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General Discussion

Posted by Kevin Perez
Kevin Perez
Courses Plus Student 8,180 Points

Why do I have two records with the same Author Id?

db.posts.find({},{"_id":false,author:true})

{ "author" : ObjectId("5737abb574547531183e957c") }

{ "author" : ObjectId("5737abb574547531183e957d") }

{ "author" : ObjectId("5737abb574547531183e957e") }

{ "author" : ObjectId("5737abb574547531183e957c") }

db.posts.update({author:ObjectId("5737abb574547531183e957c")},{$set:{tags ['foo','bar'],title:"title update"}})

WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })

db.posts.find({author:ObjectId("5737abb574547531183e957c")},{title:true})

{ "_id" : ObjectId("5737abb574547531183e9581"), "title" : "title update" }

{ "_id" : ObjectId("5737abb574547531183e9584"), "title" : "Parenting 101" }

db.posts.find({},{title:true,author:true,_id:false})

{ "title" : "title update", "author" : ObjectId("5737abb574547531183e957c") }

{ "title" : "I love the holidays", "author" : ObjectId("5737abb574547531183e957d") }

{ "title" : "How to workout", "author" : ObjectId("5737abb574547531183e957e") }

{ "title" : "Parenting 101", "author" : ObjectId("5737abb574547531183e957c") }

1 Answer

anil rahman
anil rahman
7,786 Points
anil rahman
anil rahman
7,786 Points

I'm guessing in the table it looks kinda like this structure:

title                    authorID
--------                -----------
Parenting 101     1
parenting 201    1

If thats the case then the reason there is two rows with same author ID is because the author has two titles and each unique title has it's own row, so to denote that both titles are from that specific author you give the title the author/id.