Tag: databases

Questions Related to databases

With SQL, how can you insert a new record into the "Persons" table?
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  1. INSERT INTO Persons VALUES ('Jimmy', 'Jackson')

  2. INSERT VALUES ('Jimmy', 'Jackson') INTO Persons

  3. INSERT ('Jimmy', 'Jackson') INTO Persons

  4. INSERT VALUES ('Jimmy', 'Jackson')

Show answer
Correct Option: A

With SQL, how can you insert "Olsen" as the "LastName" in the "Persons" table?

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  1. INSERT INTO Persons (LastName) VALUES ('Olsen')

  2. INSERT ('Olsen') INTO Persons (LastName)

  3. INSERT INTO Persons ('Olsen') INTO LastName

  4. INSERT INTO Persons ('Olsen')

Show answer
Correct Option: A

With SQL, how can you delete the records where the "FirstName" is "Peter" in the Persons Table?

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  1. DELETE ROW FirstName='Peter' FROM Persons

  2. DELETE FROM Persons WHERE FirstName = 'Peter'

  3. DELETE FirstName='Peter' FROM Persons

  4. REMOVE FROM Persons WHERE FirstName = 'Peter'

Show answer
Correct Option: B

AI Explanation

To delete records where the "FirstName" is "Peter" in the Persons table using SQL, you would use the DELETE statement along with the WHERE clause to specify the condition.

Let's go through each option to understand why it is correct or incorrect:

Option A) DELETE ROW FirstName='Peter' FROM Persons - This option is incorrect because the correct syntax for the DELETE statement is DELETE FROM table_name.

Option B) DELETE FROM Persons WHERE FirstName = 'Peter' - This option is correct because it follows the correct syntax for the DELETE statement. It specifies the table name as "Persons" and uses the WHERE clause to specify the condition "FirstName = 'Peter'".

Option C) DELETE FirstName='Peter' FROM Persons - This option is incorrect because the correct syntax for the DELETE statement is DELETE FROM table_name. Additionally, the condition should be specified using the WHERE clause.

Option D) REMOVE FROM Persons WHERE FirstName = 'Peter' - This option is incorrect because the correct keyword to use for deleting records in SQL is DELETE, not REMOVE. The correct syntax should be DELETE FROM table_name.

The correct answer is Option B. This option is correct because it uses the correct syntax for the DELETE statement and specifies the condition using the WHERE clause.

Which SQL statement is used to delete data from a database?

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  1. DELETE

  2. COLLAPSE

  3. REMOVE

  4. ERASE

Show answer
Correct Option: A

With SQL, how do you select a column named "FirstName" from a table named "Persons"?

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  1. EXTRACT FirstName FROM Persons

  2. SELECT FirstName FROM Persons

  3. SELECT Persons.FirstName

  4. SELECT * FROM Persons

Show answer
Correct Option: B

AI Explanation

To select a column named "FirstName" from a table named "Persons" in SQL, you would use the following query:

B. SELECT FirstName FROM Persons

Option A) EXTRACT FirstName FROM Persons - This option is incorrect because the EXTRACT keyword is used to extract specific parts of a date or time, not to select columns from a table.

Option B) SELECT FirstName FROM Persons - This option is correct. It uses the SELECT keyword to specify the column "FirstName" and the FROM keyword to specify the table "Persons".

Option C) SELECT Persons.FirstName - This option is incorrect because it uses the table name "Persons" as a prefix to the column name "FirstName". In SQL, the correct syntax is to specify the column name directly after the SELECT keyword.

Option D) SELECT * FROM Persons - This option is incorrect because it uses the asterisk (*) symbol to select all columns from the table "Persons". To select only the "FirstName" column, you need to specify it explicitly as shown in option B.

The correct answer is B. This option is correct because it uses the correct syntax to select the "FirstName" column from the "Persons" table.

With SQL, how do you select all the records from a table named "Persons" where the "FirstName" is "Peter" and the "LastName" is "Jackson"?
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  1. SELECT * FROM Persons WHERE FirstName='Peter' AND LastName='Jackson'

  2. SELECT FirstName='Peter', LastName='Jackson' FROM Persons

  3. SELECT * FROM Persons WHERE FirstName<>'Peter' AND LastName<>'Jackson'

  4. SELECT * FROM Persons WHERE FirstName='Jackson' AND LastName='Peter'

Show answer
Correct Option: A

With SQL, how do you select all the records from a table named "Persons" where the "LastName" is alphabetically between (and including) "Hansen" and "Pettersen"?

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  1. SELECT * FROM Persons WHERE LastName>'Hansen' AND LastName

  2. SELECT * FROM Persons WHERE LastName BETWEEN 'Hansen' AND 'Pettersen'

  3. SELECT LastName>'Hansen' AND LastName

  4. SELECT LastName<>'Hansen' AND LastName<>'Pettersen' FROM Persons

Show answer
Correct Option: B
Explanation:

To solve this question, the user needs to know the syntax for the SELECT statement in SQL and how to use the WHERE clause to filter records based on a specific condition. The user must also understand the BETWEEN operator in SQL that is used to select values within a range.

Now, let's go through each option and explain why it is right or wrong:

A. SELECT * FROM Persons WHERE LastName>'Hansen' AND LastName'Hansen' AND LastName'Hansen' AND LastName<>'Pettersen' FROM Persons This option is incorrect. The query selects all the records except the records with the last name "Hansen" and "Pettersen" from the "Persons" table, which is not what we want. We need to select records with last name between (and including) "Hansen" and "Pettersen".

