Table Creation and Management
The ____________________ datatype is used to store fixed length data.
CHAR
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
Structure of the PROMOTION table Which of the following SQL statements was most likely used to create the PROMOTION table?
CREATE TABLE promotion (gift VARCHAR2(15), minretail NUMBER(5, 2), maxretail NUMBER(5, 2));
Which of the following keywords can be used to change the size, datatype, and/or default value of an existing column?
MODIFY
Which of the following is a valid table name?
MYTABLE
Which of the following rules apply to table names in Oracle 12c?
Names can contain a number sign (#)
Structure of the PROMOTION table Which of the following commands will change the name of the PROMOTION table to GIFT?
RENAME promotion TO gift
Which of the following is a valid table name in Oracle 12c?
S_c#oT#2t_321sM#_i_T6h
The ____________________ TABLE command can be used to delete and release the storage space of all data contained in a database table, while still retaining the table's structure.
TRUNCATE
Structure of the PROMOTION table Which data dictionary object contains a column named HIDDEN_COLUMN?
USER_TAB_COLS
Which of the following is displayed by the DESCRIBE command?
all of the above
If you are creating a new table from data contained in an existing table, new column names can be specified by including a list of column names ____.
before the AS clause
Structure of the CUSTOMERS table Which of the following commands will display the structure of the CUSTOMERS table?
both a and b
Each ____________________ name within a table must be unique.
column
A column's ____________________ identifies the type of data that can be stored in a column.
data type
A(n) ____ simply identifies the type of data that Oracle 12c will be expected to store in a column.
datatype
Once a table is ____________________, any associated indexes will be removed from the database.
dropped or deleted
A column name can consist of up to 225 characters.
false
A table must contain a minimum of two columns. _________________________
false
Data manipulation language commands are used to create or modify database tables. _________________________
false
If the CREATE TABLE is being used to create a table from existing data, the SUBQUERY keyword must be used.
false
The ALTER TABLE name can be used to rename a table.
false
The CHANGE TABLE command can be used to modify an existing table. _________________________
false
The CHAR datatype is used to store variable-length data that can consist of letters and numbers. _________________________
false
The MODIFY TABLE command can be used to change the size of a table.
false
The MODIFY clause can be used with the ALTER TABLE command to add a column to an existing table. _________________________
false
The TRUNCATE TABLE command can be used to delete 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 maximum width of a(n) CHAR column is 4000 characters. _________________________
false
The width of a NUMBER column cannot be changed once it contains data. _________________________
false
To retain the structure of a table, while deleting all its data and releasing their storage space, execute the TRUNC command.
false
Using the DESC on a table will display hidden columns.
false
You cannot specify the width for a(n) NUMBER column. _________________________
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
Structure of the CUSTOMERS table 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
What is the maximum width that can be assigned to a DATE column?
none of the above
A database ____________________ is a defined, self-contained structure in Oracle 12c.
object
A CHAR column cannot be resized to a width that is smaller than the data it already contains.
true
A database object is a defined, self-contained structure in Oracle 12c.
true
A datatype identifies the type of data to be stored in a column.
true
SELECT9 is a valid table name
true
Seven bytes are allocated in a DATE column to store the century, year, month, day, hour, minute, and second of a date. _________________________
true
The CREATE TABLE command is used to create a table in Oracle 12c. _________________________
true
The DROP COLUMN clause of the ALTER TABLE command can only be used to delete one column at a time. _________________________
true
The DROP TABLE command can be used to remove a table and all its data from a database.
true
The INTERVAL datatype can be used to identify a specific interval, or amount, of time.
true
The MODIFY clause can be included in the ALTER TABLE command to add a default value to an existing column. _________________________
true
The USER_TAB_COLS data dictionary object contains a column to identify hidden columns.
true
The default format of a DATE column in Oracle 12c is DD-MON-YY.
true
The precision of a NUMBER does not include the decimal point itself in the total number of digits that can be stored in a column.
true
You cannot delete the last column in a table.
true
When modifying data in existing columns, which of the following is correct?
A column must be as wide as the data it already contains.
Structure of the CUSTOMERS table 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?
ALTER TABLE customers MODIFY (city VARCHAR2(20), lastname VARCHAR2(14));
Which of the following commands will drop any columns marked as unused from the TABLEA table?
ALTER TABLE tablea DROP UNUSED COLUMNS;
Which of the following keywords cannot be used to modify an existing table?
ALTER TABLE...AS
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 is a valid SQL statement?
CREATE TABLE newname (colA NUMBER, colB DATE);
Which of the following keywords uses a subquery to create a new table using existing database tables?
CREATE TABLE...AS
Which of the following rules does not apply to column names in Oracle 12c?
Column names can contain an ampersand (&).
Which keywords are used to complete the deletion of a column previously marked with SET UNUSED?
DROP UNUSED COLUMNS
Once a column has been set as UNUSED, which of the following is correct?
It is unavailable and will not be displayed in the table structure.
Structure of the PROMOTION table Which of the following commands will change the name of the PROMOTION table to GIFT?
RENAME promotion TO gift;
Structure of the PROMOTION table Which of the following queries will allow hidden columns to be displayed?
SELECT which specifically references the hidden column.
If a column is defined as NUMBER(5,2), which of the following is true?
The column can store a total of 5 digits, with 3 on the left side of the decimal point, and 2 on the right.
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)
Structure of the PROMOTION table 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 terms refers to commands that are used to create or modify database tables?
data definition language (DDL)
If a new table is being created based upon a subquery, the subquery must be enclosed in which of the following symbols?
( )
The column list of the CREATE TABLE command must be enclosed in ____________________.
( ) or parentheses
When defining columns for a table, which of the following symbols is used to separate the column names in the column list?
,
The DROP COLUMN clause of the ALTER TABLE command can be used to drop a maximum of ____________________ column(s) at a time.
1 or one
The maximum width of the NUMBER datatype is ____ digits.
38
The column definition of NUMBER(7, 4) indicates a precision of ____.
7
When adding a column to an existing table, the ____________________ clause must be used with the ALTER TABLE command.
ADD
The ____________________ command can be used to modify the structure of a table.
ALTER TABLE
Which of the following commands can be used to make structural changes to an existing table?
ALTER TABLE
Structure of the CUSTOMERS table 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?
ALTER TABLE customers MODIFY (city VARCHAR2(20), lastname VARCHAR2(14));
The ____________________ keyword must be used with the CREATE TABLE command if the table is being created from a subquery.
AS
The structure of a table can be viewed by issuing the STRUCTURE command.
FALSE
In which format does Oracle 12c display a date value?
DD-MON-YY
_________________________ commands are used to create database objects.
DDL or Data Definition Language
Which of the following SQL*Plus commands will display the structure of a table?
DESC
The ____________________ TABLE command can be used to delete a table from a database.
DROP
The ____________________ clause of the ALTER TABLE command can be used to delete a column from an existing table.
DROP COLUMN