Managing Databases with Oracle Questions and Answers

Q: Oracle will let you define Notepad as your default editor, and whenever you type NOTEPAD, SQL*Plus will invoke Notepad.

Correct answer: FalseThe first half is right and the second wrong. An editor is defined once, with DEFINE _EDITOR, and is then invoked by typing EDIT - not by typing the editor’s own name, which SQL*Plus would not recognise as a command. The point of the arrangement is that scripts using EDIT work whatever editor has been chosen.

Q: You can check on the status of tables with the DESCRIBE or DESC command.

Correct answer: TrueDESCRIBE, abbreviated DESC, lists the columns of a table or view with their datatypes and their nullability. It is the quickest way of confirming what a table actually contains before writing a statement against it, and it works on views and procedures too.

Q: Oracle allows the ORDER BY clause in view definitions.

Correct answer: TrueThis is the exception to the standard. SQL-92 forbids ORDER BY in a view definition, on the ground that a view is a relation and a relation is unordered; Oracle permits it. Note that the ordering is not guaranteed to survive a query against the view that imposes its own ordering or joins to something else.

Q: The Oracle ROLLBACK statement makes all changes since the last COMMIT permanent.

Correct answer: FalseROLLBACK does the opposite, discarding every uncommitted change and restoring the data to its state at the last COMMIT. It is COMMIT that makes changes permanent and visible to other sessions.

Q: You have linked SQL*Plus to an external text editor. To invoke the text editor for use within SQL*Plus, which command do you use?

Correct answer: Edit [ FileName ]The EDIT command opens the external editor that has been defined for SQL*Plus, either on the named file or on the current buffer. The name of the editor itself is never typed as a command; it is set once with DEFINE _EDITOR, and EDIT then invokes whatever was set.

Q: When using SQL*Plus, Oracle commands, column names, table names and all other database elements:

Correct answer: are case insensitive.SQL keywords, table names, column names and other identifiers are matched without regard to case, so SELECT, select and Select are the same, as are CUSTOMER and customer. Case matters only inside quoted string literals, where the characters are data, and in identifiers deliberately created within double quotes.

21.

In creating a procedure, you may get a message if you have compile errors. Which of the following is true?

A.The line numbers reported match the line numbers you see in your text editor.
B.SQL*Plus will automatically show the errors to you.
C.To see the errors, enter SHOW ERRORS in SQL*Plus.
D.If there are no syntax errors, you will receive the message "NO ERRORS."

Answer: C

Correct answer: To see the errors, enter SHOW ERRORS in SQL*Plus.

SQL*Plus reports only that the procedure was created with compilation errors; the errors themselves must be asked for with SHOW ERRORS. The line numbers it then gives are counted from the start of the CREATE statement, which will not match a text editor’s numbering unless the statement begins on line one of the file.

Discuss in Forum

22.

Oracle will let you define Notepad as your default editor, and whenever you type NOTEPAD, SQL*Plus will invoke Notepad.

A.True
B.False

Answer: B

Correct answer: False

The first half is right and the second wrong. An editor is defined once, with DEFINE _EDITOR, and is then invoked by typing EDIT - not by typing the editor’s own name, which SQL*Plus would not recognise as a command. The point of the arrangement is that scripts using EDIT work whatever editor has been chosen.

Discuss in Forum

23.

You can check on the status of tables with the DESCRIBE or DESC command.

A.True
B.False

Answer: A

Correct answer: True

DESCRIBE, abbreviated DESC, lists the columns of a table or view with their datatypes and their nullability. It is the quickest way of confirming what a table actually contains before writing a statement against it, and it works on views and procedures too.

Discuss in Forum

24.

Oracle allows the ORDER BY clause in view definitions.

A.True
B.False

Answer: A

Correct answer: True

This is the exception to the standard. SQL-92 forbids ORDER BY in a view definition, on the ground that a view is a relation and a relation is unordered; Oracle permits it. Note that the ordering is not guaranteed to survive a query against the view that imposes its own ordering or joins to something else.

