Querying Modifying LOBs - Quiz Explanation

The correct answers are indicated below, along with text that explains the correct answers.

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1.	What is the difference between an internal and an external LOB? Please select the best answer.
	A.	An internal LOB is maintained with the object table data, whereas an external LOB is maintained within a separate tablespace.
	B.	An internal LOB is maintained within the operating system of the database, whereas an external LOB is maintained within the network outside the server, which hosts the database.
	C.	An internal LOB is maintained inside the database, whereas an external LOB is maintained outside the database.
	D.	An external LOB is maintained within the database, whereas an internal LOB is maintained inside the server, but outside the database.
	C is the correct answer. An internal LOB is maintained inside the database, whereas an external LOB is maintained outside the database, so answer C is correct. Answer A is incorrect because an external LOB is not maintained within a separate tablespace. Answer B is incorrect because an internal LOB exists only inside the database, and an external LOB can occur anywhere outside the database, such as within the network, within a CD, or on the file system of the same server as the database. Answer D is incorrect because the information is reversed.

2.	What is the difference between CLOB and NCLOB? Please select the best answer.
	A.	CLOB is character-based LOB, whereas NCLOB is natural-character-based LOB.
	B.	NCLOB is based on the national character set, whereas CLOB is based on the character set defined in the creation of the database.
	C.	CLOB has binary data, whereas NCLOB has character-based data.
	D.	NCLOB is based on raw data, whereas CLOB is based on character data.
	Answer B is correct, because CLOB is character based, whereas NCLOB is based on the national character set. Answer A is incorrect because NCLOB is based on the national character set. Answer C is incorrect because BLOB, not CLOB, is based on binary data. Answer D is incorrect because BLOB, not NCLOB, is based on raw binary data.

3.	What are the two ways of loading data into LOB columns? Please select the best answer.
	A.	`INSERT` statements and Oracle Export and Import..
	B.	SQL*Loader and DBMS_LOB.
	C.	Oracle Backup utility and Oracle Export and Import.
	D.	LOB data cannot be loaded into an Oracle database.
	Answer B is correct The procedures an4 functions provided within `DBMS_LOB` and SQLLoader utilities are the only two means to load data into LOB columns, so answer B is correct. Answer A is incorrect because Oracle Export and Import cannot be used to load the LOB columns. The Oracle Export and Import utility is used for archiving data. Answer C is incorrect because both Oracle Backup and Export and Import cannot be used to load the LOB data because they are used for archiving data. Answer D is incorrect because the LOB data can be loaded into the database by using `DBMS_LOB` and SQLLoader.

4.	What is the utility of `DBMS_LOB`? Please select the best answer.
	A.	`DBMS_LOB` is used only for loading data into the LOB columns.
	B.	Data can be erased and updated by using `DBMS_LOB`.
	C.	`DBMS_LOB` is a package used for displaying the LOB data.
	D.	`DBMS_LOB` is a package that has several utilities on internal and external LOBs, including reading, writing, appending, and erasing LOB data among other utilities.
	Answer D is correct DBMS_LOB is used in several different places to operate on internal and external LOBs, so answer D is correct. Answer A is incorrect because loading data is not the only purpose of DBMS_LOB. Answer B is incorrect because DBMS_LOB performs a number of operations on `BLOB`, `CLOB`, `NCLOB`, and `BFILE` data types. Answer C is incorrect because LOB data can be displayed by front-end applications only.