Mongo DB Query

Ø  Find all collection names:  To find all collection names in mongo database use the below query.

db.getCollectionNames()

Return Type:  Array

Ø  Find all documents from collection name: To find document from collection name use the below query.

db.<<collectionName>>.find()

Return Type:  Cursor (i.e. collection of objects)

Ø  Find document(s) based on filter criteria: To find document based on filter criteria use the below query.

db.<<collectionName>>.find({ <field1>: <value1>, <field2>: <value2>, ... })

For the nested field use the dot(.) operator with value to find the document.

Return Type:  Cursor (i.e. collection of objects)

Ø  Find document(s)  using operators: To create condition with operator use the below syntax:

db.<<collectionName>>.find({  <field1>: { <operator1>: <value1> }  })

Operators are: $lt, $gt,

For AND Operator:  Use comma (,) 

And

For OR Operator:  Use $OR

 db.<<collectionName>>.find( {  $or:  [  { field1: value1 }, { field2: value2 }  ]  } )

Return Type:  Cursor (i.e. collection of objects)

Ø  Sort document in collection: To sort document in collection use the below query.

db.<<collectionName>>.find().sort({ “field1” : 1, “field2”: -1})

1 is used for Ascending and -1 is used for Descending.

Return Type:  Cursor (i.e. collection of objects)

Note: “Field Name” is case sensitive

Ø  Remove document from collection: To remove document from collection use the below query.

db.<<collectionName>>.remove({“fieldname”:”value”})