![findOne()
Find the first record in the document
> db.user.findOne()
{
"_id" : ObjectId("513c6ef1cfce9090d3fd8b1d"),
"date" : ISODate("2013-03-10T11:30:50.555Z"),
"remarks" : [
{
"name" : "anish",
"rate" : "good"
},
{
"name" : "nath",
"rate" : "bad"
}
],
"uName" : "anish"
}](https://image.slidesharecdn.com/mongodbreadingdocumentusecases-130502145348-phpapp02/85/Mongo-db-readingdocumentusecases-3-320.jpg)
![findOne() : specify which key to return
• Find the first record in the document and return only “_id”
> db.user.findOne({},{"_id":1})
{ "_id" : ObjectId("513c6ef1cfce9090d3fd8b1d") }
• Find the first record in the document and return only
“_id” and date
> db.user.findOne({},{"_id":1,"date":1})
{
"_id" : ObjectId("513c6ef1cfce9090d3fd8b1d"),
"date" : ISODate("2013-03-10T11:30:50.555Z")
}
• Find the first record in the document and return all the
data except the “_id” field
> db.user.findOne({},{"_id":0})
{
"date" : ISODate("2013-03-10T11:30:50.555Z"),
"remarks" : [
{
"name" : "anish",
"rate" : "good"
},
{
"name" : "nath",
"rate" : "bad"
}
],
"uName" : "anish"
}](https://image.slidesharecdn.com/mongodbreadingdocumentusecases-130502145348-phpapp02/85/Mongo-db-readingdocumentusecases-4-320.jpg)
![finding in Subdocument
>db.user.find(
{"remarks.name":"anish" })
{ "_id" :
ObjectId("513c6ef1cfce9090d3fd8b1d"),
"date" : ISODate("2013-03-
10T11:30:50.555Z"), "remarks" : [ {
"name
" : "anish", "rate" : "good" }, {
"name" : "nath", "rate" : "bad" } ],
"uName" : "anish" }](https://image.slidesharecdn.com/mongodbreadingdocumentusecases-130502145348-phpapp02/85/Mongo-db-readingdocumentusecases-5-320.jpg)
Mongo db readingdocumentusecases
- 1. MongoDB Reading/finding Document Reading/finding Document Use Case detailed
- 2. Reading/finding in Document Syntax db.collection.find( <query>, <projection> ) <query> argument corresponds to the WHERE statement, and <projection> argument corresponds to the list of fields to select from the result set.
- 3. findOne() Find the first record in the document > db.user.findOne() { "_id" : ObjectId("513c6ef1cfce9090d3fd8b1d"), "date" : ISODate("2013-03-10T11:30:50.555Z"), "remarks" : [ { "name" : "anish", "rate" : "good" }, { "name" : "nath", "rate" : "bad" } ], "uName" : "anish" }
- 4. findOne() : specify which key to return • Find the first record in the document and return only “_id” > db.user.findOne({},{"_id":1}) { "_id" : ObjectId("513c6ef1cfce9090d3fd8b1d") } • Find the first record in the document and return only “_id” and date > db.user.findOne({},{"_id":1,"date":1}) { "_id" : ObjectId("513c6ef1cfce9090d3fd8b1d"), "date" : ISODate("2013-03-10T11:30:50.555Z") } • Find the first record in the document and return all the data except the “_id” field > db.user.findOne({},{"_id":0}) { "date" : ISODate("2013-03-10T11:30:50.555Z"), "remarks" : [ { "name" : "anish", "rate" : "good" }, { "name" : "nath", "rate" : "bad" } ], "uName" : "anish" }
- 5. finding in Subdocument >db.user.find( {"remarks.name":"anish" }) { "_id" : ObjectId("513c6ef1cfce9090d3fd8b1d"), "date" : ISODate("2013-03- 10T11:30:50.555Z"), "remarks" : [ { "name " : "anish", "rate" : "good" }, { "name" : "nath", "rate" : "bad" } ], "uName" : "anish" }
- 6. findOne()/find() • Summary on <K,boolean> specify <“k”,0> or <“K”,1> to show/hide data to be returned from the collection