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