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Hadoopdata~20 mins

External vs managed tables in Hadoop - Practice Questions

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Challenge - 5 Problems
🎖️
Table Mastery in Hadoop
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Test your skills under time pressure!
🧠 Conceptual
intermediate
2:00remaining
Difference in data deletion behavior

When you drop a managed table in Hadoop, what happens to the underlying data files?

AThe data files are moved to a backup location automatically.
BOnly the table metadata is deleted; data files remain untouched.
CThe data files are archived but not deleted.
DThe data files are deleted along with the table metadata.
Attempts:
2 left
💡 Hint

Think about who controls the data lifecycle in managed tables.

🧠 Conceptual
intermediate
2:00remaining
Location of data for external tables

Where is the data stored for an external table in Hadoop?

AIn a user-specified location outside the warehouse directory.
BIn the default warehouse directory managed by Hadoop.
CIn a temporary directory that is deleted after use.
DIn the Hadoop system memory only.
Attempts:
2 left
💡 Hint

External tables allow you to keep data where you want.

❓ data_output
advanced
2:00remaining
Effect of dropping external table

Given an external table pointing to data at /user/data/sales, what happens to the data files if you run DROP TABLE external_sales;?

Hadoop
CREATE EXTERNAL TABLE external_sales(id INT, amount FLOAT) LOCATION '/user/data/sales';
-- Then run:
DROP TABLE external_sales;
AAn error occurs because external tables cannot be dropped.
BOnly table metadata is deleted; data files remain at /user/data/sales.
CData files are moved to a temporary backup folder.
DData files at /user/data/sales are deleted.
Attempts:
2 left
💡 Hint

Dropping external tables affects metadata only.

🔧 Debug
advanced
2:00remaining
Unexpected data loss after dropping table

A user created a managed table and loaded data into it. After dropping the table, the data files are missing. What is the most likely cause?

AThe table was external, but the data was manually deleted.
BThe DROP TABLE command only deletes metadata, so data loss is impossible.
CThe table was managed, so dropping it deleted the data files.
DThe data files were stored outside the warehouse directory.
Attempts:
2 left
💡 Hint

Recall the difference in data handling between managed and external tables.

🚀 Application
expert
2:00remaining
Choosing table type for data sharing

You want to create a table in Hadoop that allows multiple teams to access shared data without risk of accidental deletion of the data files. Which table type should you choose?

AExternal table, because it keeps data files separate from metadata management.
BManaged table, because it handles data lifecycle automatically.
CTemporary table, because it is session-specific and safe.
DPartitioned managed table, because partitions isolate data.
Attempts:
2 left
💡 Hint

Think about which table type protects data files from deletion when dropped.