connect(`mongodb://localhost:27017/animals`, function (err, client) {
  if (err) throw err

  var db = client.db(`animals`)
  
  db.collection(`mammals`).find().toArray(function (err, result) {
    if (err) throw err

    console.log(result)
  })
})

如果你想要MongoDB的物件模型驅動程式，請檢視Mongoose。

Neo4j

模組：apoc

安裝

$ npm install apoc

示例

var apoc = require(`apoc`)

apoc.query(`match (n) return n`).exec().then(
  function (response) {
    console.log(response)
  },
  function (fail) {
    console.log(fail)
  }
)

Oracle

模組：oracledb

安裝

注意：請參閱安裝前提條件。

$ npm install oracledb

示例

const oracledb = require(`oracledb`);
const config = {
  user: `<your db user>`,                // Update me
  password: `<your db password>`,        // Update me
  connectString: `localhost:1521/orcl`   // Update me
};

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);

PostgreSQL

模組：pg-promise

安裝

$ npm install pg-promise

示例

var pgp = require(`pg-promise`)(/*options*/)
var db = pgp(`postgres://username:password@host:port/database`)

db.one(`SELECT $1 AS value`, 123)
  .then(function (data) {
    console.log(`DATA:`, data.value)
  })
  .catch(function (error) {
    console.log(`ERROR:`, error)
  })

Redis

模組：redis

安裝

$ npm install redis

示例

var redis = require(`redis`)
var client = redis.createClient()

client.on(`error`, function (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`, function (err, replies) {
  console.log(replies.length + ` replies:`)

  replies.forEach(function (reply, i) {
    console.log(`    ` + i + `: ` + reply)
  })

  client.quit()
})

SQL Server

模組：tedious

安裝

$ npm install tedious

示例

var Connection = require(`tedious`).Connection;
var Request = require(`tedious`).Request;

var config = {
  userName: `your_username`, // update me
  password: `your_password`, // update me
  server: `localhost`
}

var connection = new Connection(config);

connection.on(`connect`, function(err) {
  if (err) {
    console.log(err);
  } else {
    executeStatement();
  }
});

function executeStatement() {
  request = new Request("select 123, `hello world`", function(err, rowCount) {
    if (err) {
      console.log(err);
    } else {
      console.log(rowCount + ` rows`);
    }
    connection.close();
  });

  request.on(`row`, function(columns) {
    columns.forEach(function(column) {
      if (column.value === null) {
        console.log(`NULL`);
      } else {
        console.log(column.value);
      }
    });
  });

  connection.execSql(request);
}

SQLite

模組：sqlite3

安裝

$ npm install sqlite3

示例

var sqlite3 = require(`sqlite3`).verbose()
var db = new sqlite3.Database(`:memory:`)

db.serialize(function () {
  db.run(`CREATE TABLE lorem (info TEXT)`)
  var stmt = db.prepare(`INSERT INTO lorem VALUES (?)`)

  for (var i = 0; i < 10; i++) {
    stmt.run(`Ipsum ` + i)
  }

  stmt.finalize()

  db.each(`SELECT rowid AS id, info FROM lorem`, function (err, row) {
    console.log(row.id + `: ` + row.info)
  })
})

db.close()

ElasticSearch

模組：elasticsearch

安裝

$ npm install elasticsearch

示例

var elasticsearch = require(`elasticsearch`)
var client = elasticsearch.Client({
  host: `localhost:9200`
})

client.search({
  index: `books`,
  type: `book`,
  body: {
    query: {
      multi_match: {
        query: `express js`,
        fields: [`title`, `description`]
      }
    }
  }
}).then(function (response) {
  var hits = response.hits.hits
}, function (error) {
  console.trace(error.message)
})

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