Discuss in Forum

25.

The Oracle ROLLBACK statement makes all changes since the last COMMIT permanent.

A.True
B.False

Answer: B

Correct answer: False

ROLLBACK does the opposite, discarding every uncommitted change and restoring the data to its state at the last COMMIT. It is COMMIT that makes changes permanent and visible to other sessions.

Discuss in Forum

26.

You have linked SQL*Plus to an external text editor. To invoke the text editor for use within SQL*Plus, which command do you use?

A.Open [FileName]
B.Show [FileName]
C.Alter [FileName]
D.Edit [FileName]

Answer: D

Correct answer: Edit [ FileName ]

The EDIT command opens the external editor that has been defined for SQL*Plus, either on the named file or on the current buffer. The name of the editor itself is never typed as a command; it is set once with DEFINE _EDITOR, and EDIT then invokes whatever was set.

Discuss in Forum

27.

An Oracle System Change Number (SCN):

A.is a value that is incremented whenever a dirty read occurs.
B.is incremented whenever a deadlock occurs.
C.is a value that keeps track of explicit locks.
D.is a value that is incremented whenever database changes are made.

Answer: D

Correct answer: is a value that is incremented whenever database changes are made.

The system change number is a database-wide counter advanced whenever a change is committed, and it stamps every change in the redo stream and every datafile header. It is what allows Oracle to establish the ordering of changes, to determine whether a set of files is consistent, and to recover to a chosen point in time.

Discuss in Forum

28.

Which of the following is not true of SQL views?

A.Oracle views cannot use the ORDER BY clause in view definitions.
B.Oracle views are created using the standard SQL-92 CREATE VIEW command.
C.Oracle views can by queried.
D.The SQL-92 standard does not allow the use of the ORDER BY clause in view definitions.

Answer: A

Correct answer: Oracle views cannot use the ORDER BY clause in view definitions.

This is the statement that is not true, and it is the one place where Oracle departs from the standard in the permissive direction. SQL-92 forbids ORDER BY in a view definition, on the ground that a view is a relation and a relation has no order; Oracle allows it, which is convenient and is the exception the item is testing.

Discuss in Forum

29.

When using SQL*Plus, Oracle commands, column names, table names and all other database elements:

A.are case insensitive.
B.are case sensitive.
C.must always be in lower case.
D.must always be in upper case.

Answer: A

Correct answer: are case insensitive.

SQL keywords, table names, column names and other identifiers are matched without regard to case, so SELECT, select and Select are the same, as are CUSTOMER and customer. Case matters only inside quoted string literals, where the characters are data, and in identifiers deliberately created within double quotes.

Discuss in Forum

30.

Which of the following is not true about modifying table columns?

A.You can drop a column at any time.
B.You can add a column at any time as long as it is a NULL column.
C.You can increase the number of characters in character columns or the number of digits in numeric columns
D.You cannot increase or decrease the number of decimal places.

Answer: D

Correct answer: You cannot increase or decrease the number of decimal places.

This is the statement that is untrue: the scale of a numeric column can be altered, subject to the existing data fitting. The other three hold - a column may be dropped, a column may be added provided it allows nulls or a default is supplied, and character length and numeric precision may be increased freely.

Discuss in Forum

Loading…

Topics

Other Subjects

Tags: Managing Databases with Oracle Questions and Answers || Managing Databases with Oracle MCQ Questions and Answers || Managing Databases with Oracle GK Questions and Answers || Managing Databases with Oracle GK MCQ Questions || Managing Databases with Oracle Multiple Choice Questions and Answers || Managing Databases with Oracle GK || GK on Managing Databases with Oracle || Database Questions and Answers || Database MCQ Questions and Answers || Database GK Questions and Answers || GK on Database

Managing Databases with Oracle Questions and Answers

Topics

Other Subjects

About Us

Stay informed about all important Dates & Notifications