Accessing Hadoop Data Using Hive Cognitive Class Exam Answers

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Introduction to Accessing Hadoop Data Using Hive

Accessing Hadoop data using Hive is a common and efficient way to interact with large datasets stored in Hadoop Distributed File System (HDFS). Hive provides a SQL-like interface to query data stored in Hadoop, making it accessible to those familiar with SQL but not necessarily with Hadoop’s complex MapReduce programming model.

Understanding Hive

Hive is a data warehouse infrastructure built on top of Hadoop. It provides:

1. SQL Interface: Users can write queries in HiveQL (Hive Query Language), which is similar to SQL, to analyze data stored in Hadoop.
2. Schema on Read: Unlike traditional databases that enforce schema at write-time, Hive allows you to apply a schema when reading data stored in various formats (like JSON, CSV, etc.) from HDFS.
3. Optimized Execution: Under the hood, Hive translates HiveQL queries into MapReduce jobs (or other execution engines like Tez or Spark SQL), optimizing data retrieval and processing.

Accessing Hadoop Data Using Hive

Here’s a basic overview of how you can start accessing Hadoop data using Hive:

1. Set Up Hive: Ensure that Hive is installed and configured on your Hadoop cluster. Hive uses HDFS to store its data, so Hadoop must be up and running.
2. Create Tables: In Hive, you define tables that map to files in HDFS. You can create tables using HiveQL, specifying the file format, columns, and other attributes.sqlCopy codeCREATE TABLE my_table ( id INT, name STRING, age INT ) ROW FORMAT DELIMITED FIELDS TERMINATED BY ',' STORED AS TEXTFILE; This example creates a table named my_table with columns id, name, and age, where data is stored as text files in CSV format.
3. Load Data: Once tables are created, you can load data into them from files stored in HDFS.sqlCopy codeLOAD DATA INPATH '/path/to/data/file' INTO TABLE my_table; This command loads data from the specified HDFS path into the my_table table.
4. Query Data: Use HiveQL to query the data stored in Hadoop. Queries can range from simple SELECT statements to complex aggregations and joins.sqlCopy codeSELECT * FROM my_table WHERE age > 25; This example retrieves all rows from my_table where the age column is greater than 25.
5. Optimize Performance: Hive allows for performance optimization through techniques like partitioning, bucketing, and indexing. These techniques help reduce query latency and improve overall efficiency.

Conclusion

Using Hive to access Hadoop data provides a convenient and powerful way to leverage the scalability and fault-tolerance of Hadoop while providing a familiar SQL interface. It abstracts away the complexities of Hadoop’s underlying infrastructure, making big data processing more accessible to data analysts and SQL developers. As you delve deeper, you’ll discover more advanced features and optimizations that can further enhance your data querying and processing capabilities.

Accessing Hadoop Data Using Hive Cognitive Class Certification Answers

Module 1 – Introduction to Hive Quiz Answers

Question 1: Which company first developed Hive?

• Starbucks
• Facebook
• HP
• Yahoo

Question 2: Hive is a Data Warehouse system built on top of Hadoop. True or false?

• True
• False

Question 3: Which of the following is NOT a valid Hive Metastore config?

• Server Metastore
• Local Metastore
• Remote Metastore
• Embedded Metastore

Module 2 – Hive DDL Quiz Answers

Question 1: Which of the following commands will list the databases in the Hive system?

• DISPLAY ALL DB;
• SHOW ME THE DATABASES;
• DISPLAY DB;
• SHOW DATABASES;

Question 2: MAPS are a Hive complex data type. True or false?

• True
• False

Question 3: An index can be created on a Hive table. True or false?

• True
• False

Module 3 – Hive DML Quiz Answers

Question 1: LOAD DATA LOCAL means that the data should be loaded from HDFS. True or false?

• True
• False

Question 2: Which of the following commands is used to generate a Hive query plan?

• QUERYPLAN
• SHOWME
• HOW
• EXPLAIN

Question 3: Data can be exported out of Hive. True or false?

• True
• False

Module 4 – Hive Operators and Function Quiz Answers

Question 1: Which of the following is NOT a built-in Hive function?

• triplemultiple
• floor
• upper
• round

Question 2: Users can create their own custom user defined functions. True or false?

• True
• False

Question 3: Which of the following is NOT a valid Hive relational operator?

• A ATE B
• A IS NOT NULL
• A LIKE B
• A IS NULL

Accessing Hadoop Data Using Hive Final Exam Answers

Question 1: What is the primary purpose of Hive in the Hadoop architecture?

• To provide logging support for Hadoop jobs
• To support the execution of workflows consisting of a collection of actions
• To support SQL-like queries of data stored in Hadoop in place of writing MapReduce applications
• To move data into HDFS

Question 2: Hive is SQL-92 compliant and supports row-level inserts, updates, and deletes. True or false?

• True
• False

Question 3: In a production setting, you should configure the Hive metastore as

• Remote
• Local
• Embedded
• None of the above

Question 4: The Hive Command Line Interface (CLI) allows you to

• retrieve query explain plans
• view and manipulate table metadata
• perform queries, DML, and DDL
• All of the above

Question 5: When using the Hive CLI, which option allows you to execute HiveQL that’s saved in a text file?

• hive -d
• hive -S
• hive -e
• hive -f

Question 6: Which statement is true of “Managed” tables in Hive?

• Dropping a table deletes the table’s metadata, NOT the actual data
• You can easily share your data with other Hadoop tools
• Table data is stored in a directory outside of Hive
• None of the Above

Question 7: Hive Data Types include

• Maps
• Arrays
• Structs
• A subset of RDBMS primitive types
• All of the Above

Question 8: The PARTITION BY clause in Hive can be used to improve performance by storing all the data associated with a specified column’s value in the same folder. True or false?

• True
• False

Question 9: The LOAD DATA LOCAL command in Hive is used to move a datafile in HDFS into a Hive table structure. True or false?

• True
• False

Question 10: The INSERT OVERWRITE LOCAL DIRECTORY command in Hive is used to

• copy data into an externally managed table
• load data into a Hive Table
• append rows to an existing Hive Table
• export data from Hive to the local file system

Question 11: Hive supports which type of join?

• Left Semi-Join
• Inner Join
• Full Outer Join
• Equi-join
• All of the Above

Question 12: With Hive, you can write your own user defined functions in Java and invoke them using HiveQL. True or false?

• True
• False

Question 13: Which of the following is a valid Hive operator for complex data types?

• S.x where S is a struct and x is the name of the field you wish to retrieve
• M[k] where M is a map and k is a key value
• A[n] where A is an array and n is an int
• All of the above