The Answer is: B

Which SQL statement defines a FOREIGN KEY constraint on the DEPT NO column of the EMP table?
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  1. CREATE TABLE EMP (empno NUMBER(4), ename VARCHAR2(35), deptno NUMBER(7,2) NOT NULL, CONSTRAINT emp_deptno_fk FOREIGN KEY deptno REFERENCES dept deptno);

  2. CREATE TABLE EMP (empno NUMBER(4), ename VARCHAR2(35), deptno NUMBER(7,2) CONSTRAINT emp_deptno_fk REFERENCES dept (deptno));

  3. CRETE TABLE EM (empno NUMBER(4), ename VARCHAR2(35) deptno NUMBER (7,2) NOT NULL, CONSTRAINT em_deptno_fk REFERENCES dept (deptno) FOREIGN KEY (deptno));

  4. CREATE TABLE EMP (empno NUMBER (4), ename VARCHAR2(35), deptno NUMBER(7,2) FOREIGN KEY CONSTRAINT emp deptno fk REFERENCES dept (deptno));

Show answer
Correct Option: B
Explanation:

To understand this question, the user needs to know how to define foreign key constraints in SQL. A foreign key is a column or combination of columns that is used to establish a link between the data in two tables. The FOREIGN KEY constraint is used to prevent actions that would destroy links between tables.

Let's go through each option and explain why it is right or wrong:

A. CREATE TABLE EMP (empno NUMBER(4), ename VARCHAR2(35), deptno NUMBER(7,2) NOT NULL, CONSTRAINT emp_deptno_fk FOREIGN KEY deptno REFERENCES dept deptno);

This option is incorrect because it has a syntax error. The FOREIGN KEY constraint is not properly defined. It is missing parentheses around the column name, and the table name should be followed by the column name in parentheses.

B. CREATE TABLE EMP (empno NUMBER(4), ename VARCHAR2(35), deptno NUMBER(7,2) CONSTRAINT emp_deptno_fk REFERENCES dept (deptno));

This option is correct. It defines a FOREIGN KEY constraint called emp_deptno_fk on the deptno column of the EMP table. The constraint references the DEPTNO column of the DEPT table.

C. CRETE TABLE EM (empno NUMBER(4), ename VARCHAR2(35) deptno NUMBER (7,2) NOT NULL, CONSTRAINT em_deptno_fk REFERENCES dept (deptno) FOREIGN KEY (deptno));

This option is incorrect because it has a syntax error. The table name is misspelled, and the FOREIGN KEY constraint is not properly defined. It should be defined before the REFERENCES keyword.

D. CREATE TABLE EMP (empno NUMBER (4), ename VARCHAR2(35), deptno NUMBER(7,2) FOREIGN KEY CONSTRAINT emp deptno fk REFERENCES dept (deptno));

This option is incorrect because it has a syntax error. The FOREIGN KEY constraint is not properly defined. It is missing parentheses around the column name, and the table name should be followed by the column name in parentheses.

Therefore, the correct answer is:

The Answer is: B

Evaluate the set of SQL statements: CREATE TABLE dept (deptbi NUMBER (2) dname VARCHAR2(14), Ioc VARCHAR2(13)); ROLLBACK; DESCRIBE DEPT What is true about the set?
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  1. The DESCRIBE DEPT statement displays the structure of the DEPT table

  2. The ROLLBACK statement frees the storage space occupied by the DEPT table.

  3. The DESCRIBE DEPT statement returns an error ORA-04043: object DEPT does not exist

  4. The DESCRIBE DEPT statement displays the structure of the DEPT table only if there is a COMMIT statement introduced before the ROLLBACK statement.

Show answer
Correct Option: A

Which two are attributes of /SQL* Plus? (Choose two).

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  1. /SQL * Plus commands cannot be abbreviated

  2. /SQL* Plus commands are accessed from a browser.

  3. /SQL*Plus commands are used to manipulate data in tables

  4. /SQL* Plus command manipulate table definitions in the database

  5. /SQL* Plus is the Oracle proprietary interface for executing SQL statements.

Show answer
Correct Option: C,E

AI Explanation

To answer this question, let's go through each option to understand why it is correct or incorrect:

Option A) /SQL * Plus commands cannot be abbreviated - This option is incorrect. SQL*Plus commands can be abbreviated using a combination of the first few letters of the command.

Option B) /SQL* Plus commands are accessed from a browser - This option is incorrect. SQL*Plus commands are accessed through a command-line interface, not a browser.

Option C) /SQL*Plus commands are used to manipulate data in tables - This option is correct. SQL*Plus commands are used to interact with the Oracle database, including manipulating data in tables through SQL statements.

Option D) /SQL* Plus commands manipulate table definitions in the database - This option is incorrect. SQL*Plus commands are mainly used to interact with data, not to manipulate table definitions.

Option E) /SQL* Plus is the Oracle proprietary interface for executing SQL statements - This option is correct. SQL*Plus is a command-line interface provided by Oracle for executing SQL statements and managing the Oracle database.

The correct answers are C and E. These options correctly describe attributes of SQL*Plus, as it is used to manipulate data in tables and is the Oracle proprietary interface for executing SQL statements.