MongoDB Guide - csuohio.edu - Cleveland...

Sunnie Chung CIS 612

MongoDB Guide CIS 612 SS Chung

1. Installation

1) installing MongoDb

Sudo apt-get install mongoDb

after installing mongoDB, we have to make changes on it

Update apt-get update

2) Starting mogo services

MongoDB 2.4.9 (mongodb-osx-x86_64-2.4.9)

To start a MongoDB instance:

$ mongod mongod --help for help and startup options Tue Apr 1 15:19:17.445 [initandlisten] MongoDB starting : pid=616 port=27017


dbpath=/data/db/ 64-bit host=Thuats-MacBook-Pro.local Tue Apr 1 15:19:17.445 [initandlisten] Tue Apr 1 15:19:17.445 [initandlisten] ** WARNING: soft rlimits too low. Number of files is 256, should be at least 1000 Tue Apr 1 15:19:17.445 [initandlisten] db version v2.4.9 Tue Apr 1 15:19:17.445 [initandlisten] git version:

…

2. MongoDB Shell

MongoDB comes with a JavaScript shell that allows interaction with a MongoDB

instance from the command line.

To start the shell: $ mongo MongoDB shell version: 2.4.9 connecting to: test Welcome to the MongoDB shell. For interactive help, type "help". For more comprehensive documentation, see http://docs.mongodb.org/ Questions? Try the support group http://groups.google.com/group/mongodb-user Server has startup warnings: Tue Apr 1 15:19:17.445 [initandlisten] Tue Apr 1 15:19:17.445 [initandlisten] ** WARNING: soft rlimits too low. Number of files is 256, should be at least 1000 >

The shell is a full-featured JavaScript interpreter, capable of running JavaScript

programs.


3) get into mongo shell to check whether shell is running or not

4) From the mongo shell, confirm you are in the mydb database by issuing the

following:


5) If mongo does not return mydb for the previous operation, set the context to

the database, with the following operation:

6) Inserting into Database


• Creating a Documents j and k and insert into employee collection


• Finding particular data from the Collection

• Showing Collections in mydb

• Fetching distinct value

SQL Terms/Concepts MongoDB Terms/Concepts


SQL Terms/Concepts MongoDB Terms/Concepts

Database

Database

table Collection

row Document

column Field

index index

table joins embedded documents and linking

primary key

Specify any unique column or column combination as primary

key.

primary key

In MongoDB, the primary key is automatically set to

the_id field.

aggregation (e.g. group by) aggregation

SQL Terms, Functions, and Concepts MongoDB Aggregation Operators


SQL Terms, Functions, and Concepts MongoDB Aggregation Operators

WHERE $match

GROUP BY $group

HAVING $match

SELECT $project

ORDER BY $sort

LIMIT $limit

SUM() $sum

3. MongoDB Query/Syntax

The shell is standalone MongoDB client. On startup, the shell connects to the ‘test’

database and assigns this database connection to global variable ‘db’.

To show current databases > show dbs

local 0.078125GB

To create a new database: > use blog

If there is a database exists, then it switches to that one.

The CRUD operations used to manipulate and view data in the shell.


Create a new document: > post = {"title": "My Blog Post", "content" : "This is a blog post.", "data" : new Date()} { "title" : "My Blog Post", "content" : "This is a blog post.", "data" : ISODate("2014-04-01T19:39:36.521Z") }

‘post’ is a JavaScript object represents the documents, there are three keys ‘title’,

‘content’, and ‘date’

Insert into collection: > db.blog.insert(post)

To see the collection: > db.blog.find() { "_id" : ObjectId("533b16898bce20d2fd851cfc"), "title" : "My Blog Post", "content" : "This is a blog post.", "data" : ISODate("2014-04-01T19:39:36.521Z") }

> db.blog.findOne() { "_id" : ObjectId("533b16898bce20d2fd851cfc"), "title" : "My Blog Post", "content" : "This is a blog post.", "data" : ISODate("2014-04-01T19:39:36.521Z") }

To see how MongoDB created that document: > db.blog.find().explain() { "cursor" : "BasicCursor", "isMultiKey" : false, "n" : 1, "nscannedObjects" : 1, "nscanned" : 1, "nscannedObjectsAllPlans" : 1, "nscannedAllPlans" : 1, "scanAndOrder" : false, "indexOnly" : false, "nYields" : 0, "nChunkSkips" : 0, "millis" : 0, "indexBounds" : { }, "server" : "Thuats-MacBook-Pro.local:27017"

