Which of the following statements are true about the _id field in MongoDB? (Select all that apply.) A. The user must specify the _id field for each inserted document.B. The _id field is required for each document.C. The _id field must be unique.D. The _id field is automatically included and populated with an ObjectId if the _id field is omitted in an inserted document.

Consider the following collection in a MongoDB database:db.students.insertOne( {sno: 1, age: 20, name: "Amy", address: "38 Glenpark Ave"})If we run the following query on this MongoDB database, which fields will this query return for the result?db.students.find({sno:{$in:[ '1', '6' ]}}, {name: 1, address: 1}). 试题 7选择一项或多项：a._idb.addressc.named.all other fields in the documentse.sno

Which of the following field comes by default when you insert one document in the Collection?Answer choicesSelect only one optionREVISITB_noPrimary key_Sno_id

Which of the following is the use of id() function in python?Id() returns the size of object.Id() returns the identity of the object.Both A and BNone of the above

Which of the following is/are correct?试题 6选择一项或多项：a.Dynamo doesn’t require a rigid schema before inserting data.b.MongoDB supports the concepts of primary key and foreign key.c.Google's Bigtable does not support schema.d.The concept of schema in MongoDB is flexible, which allows programmers to modify data structure at runtime.

Which of the following is/are correct?Question 11Select one or more:Select one or more:a.Google's Bigtable does not support schema.b.MongoDB supports the concepts of primary key and foreign key.c.Dynamo doesn’t require a rigid schema before inserting data.d.The concept of schema in MongoDB is flexible, which allows programmers to modify data structure at runtime.