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What does DDL stand for?
• Data Definition Language
Valid or invalid? INVALID
CREATE TABLE p_order_line
(
ORDER_NUM char(5) NOT NULL PRIMARY KEY,
PART_NUM char(4) NOT NULL PRIMARY KEY,
NUM_ORDERED decimal(3,0) NULL,
QUOTED_PRICE decimal(6,2) NULL
)
The MySQL DBMS requires a concatenated primary key to be specified at the end of the
table definition
CREATE TABLE p_order_line
(
ORDER_NUM char(5) NOT NULL,
PART_NUM char(4) NOT NULL,
NUM_ORDERED decimal(3,0) NULL,
QUOTED_PRICE decimal(6,2) NULL,
PRIMARY KEY (ORDER_NUM,PART_NUM)
)
Valid or Invalid? INVALID
H_BOOK
Field
BOOK_CODE
TITLE
PUBLISHER_CODE
TYPE
PRICE
PAPERBACK
Type
char(4)
char(40)
char(3)
char(3)
decimal(4,2)
char(1)
Null
NO
YES
YES
YES
YES
YES
Key
PRI
Default Extra
insert into H_BOOK
values ('32AB', 'The Audacity of Hope', 'ABY')
If you do not specify the columns you are inserting data into SQL expects there to be a
value for each column that exists in the table
insert into H_BOOK
(BOOK_CODE, TITLE, PUBLISHER_CODE)
values ('32AB', 'The Audacity of Hope', 'ABY')
Which clause changes the
characteristics of an existing column?
• MODIFY clause of ALTER TABLE
command changes characteristics of existing
columns
What does SQL stand for?
• Structured Query Language
What does DBMS stand for?
• Database Management System
Name an example of a DBMS besides
MySQL
•
•
•
•
Oracle
Microsoft SQL Server
Access
DB2
What are some benefits of views?
What is a database?
• Database: structure containing categories of
information and relationships between these
categories
10
Normalization
• minimize duplication of data
• help safeguard against data anomalies
• improve performance for certain activities
11
What is the name of this type of
notation
Crow’s Foot Notation
12
Coalesce()
• Returns the first non-NULL value in the list, or
NULL if there are no non-NULL values.
Example:
select
coalesce(null, null, 'Kris')
Student_Names
Student_Phones
select
sn.first_name,
sn.last_name,
coalesce(busn.phone_number, cell.phone_number, home.phone_number) as "phone"
from
student_names sn
left outer join
student_phones home on
home.student_id = sn.student_id and
home.phone_type = 'home'
left outer join
student_phones cell on
cell.student_id = sn.student_id and
cell.phone_type = 'cell'
left outer join
student_phones busn on
busn.student_id = sn.student_id and
busn.phone_type = 'busn'
Results
Oracle Platform Note
• In MySQL and Microsoft SQL Server it is
possible to write/run a query that does not
reference a table
Example:
select
'kris'
Oracle Platform Note
• In Oracle the query must reference a table. We
can use the “dummy” table DUAL, which is
provided in Oracle, as our referenced table.
Example:
select
'kris‘
From
Dual
SQL Challenge #1
• Return a list of just city names from the table
Locations
• Note: the format of all values in the Locations
table is as follows: City, State abbreviation
– hints
• left()
• locate()
• http://dev.mysql.com/doc/refman/5.5/en/
SQL Challenge #1
select
left(city_state, locate(',', city_state) - 1)
from
locations
SQL Challenge #2
• Return a distinct list of first & last names of
boat owners who pay a rental fee that is less
than the maximum paid rental fee and greater
than the minimum rental fee paid
– Hints
• Use a select statement
• 2 subqueries
SQL Challenge #2
select distinct
first_name,
last_name
from
a_owner o
join
a_marina_slip ms on
ms.owner_num = o.owner_num and
ms.rental_fee < (select max(rental_fee) from a_marina_slip) and
ms.rental_fee > (select min(rental_fee) from a_marina_slip)
SQL Challenge #2
select distinct
first_name,
last_name
from
a_owner o
join
a_marina_slip ms on
ms.owner_num = o.owner_num
where
ms.rental_fee < (select max(rental_fee) from a_marina_slip) and
ms.rental_fee > (select min(rental_fee) from a_marina_slip)
SQL Challenge #3
• Alexamara is considering applying the following
discounts to it’s rental fees
– rental fee > 3000 gets a 10% discount
– rental fee > 2000 & < 3000 gets a 5% discount
– all other rental fees receive no discount
• Before applying the discounts they want to know
how much money each marina would bring in
prior to the discount and after the discount
• Write a single query that will show them the
before discount total and after discount total by
marina name
SQL Challenge #3
• Hints
– query will be returning 2 different sums
– can place a case statement within a sum()
function
– in phpmyadmin the opening parenthesis needs to
be on same line as the word sum
SQL Challenge #3
• Pseudocode
select
name,
sum(non-discounted rental fees),
sum(discounted rental fees)
from
marina slip
join
marina on matching marina nums
group by
name
SQL Challenge #3
• Pseudocode
select
name,
sum(non-discounted rental fees),
sum(discounted rental fees)
from
marina slip
join
marina on matching marina nums
group by
name
case statement
goes here
SQL Challenge #3
select
name,
sum(rental_fee) as 'before',
sum(
case
when rental_fee > 3000
then rental_fee * .9
when rental_fee > 2000
then rental_fee * .95
else
rental_fee
end) as 'after'
from
a_marina_slip ms
join
a_marina m on
m.marina_num = ms.marina_num
group by
name
User Defined Stored Procedures and
Functions
• Sometimes referred to as routines
• Created by users
• Not to be confused with system procedures
and functions
– DBMS has its own set of procedures/functions
used to manage the database
Procedures/functions are similar to
procedures/functions in other programming languages
in that they can:
• Utilize input and output parameters
• Call other procedures and functions.
• Allow for modular programming
Example Function
delimiter //
create function calculate_annual_salary
(
weekly_hrs decimal(10,2),
pay_rt decimal(10,2)
)
returns decimal(16,2)
begin
declare
annual_salary decimal(16,2);
set annual_salary = weekly_hrs * pay_rt * 52;
return annual_salary;
end
What will the following query return?
select
calculate_annual_salary(40.0, 10.00) as 'annual salary'
Function Definition
delimiter //
create function calculate_annual_salary
(
weekly_hrs decimal(10,2),
pay_rt decimal(10,2)
)
returns decimal(16,2)
begin
declare
annual_salary decimal(16,2);
set annual_salary = weekly_hrs * pay_rt * 52;
return annual_salary;
end
Results
annual salary
20800.00
What will the following query return?
select
calculate_annual_salary(40.0, 20.00) as 'annual salary'
Function Definition
delimiter //
create function calculate_annual_salary
(
weekly_hrs decimal(10,2),
pay_rt decimal(10,2)
)
returns decimal(16,2)
begin
declare
annual_salary decimal(16,2);
set annual_salary = weekly_hrs * pay_rt * 52;
return annual_salary;
end
Results
annual salary
41600.00
System Catalog
• Set of database objects (tables, views,
procedures, etc.) used by the DBMS to store
and utilize information about databases
• Contains metadata
– metadata is data about data
• System catalog contains very useful
information
select
concat('select * from ', TABLE_NAME)
from
INFORMATION_SCHEMA.TABLES
order by
table_schema desc,
table_name
What is Dynamic SQL?
• SQL statements constructed at runtime and
passed to the database management system
for execution; generating SQL statements on
the fly
• Can be useful
• Can make you very vulnerable to security
threats if not used properly