Wednesday 27 August 2014

mongoDB: Lesson2 : Creating Collection & Dropping Collection.

Hey Guys,
The fun continued here with mongodb next topic, creating collections(tables in RDBMS) and inserting documents(rows in table in RDBMS).



#
 Task
Syntax with Example




1




Collection








2




Creating Collection



Method -1 :


By using createCollection method
Using db.createCollection(name,options) function


Syntax: db.createCollection(<name>,<options>)

In the above syntax <name> is the name of the collection & options are various other parameters like capped, size, max and etc.(Refer official documentation for this).

Example 1: Just creating a collection Name

> db;
test

> db.createCollection("myFirstCollection");
{ "ok" : 1 }

> show collections;
myFirstCollection
nettuts
system.indexes
>

Example 2: Creating collection with along with document.

> db.mySecondCollection.save({"firstName":"sadakar","lastName":"pochampall",ID:200});
WriteResult({ "nInserted" : 1 })

> db.mySecondCollection.save({"firstName":"dolly","lastName":"boray",ID:201});
WriteResult({ "nInserted" : 1 })

> db.mySecondCollection.find();
{ "_id" : ObjectId("53fdbdbe268aa77e481c4a6c"), "firstName" : "sadakar", "lastName" : "pochampall", "ID" : 200 }
{ "_id" : ObjectId("53fdbde4268aa77e481c4a6d"), "firstName" : "dolly", "lastName" : "boray", "ID" : 201 }
>









3






Method -2:


By using insert method:
  • Insert method can be used in two ways.
    • Create documents separately and insert them into collection.


Create documents separately and insert them into collection.
Example:
> i={"firstName":"sadakar","lastName":"pochampalli",id:100};
{ "firstName" : "sadakar", "lastName" : "pochampalli", "id" : 100 }

> j={"firstName":"dolly","lastName":"boray",id:101};
{ "firstName" : "dolly", "lastName" : "boray", "id" : 101 }

> db.myFirstCollection.insert(i);
WriteResult({ "nInserted" : 1 })

> db.myFirstCollection.insert(j);
WriteResult({ "nInserted" : 1 })

> show collections;
myFirstCollection
nettuts
system.indexes

> db.myFirstCollection.find();
{ "_id" : ObjectId("53fdbaad268aa77e481c4a6a"), "firstName" : "sadakar", "lastName" : "pochampalli", "id" : 100 }
{ "_id" : ObjectId("53fdbab2268aa77e481c4a6b"), "firstName" : "dolly", "lastName" : "boray", "id" : 101 }
>







References :


http://docs.mongodb.org/manual/tutorial/getting-started/
http://docs.mongodb.org/manual/reference/method/db.createCollection/
http://docs.mongodb.org/manual/reference/method/db.collection.insert/





4

Drop Collection
Syntax: db.<CollectionName>.drop();


Example:
> db.myFirstCollection.drop();
true
>


:-)

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