External Tables — Learn free

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Questions 1–10 of 10

1. What is an external table?
Question 1A. A table replicated to a second database serverB. A database feature that defines a table structure within the database while the actual data is stored externally, typically in filesC. A temporary table created inside a stored procedureD. A table whose rows are encrypted at restE. A view that combines two or more tables
2. Which file formats are given as examples of externally stored data that external tables can query?
Question 2A. DOCX, PPTX and XLSXB. MP3, MP4 and WAVC. CSV, Parquet and JSOND. EXE, DLL and BINE. HTML, CSS and JavaScript
3. Which storage systems are named as examples of where external data files may reside?
Question 3A. A local USB drive and a DVDB. An email server and a fax machineC. A mainframe tape libraryD. HDFS, Amazon S3 or Azure Blob StorageE. A relational database's system tablespace
4. What two things must be specified to create an external table?
Question 4A. A primary key and a foreign keyB. A refresh schedule and a retention policyC. An index and a partition keyD. A username and a passwordE. The table structure (columns and data types) and a location pointing to the external storage
5. In the CustomerData example, what does the LOCATION clause indicate?
Question 5A. The directory where the external data files are storedB. The database schema that owns the tableC. The server region for replicationD. The name of the backup folderE. The column used for partitioning
6. How is an external table queried once it has been created?
Question 6A. Only by importing the files into a regular table firstB. Using SQL just like any other regular table, with the engine fetching data from the external filesC. Only through a file-system commandD. By running a REFRESH command before each queryE. Only through a view built on top of it
7. Why are external tables described as cost-effective?
Question 7A. They compress data automaticallyB. They eliminate the need for a database engineC. They let you use cost-effective external storage for large datasets without duplicating the data inside the databaseD. They are free of licensing feesE. They reduce the number of columns needed
8. What does the HighValueCustomers example create?
Question 8A. A new external table in a different locationB. A materialised view refreshed dailyC. An index on PurchaseAmountD. A view on top of the external table CustomerData that filters customers with PurchaseAmount above 1000E. A backup copy of CustomerData
9. What benefit does creating a view over an external table provide?
Question 9A. It moves the data into the database permanentlyB. It encrypts the external filesC. It removes the need for a LOCATION clauseD. It makes the external files read-onlyE. It defines a logical layer over the external data and simplifies querying
10. Which of the following is NOT a stated advantage of external tables?
Question 10A. Automatic real-time refresh of a stored snapshotB. Cost-effective storageC. Ease of data management for massive datasetsD. Integration with external storage systemsE. Flexibility in data storage