Oracle 12c: SQL - Chapter 3

A column name can consist of up to 225 characters.

False

A database must be shut down before the ALTER TABLE command can be executed.

False

A table name can consist of numbers, letters, and blank spaces.

False

A table name must begin with a(n) *number*.

False

An automatic column will generate a value at runtime and may reference values from other columns.

False

Only one column can be added to an existing table at one time.

False

The *scale* of a NUMBER column indicates the total number of digits that can be stored in the column.

False

The ALPHANUMERIC datatype can be used to store characters and numbers to a maximum width of 2000.

False

The CREATE TABLE cannot contain a subquery.

False

The DELETE TABLE command can be used to delete all the data stored in a table and release the storage space, yet retain the structure of the table.

False

The DELETE TABLE command can be used to remove a table from a database.

False

The data contained in a dropped table can be retrieved if the *DROP* option was not used in the DROP TABLE command.

False

The default size of the CHAR column is *2*.

False

The width of a NUMBER column cannot be *changed* once it contains data.

False

You cannot specify the width for a(n) *NUMBER* column.

False

*DDL* commands are used to create or modify database objects.

True

Every table name within a specific schema must be unique.

True

More than one column can be changed at a time with the *ALTER TABLE...MODIFY* command.

True

Once a column as been set as *UNUSED*, it cannot be recovered.

True

SELECT9 *is* a valid table name.

True

The *MODIFY* clause can be included in the ALTER TABLE command to add a default value to an existing column.

True

The INTERVAL datatype can be used to identify a specific interval, or amount, of time.

True

The syntax of the *CREATE TABLE* command requires that the column list be enclosed in parentheses.

True

When a column is deleted, the deletion is permanent.

True

You cannot delete the last column in a table.

True

Which of the following symbols cannot be used in a table name?

​%

If a new table is being created based upon a subquery, the subquery must be enclosed in which of the following symbols?

​( )

The maximum width of the NUMBER datatype is ____ digits.

​38

Which of the following commands can be used to make structural changes to an existing table?

​ALTER TABLE

Which of the following commands will add a new column named FIRST ORDER DATE to the CUSTOMERS table to store the date that the customer first placed an order with the company?

​ALTER TABLE customers ADD (firstorderdate DATE);

If the MAXRETAIL column of the PROMOTION table has been set as unused, which of the following commands is valid?

​ALTER TABLE promotion DROP UNUSED COLUMNS;

Which of the following keywords is used to mark a column for deletion at a later time?

​ALTER TABLE...SET UNUSED

Which of the following datatypes refers to fixed-length character data, where n represents the maximum length of the column?

​CHAR(n)

Which command instructs Oracle 12c to create a new table?

​CREATE TABLE

Which command instructs Oracle 12c to create a new table from existing data?

​CREATE TABLE...AS

Which of the following keywords uses a subquery to create a new table using existing database tables?

​CREATE TABLE...AS

In which format does Oracle 12c display a date value?

​DD-MON-YY

Which keywords are used to complete the deletion of a column previously marked with SET UNUSED?

​DROP UNUSED COLUMNS

Which of the following is a valid column name?

​NEW_COLUMN

Which command is used to rename a table you own?

​RENAME...TO

Which of the following queries will allow hidden columns to be displayed?

​SELECT which specifically references the hidden column.

When creating a table, which of the following statements is correct?

​The column list must be enclosed in parentheses ( ).

When using the ALTER TABLE...DROP COLUMN command, which of the following is not correct?

​The command can be used to delete multiple columns from a table.

Which of the following datatypes refers to variable-length character data, where n represents the maximum length of the column?

​VARCHAR2(n)

A _______ column generates values automatically at runtime and may reference values from other columns.

​Virtual

If a new column is added to the PROMOTION table, where will the new column be listed?

​after the MAXRETAIL column

Which of the following is displayed by the DESCRIBE command?

​all of the above

Which of the following commands will set the MINRETAIL column of the PROMOTION table as unused?

​both a and c

A(n) ____ simply identifies the type of data that Oracle 12c will be expected to store in a column.

​datatype

Which of the following commands will change the name of the LAST NAME column to LAST_NAME in the CUSTOMERS table?

​none of the above