}

To update:


> post.comments = [] [ ] > db.blog.update({title: "My Blog Post"}, post) > db.blog.findOne() { "_id" : ObjectId("533b16898bce20d2fd851cfc"), "title" : "My Blog Post", "content" : "This is a blog post.", "data" : ISODate("2014-04-01T19:39:36.521Z"), "comments" : [ ] }

To delete: > db.blog.remove({title : "My Blog Post"}) > db.blog.findOne()

null

To build index: > db.blog.ensureIndex({title:1})

To show all existing indexes: > db.blog.getIndexes() [ { "v" : 1, "key" : { "_id" : 1 }, "ns" : "blog.blog", "name" : "_id_" }, { "v" : 1, "key" : { "title" : 1 }, "ns" : "blog.blog", "name" : "title_1" }

]

To remove index: > db.blog.dropIndex({title:1}) { "nIndexesWas" : 2, "ok" : 1 }


Insert with and without giving _Id


Store Function


Create Collection


Map and Reduce

4. MongoDB Application

MongoDB Drivers and Client Libraries: MongoDB supports variety of modern

programming languages including C, C++, C#, Java, Node.js, PHP, Python…

Example of MongoDB application with Java:


MongoDB-Java-Driver-2.12.0

try {

// connect to MongoDB server

MongoClient mongo = new MongoClient("localhost" , 27017);

// display all databases

List<String> dbs = mongo.getDatabaseNames();

System.out.println("Databases:");

for(String db : dbs) {

System.out.println(db);

}

System.out.println();

// display collections

DB db = mongo.getDB("blog");

Set<String> collections = db.getCollectionNames();

System.out.println("Collections:");

for (String string : collections) {

System.out.println(string);

}

System.out.println();

// save a document into collection

DBCollection collection = db.getCollection("blog");

BasicDBObject document = new BasicDBObject();

document.put("title", "My Blog Post 2");

document.put("content", "This is blog post 2.");

document.put("data", new Date());

collection.insert(document);

// update document

BasicDBObject oldObject = new BasicDBObject();

oldObject.put("title", "My Blog Post");

BasicDBObject newObject = new BasicDBObject();

newObject.put("title", "My Blog Post - updated");

BasicDBObject updateObject = new BasicDBObject();

updateObject.put("$set", newObject);

collection.update(oldObject, updateObject);

// find document

BasicDBObject searchObject = new BasicDBObject();

searchObject.put("title", "My Blog Post - updated");

DBCursor cursor = collection.find(searchObject);

while (cursor.hasNext()) {

System.out.println(cursor.next());

}

} catch (UnknownHostException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

Output: Databases:

blog

local


Collections:

blog

system.indexes

{ "_id" : { "$oid" : "5346493bcf16e43d6ecc279d"} , "content" :

"This is a blog post." , "data" : { "$date" : "2014-04-

10T07:26:12.828Z"} , "title" : "My Blog Post - updated"}

5. MongoDB Import/Export

MongoDB can import input files of formats JSON, CSV or TSV and also can export

database to those format using mongoimport and mongoexport respectively.

Syntax: mongoimport --collection collection --file collection.json mongoexport --collection collection --out collection.json

Import a CSV file (NASDAQ_daily_prices_B.csv) into MongoDB collection stocks

$ cat NASDAQ_daily_prices_B.csv exchange,stock_symbol,date,stock_price_open,stock_price_high,stock_price_low,stock_price_close,stock_volume,stock_price_adj_close NASDAQ,BBND,2010-02-08,2.92,2.98,2.86,2.96,483800,2.96 NASDAQ,BBND,2010-02-05,2.85,2.94,2.79,2.93,884000,2.93 NASDAQ,BBND,2010-02-04,2.83,2.88,2.78,2.83,1333300,2.83 NASDAQ,BBND,2010-02-03,2.98,3.03,2.80,2.83,1015800,2.83 NASDAQ,BBND,2010-02-02,3.05,3.10,2.96,2.97,513100,2.97 NASDAQ,BBND,2010-02-01,3.11,3.13,3.00,3.04,997000,3.04 NASDAQ,BBND,2010-01-29,3.01,3.14,2.96,3.14,1132900,3.14 … $ mongoimport --db stocks --collection nasdaq_daily_prices --type csv --file /Users/nqt289/Desktop/NASDAQ_daily_prices_B.csv --headerline connected to: 127.0.0.1 Thu Apr 10 05:24:46.009 Progress: 780677/21998523 3% Thu Apr 10 05:24:46.009 14000 4666/second Thu Apr 10 05:24:49.004 Progress: 2011431/21998523 9% Thu Apr 10 05:24:49.004 36200 6033/second Thu Apr 10 05:24:52.004 Progress: 3300955/21998523 15% Thu Apr 10 05:24:52.004 58600 6511/second Thu Apr 10 05:24:55.005 Progress: 4575925/21998523 20% Thu Apr 10 05:24:55.006 81300 6775/second Thu Apr 10 05:24:58.009 Progress: 5845580/21998523 26% Thu Apr 10 05:24:58.009 104000 6933/second Thu Apr 10 05:25:34.005 374000 7333/second …


