ObjectId “52cdde87” , “fname”: If you specify no projection, the find method returns all fields of all documents that match the query. A typical loop through results looks like the following: MongoDB supports MapReduce and other aggregation tools. Indexes provide high performance read operations for frequently used queries. Please query the video.

For this question you will use the aggregation framework to figure out pairs of people that tend to communicate a lot. Please query the video. Build Indexes in the Background. When you are done removing the orphan images from the collection, there should be 90, documents in the images collection. Remove Documents that Matches a Condition: You will need to fix that in a stage of the aggregation before doing your grouping and counting of sender, recipient pairs. Use mongorestore to restore the dump into your running mongod.

MongoDB Java

Create an Auto-Incrementing Sequence Field: For basic concepts and options, see Indexing Overview. Job is already running: There is also a views directory which contains the templates for the project. The query returneddocuments Choice 4.

homework 2.2 mongodb java

ObjectId “52c52ae2ead11dc53″”hello”: Import it into your mongod using the following command from the command line: We will take that to mean they don’t really live in a city. Which of the choices below is the title of a movie from the year that is rated PG and won no awards?


Now it’s your turn to analyze the data set.

MongodbChamps: MJ: MongoDB for Java Developers Homework

MongoDB Java Unknown ObjectId “52c52addead11dc51″”egg”: Has no effect on update operations that modify existing documents. Remove all indexes from the collection Choice 5: Install MongoDB on your computer and run it on the standard port.

Model Data for Atomic Operations. Enhancing the Blog to support viewers liking certain comments In this problem, you will be enhancing the blog project to support users liking certain comments and the like counts showing up the in the permalink page.

homework 2.2 mongodb java

Limit Number of Elements in an Array mongofb an Update: Check all that apply. If everything works, you should see your username when you are redirected to the welcome page. ObjectId “52c52addead11dc52″”type”: Newer Post Older Post Home.

MongodbChamps: MJ: MongoDB for Java Developers : Homework

The templates comprise the view. Enron was an American corporation that engaged in a widespread accounting fraud and subsequently failed.


Please query the video. Please use the Enron dataset you imported for the previous problem. Return All Fields in Matching Documents: If everything is working properly, you should be able to start the blog by typing: Blog User Sign-up and Login Download the handout and unpack it.

To create a cursor with the shell, put some documents into a collection, do a query on them, and assign the results to a local variable variables defined with “var” are local. Start by using mongoimport to import your albums.

homework 2.2 mongodb java

Blogger Comment Facebook Comment. Perform Two Phase Commits: The correct result will be: A typical loop through results looks like the following: