MongoDB Database Commands with Examples

Question: Expalin the Basic terminology for MongoDB?

RDBMS	MongoDB
Database	Database
Table	Collection
Tuple/Row	Document
column	Field
Table Join	Embedded Documents
Primary Key	Primary Key (Default key _id provided by mongodb itself)
Mysqld/Oracle	mongod
mysql/sqlplus	mongo

Note: # used for commenting.

Question: Create a New database?

use mydb #switched to db mydb

Question: Check which database you are currently using?

use

Question: Display the List of databases?

show dbs #All database will display which have atleast 1 document.

Question: Delete the current database?

db.dropDatabase() #Delete the current used database.

Question: How to create collection for a database?

db.createCollection("mycollection") #create a collection for current selected database.

Question: Display the List of collections in database?

show collections #All collection will display for current database.

Question: How to drop the collection?

db.mycollection.drop() #mycollection collection will be deleted.

Question: How to delete all the records from mongodb ?

db.collection.remove();

Question: How to delete all the records with condition?

db.collection.remove({uid=111});

Will delete all the record where uid=1111

Question: How to insert data(Know as document) into collection?

db.mycollection.insert({
   _id: ObjectId(7df78ad89765),
   title: 'MongoDB Overview',    
   by: 'Web technology',   
   tags: ['mongodb', 'database', 'NoSQL'],   
})
#Single document is added in collection "mycollection" .

Question: How to add multiple document into collection in single command?

db.mycollection.insert({
   {   
   title: 'MongoDB Overview',    
   by: 'Web technology',   
   tags: ['mongodb', 'database', 'NoSQL'],   
   },
 
   {
   title: 'MongoDB Overview2',    
   by: 'Web technology experts notes',   
   tags: ['mongodb', 'database', 'NoSQL' ,'Multiple Record'],   
       
   }
])

Question: What is command for search a document? Give Example?
find() is used to search. For Example

db.mycollection.find()#Search the one document in un structured way .

Question: How to search a document in pretty way (structured way) ? Give Example?
pretty() is used to search in pretty way. For Example

db.mycollection.find({"by":"Web technology"}).pretty()#Search the one document in structured way .

Question: How to search a document with "and condition"?

db.mycollection.find({"by":"Web technology",{"title": "MongoDB Overview"}}).pretty()#Search the one document in structured way .

Question: How to list first 10 document?

db.mycollection.find({"by":"Web technology",{"title": "MongoDB Overview"}}).limit(10).pretty()#Search the 10 document in structured way .

Question: How to get 2nd document?

db.mycollection.find({"by":"Web technology",{"title": "MongoDB Overview"}}).limit(1).skip(1).pretty()#Search the 10 document in structured way .

Question: How to list document with title ascending order?

db.mycollection.find({"by":"Web technology",{"title": "MongoDB Overview"}}).sort({"title":1}).pretty()#Search the in title ascending order.

Question: How to search document in title descending order?

db.mycollection.find({"by":"Web technology",{"title": "MongoDB Overview"}}).sort({"title":-1}).pretty()#Search the in title descending order.

Question: How to Add indexing?

db.mycollection.ensureIndex({"title":1,"description":-1})#title in ascending order and description in descending order.To create index in descending order you need to use -1.

Question: How to search a document with "OR condition"?

db.mycollection.find({"by":"Web technology",$or[{"title": "MongoDB Overview"}]}).pretty()#Search the one document in structured way .

Question: How to update a document?

db.mycollection.update({'title':'MongoDB Overview'},{$set:{'title':'MongoDB text'}})#update "MongoDB Overview" with "MongoDB text " .

Question: How to delete a document?

db.mycollection.remove({'title':'MongoDB Overview'})#Delete the record where document is 'MongoDB Overview' .

Find all records

db.mycollection.find();

Display all the records in this collection.

Find all records and display in pretty way

db.mycollection.find().pretty();

Display all the records in this collection but presentable way.

Find all records with single condition (Age: 29)

db.mycollection.find({age:29});

Display all the records where age=29.

Find all records with multiple AND condition (Age: 29, Number:17)

db.mycollection.find({age:29, number:17});

Display all the records where age=29 and number=17

Find all records with multiple OR condition (Age: 29 OR Number:17)

db.mycollection.find({$or:[{age:29},{number:17}]});

Display all the records where age=29 OR number=17 (each of one).

Find all records with multiple OR condition (Age>28 OR Number:17)

db.mycollection.find({$or:[{age:{$gt:28}},{number:17}]});

Display all the records where age>29 and number=17

Find all records and display and one display column (name)

db.mycollection.find({},{name:1}).pretty();

Display all the name in this collections.

Find all records and display and two display column (name and number)

db.mycollection.find({},{name:1,number:1}).pretty();

Display all the name and number in this collections.

Limit the number of record

db.mycollection.find().limit(3).pretty();

Display only 3 records.

Display all the records except 1,2,3

db.mycollection.find().skip(3).pretty();

Skip first 3 records.

Web Technology Experts Notes

Monday, 30 November 2015