Thu Apr 10 05:25:35.956 check 9 388777 Thu Apr 10 05:25:35.956 imported 388776 objects

Check result collection in the shell: > show dbs blog 0.203125GB local 0.078125GB stocks 0.453125GB > use stocks switched to db stocks > show tables nasdaq_daily_prices system.indexes > db.nasdaq_daily_prices.find().limit(5) { "_id" : ObjectId("5346635c6857e587111a2466"), "exchange" : "NASDAQ", "stock_symbol" : "BBND", "date" : "2010-02-08", "stock_price_open" : 2.92, "stock_price_high" : 2.98, "stock_price_low" : 2.86, "stock_price_close" : 2.96, "stock_volume" : 483800, "stock_price_adj_close" : 2.96 } { "_id" : ObjectId("5346635c6857e587111a2467"), "exchange" : "NASDAQ", "stock_symbol" : "BBND", "date" : "2010-02-05", "stock_price_open" : 2.85, "stock_price_high" : 2.94, "stock_price_low" : 2.79, "stock_price_close" : 2.93, "stock_volume" : 884000, "stock_price_adj_close" : 2.93 } { "_id" : ObjectId("5346635c6857e587111a2468"), "exchange" : "NASDAQ", "stock_symbol" : "BBND", "date" : "2010-02-04", "stock_price_open" : 2.83, "stock_price_high" : 2.88, "stock_price_low" : 2.78, "stock_price_close" : 2.83, "stock_volume" : 1333300, "stock_price_adj_close" : 2.83 } { "_id" : ObjectId("5346635c6857e587111a2469"), "exchange" : "NASDAQ", "stock_symbol" : "BBND", "date" : "2010-02-03", "stock_price_open" : 2.98, "stock_price_high" : 3.03, "stock_price_low" : 2.8, "stock_price_close" : 2.83, "stock_volume" : 1015800, "stock_price_adj_close" : 2.83 } { "_id" : ObjectId("5346635c6857e587111a246a"), "exchange" : "NASDAQ", "stock_symbol" : "BBND", "date" : "2010-02-02", "stock_price_open" : 3.05, "stock_price_high" : 3.1, "stock_price_low" : 2.96, "stock_price_close" : 2.97, "stock_volume" : 513100, "stock_price_adj_close" : 2.97 }

Export that collection to JSON format: $ mongoexport -d stocks -c nasdaq_daily_prices -q "{stock_price_open: { \$gte: 50 }}" --out /Users/nqt289/Desktop/gte50.json connected to: 127.0.0.1 exported 9911 records

$ cat gte50.json { "_id" : { "$oid" : "5346635d6857e587111a4cda" }, "exchange" : "NASDAQ", "stock_symbol" : "BOLT", "date" : "2007-07-25", "stock_price_open" : 51, "stock_price_high" : 51.47, "stock_price_low" : 44.1, "stock_price_close" : 47.04, "stock_volume" : 1109600, "stock_price_adj_close" : 31.36 }


{ "_id" : { "$oid" : "5346635d6857e587111a4cdb" }, "exchange" : "NASDAQ", "stock_symbol" : "BOLT", "date" : "2007-07-24", "stock_price_open" : 52.4, "stock_price_high" : 52.4, "stock_price_low" : 48.55, "stock_price_close" : 49.43, "stock_volume" : 650600, "stock_price_adj_close" : 32.95 } …

MongoDB Guide - csuohio.edu - Cleveland...

Documents

Transcript of MongoDB Guide - csuohio.edu - Cleveland...