A database must be shut down before the ALTER TABLE command can be executed.
False
You cannot specify the width for a(n) NUMBER column.
False
DML commands are used to create or modify database tables.
False
Data manipulation language commands are used to create or modify database tables.
False
The scale of a NUMBER column indicates the number of digits that can be displayed to the right of the decimal point.
True
The CREATE TABLE command cannot contain a subquery.
False
The scale of a NUMBER column indicates the total number of digits that can be stored in the column.
False
The TRUNCATE TABLE command can be used to delete a table from a database.
False
Seven bytes are allocated in a DATE column to store the century, year, month, day, hour, minute, and second of a date.
True
Every table name within a specific schema must be unique.
True
Using the DESC on a table will display hidden columns.
False
A table must contain a minimum of two columns.
False
A CHAR column cannot be resized to a width that is smaller than the data it already contains.
True
The width of a NUMBER column cannot be changed once it contains data.
False
The MODIFY TABLE command can be used to change the size of a table.
False
The MODIFY clause can be included in the ALTER TABLE command to add a default value to an existing column.
True
SELECT9 is a valid table name.
True
The default size of the CHAR column is 2.
False
DDL commands are used to create or modify database objects.
True
The maximum width of a VARCHAR2 column is 2000 characters.
False
The ALTER TABLE command can be used to rename a table.
False
A table name can be up to 30 characters in length.
True
A datatype identifies the type of data to be stored in a column.
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
If you are creating a new table containing four columns from an existing table and want to change the name of one of the columns when it is created in the new table, add a column list containing ____ names in the CREATE TABLE clause.
D. four
Which of the following datatypes refers to fixed-length character data, where n represents the maximum length of the column?
C. CHAR(n)
Which data dictionary object contains a column named HIDDEN_COLUMN?
A. USER_TAB_COLS.
Which of the following keywords can be used to change the size, datatype, and/or default value of an existing column?
C. MODIFY
What is the maximum width that can be assigned to a DATE column?
D. none of the above
Which of the following keywords is used to remove a database table in Oracle 12c?
A. DROP TABLE
When modifying data in existing columns, which of the following is correct?
B. A column must be as wide as the data it already contains.
Which of the following SQL*Plus commands will display the structure of a table?
A. DESC
Which keywords are used to complete the deletion of a column previously marked with SET UNUSED?
D. DROP UNUSED COLUMNS
Which of the following commands will increase the size of the CITY column in the CUSTOMERS table from 12 to 20 and increase size of the LASTNAME column from 10 to 14?
A. ALTER TABLE customers
MODIFY (city VARCHAR2(+8),
lastname VARCHAR2(+4));
B. ALTER TABLE customers
MODIFY (city (20), lastname (14));
C. ALTER TABLE customers
MODIFY (city VARCHAR2(20),
lastname VARCHAR2(14));
D. ALTER TABLE customers
MODIFY (city (+8),
lastname (+4));
C. ALTER TABLE customers
MODIFY (city VARCHAR2(20),
lastname VARCHAR2(14));
When defining columns for a table, which of the following symbols is used to separate the column names in the column list?
D. ,
When creating a table, which of the following statements is correct?
C. The column list must be enclosed in parentheses ( ).
A _______ column generates values automatically at runtime and may reference values from other columns.
C. Virtual
Which of the following keywords cannot be used to modify an existing table?
D. ALTER TABLE...AS
Which of the following rules does not apply to column names in Oracle 12c?
C. Column names can contain an ampersand (&).
Which of the following is a valid column name?
D. NEW_COLUMN
If a new table is being created based upon a subquery, the subquery must be enclosed in which of the following symbols?
C. ( )
Once a column has been set as UNUSED, which of the following is correct?
D. It is unavailable and will not be displayed in the table structure.
Which of the following datatypes refers to variable-length character data, where n represents the maximum length of the column?
B. VARCHAR2(n)
When using the ALTER TABLE...DROP COLUMN command, which of the following is not correct?
C. The command can be used to delete multiple columns from a table.
Which of the following is displayed by the DESCRIBE command?
