Ch. 2 Flashcards
Which of the following would be an invalid column or table name? select all that apply
- P!nk
- 21PILOTS
- BrunoMar$
- Lady-Gaga
- P!nk
- 21PILOTS
- Lady-Gaga
Which of the following data type(s) is(are) supported by Oracle?
- NCLOB
- NUMBER
- CHAR
- STRING
- TIME ZONE(n) WITH TIMESTAMP
- NCLOB
- NUMBER
- CHAR
Which two constraints are combined to implement a primary key?
- UNIQUE
- NOT NULL
- FOREIGN KEY
- CHECK
- UNIQUE
- NOT NULL
The difference between dropping a column from a table with DROP and setting the column to UNUSED is:
The UNUSED column and its data are retained within the table’s storage allocation and counts against the total limit on the number of columns that a table is allowed to have, but no longer appears within the table’s description as shown with a DESC or DESCRIBE
Which of the following is the recommended constraint for the SHIPS table having Primary key SHIP_ID?
- ship_id_PK
- ships_id_PK
- PRIMARY KEY(Ship_id)
- Ships_Ship_ID_PK
- Ships_Ship_ID_PK
DDL statements when executed, will also cause a COMMIT to occur
True
Which of the following are true for ‘RR’ year designation?
- 68 means 1968
- 25 means 2025
- 50 can either mean 1950 or 2050
- 45 means 2045
- 68 means 1968
- 25 means 2025
- 45 means 2045
Note: For years 0 - 49, it will refer to 2000 - 2049.
For 50 - 99, it will refer to 1950 - 1999.
The data type that would be used for a column that will be storing employee photographs for a large, multi-national company is:
- CLOB
- BLOB
- NCLOB
- GLOB
-BLOB
Which of the following are valid table names that may be used with the CREATE TABLE command? choose all that apply
- $Customers
- Order_lines
- “Boat Inventory”
- Retired#Emps
-Financial_Categories_No_longer_active
- Order_lines
- “Boat Inventory”
- Retired#Emps
A collection of the database objects, such as tables, sequences, views, and indexes, that are owned by a single user account is called a(n) _____.
- Role
- database partition
- ERD
- schema
schema
What DDL command permits you to add, modify, or drop a column or constraint for an existing table?
- ADD
- DROP
- MODIFY
- ALTER
- ALTER
What component of SQL is used to build and manage the database objects and define the structure of the database?
- DML
- DLD
- the schema
- DDL
- DDL
Oracle naming conventions
- Must begin with a letter
- Can be 1-30 characters long
- Must contain only A-Z, a-z, 0-9, _, $, #
- Must not duplicate name of another object owned by the same user
- Must not be an oracle reserved word
Quoted names are allowed (but not reccommended)
True
- Quoted names are case sensitive and you must use the quotes after
What is BLOB (Binary Large Object )?
binary data, such as an image or video
What is CLOB (Char Large Object )?
character data
- ASC11 code
What is NCLOB?
CLOB for unicode
What are two ways to create constraints for a table?
- at table creation time
- after the table is created, with an ALTER table command
Constraint naming convention
Table_column_constraint_type
What happens after you set a column as UNUSED?
- The column and its data are still within the table’s storage and it is no longer available and can never be recovered, but it is not dropped
- The column still counts against the total column limit (1000)
- are not physically dropped, but act as if they were dropped
What happens after you DROP a column?
- The column may or may not contain data
- The column cannot be referenced by a foreign key in another table
- You cannot “un-drop” a column
- All data currently stored in the column to be deleted, in each row of the table, will be permanently deleted
Consider the following statement:
CREATE TABLE PORTS
(port_id NUMBER,
port_name VARCHAR2(20));
Which of the following modifications to the statement is the only valid way to declare that the port_name is required (not optional)?
- port_name VARCHAR2(20) NOT NULL (port_name)
- port_name VARCHAR2(20),
CONSTRAINT ports_port_name_nn NOT NULL (port_name) - port_name VARCHAR2(20) NOT NULL
- ALTER TABLE PORTS
CONSTRAINT ports_port_name_nn NOT NULL (port_name);
- port_name VARCHAR2(20) NOT NULL
What would happen when the following statement is executed:
CREATE TABLE GGC_Student
( StudentID CHAR(6),
SName VarChar2(40),
gpa Number(5,4)
);
- An error will occur because no primary key is specified
- An error will occur because a table name cannot contain an underscore
- The table will be created with StudentID as the Primary Key
- The table will be created without a primary key
- The table will be created without a primary key
