CODEWITHSUNDEEP
mongodbnosql
coulix
coulix

Reputation: 3368

Mongo collection doc organisation and query

I have logbook documents with a list of logs embedded:

{ 
    type:'logbook',
    name:'my book',
    userRef:2,
    cdate: ....,
    logs: [
      { 
          color: 'red',
          weight: 200,
          cdate: ...,
          foo: 'bar'
      },
      { 
          color: 'blue',
          weight: 100,
          cdate: ...,
          foo: 'bar'
      },
      { 
          color: 'green',
          weight: 240,
          cdate: ...,
          foo: 'bar'
      }
    ]

I would like to show paginated ordered log entries for a given logbook.

Is it possible to extract those from such a structure with mongo ?

If not should I have a logEntries collection for logs instead ?

Thanks

Upvotes: 0

Views: 320

Answers (1)

Niels van der Rest
Niels van der Rest

Reputation: 32184

You can specify which parts of a document you want to retrieve by using field selection. To select part of an array field, you can use the $slice operator, for example:

// select the name and a range of log entries from the document
db.logbooks.find({ name: "my book" }, { name: 1, logs: { $slice: [10, 5] } })

Note that any sorting of the log entries besides insertion order has to be done client-side.

Upvotes: 1

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