Big Data Integration and Processing Quiz 1 Answer

Big Data Integration and Processing
Quiz 1 Answer

Quiz 1 - Retrieving Big Data Quiz

Q1) What does it mean for a query language to be declarative?

The language specifies the process of how to obtain the data.

The language specifies what data to obtain.

A language specific declaration of data types in order to define the method of data retrieval.

The language specifies both the process of how to obtain the data and specifies what data to obtain.

Q2) Use the following table named "user_table" to answer the next 2 problems.

userId username email

1 admin admin@corporate.moe

2 h4xor 1337@rawr.cte

How would you go about querying the entire username column (however many)?

SELECT user_table FROM username

SELECT username FROM user_table

SELECT username FROM userId WHERE *

SELECT username FROM user_table WHERE userId=1

Q3) How would you go about querying the entire database table (please refer to question 2's table)?

SELECT user_table FROM *

SELECT * FROM user_table

SELECT * FROM * WHERE user_table

SELECT username, email FROM userId

Q4) What is the global indexing table?

An index table in order to keep track of data records within one machine.

An index table in order to keep track of a given data type that might exist within one machine.

A global table that uses a specific technique called indexing and the table uses an index as the primary key.

An index table in order to keep track of a given data type that might exist within multiple machines.

Q5)What are the three computing steps of a semi-join?

Index, Join, Display

Query, Join, Display

None Applicable

Project, Ship, Reduce

Project, Decompose, Send

Q6) What is the purpose of a semi-join?

Increase the efficiency of sending data across multiple machines.

Another name for join: an operation to combine two tables by column.

Increase the speed of the join for trade-off of increased data transmission cost.

Q7) What is a subquery?

A short query than normal.

A query statement within another query.

An alternative query that acts as a substitute for another query.

Q8) What is a correlated subquery?

A type of query that requires two tables in order to calculate values.

A type of query that contains a subquery that requires information from a query one level up.

A type of query that contains a relationship between a variable attribute x and a variable attribute y. The two variables have a dependent relationship causing a correlation.

Q9) What is the purpose of GROUP BY queries?

Enables queries within queries.

Enables calculations based on specific columns of the table.

Required before you can use functions like AVG, SUM, MIN, MAX, COUNT.

Q10) Consider the following generic statement for questions 10-12:
db.<collection>.find(<query filter>, <projection>).<cursor modifier>

Which part of the statement would reflect that of the FROM statement in SQL as illustrated in the lecture?

<query filter>

<collection>

<cursor modifier>

<projection>

Q11) Which part of the statement would reflect that of the SELECT statement in SQL as illustrated in the lecture?

<query filter>

<projection>

<cursor modifier>

<collection>

Q12) Which part of the statement would reflect that of the WHERE statement in SQL as illustrated in the lecture?

<projection>

<cursor modifier>

<query filter>

<collection>

Q13) A sample part of the data structure is as follows:

{ _id:1, userIndex: 10, email: “arealeamil@notreallu.asd", retainRate:2}

What would be the most likely statement that we would need to grab email info for user indexes greater than 24?

db.userIndex.find({email:{$gt:24}}, {_id:0})

db.email.find({userIndex:{$gt:24}}, {email:1, _id:0})

db.userIndex.find({email:{$lte:24}}, {_id:0})

db.email.find({userIndex:{$lte:24}}, {email:1, _id:0})

Q14) What does it mean to have a _id:0 within our query statement?

Grab the first object in the results.

Grab as many objects as possible.

Tell MongoDB not to return a document id.

Does not have an effect, simple convention left for compatibility issues.

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Big Data Integration and Processing