1. The University of Akron College of Applied Science & Technology Dept
The University of Akron College of Applied Science & Technology Dept. of Business & Information Technology
2440: 141 Web Site Administration
Database Management Using SQL
Instructor: Joseph Nattey

2. Database Concepts A database is a collection of data about entities
For example, a database might contain checking account information in a bank, product items information in an on-line store, students’ records in a college, and so on
Relational databases store information in simple structures called tables
Most commercial databases today are relational databases
Introduction to SQL

3. Database Concepts
An entity is a distinct object, for example, a person's name, a product, or an event, to be presented in the table
The columns in the table contain fields
A field contains a single, specific piece of information within a record. So, a record is a group of related fields
The data in a table is organized into rows and columns
The rows in the table are called records
A record contains information about a given entity
Introduction to SQL

4. Sample Item Database Table
Item Number
Item Name
Unit Price
Inventory
100
Camera
$267.99 13
101
Washer
$489.56 8
102 TV
$189.99 29
Introduction to SQL

5. Creating Tables Details required to create database tables include:
Table name
The table name identifies the table
A database can consist of many tables
You use the name of a table to reference the table and to manipulate data in that table
Fields names
Field data types
Introduction to SQL

6. Data Types Data type Sample data Description CHAR(length)
Newcastle Dr.
For nonnumeric data. Fixed length
VARCHAR(length)
For nonnumeric data. Variable length (listed length indicates maximum)
INTEGER
123456
For whole number data between –231 and
SMALLINT 31
For whole number data between –215 and
NUMERIC
2.6E+10
Very large or vary small numbers
DATE
11/16/2014
For date. Implementations vary in different databases
Introduction to SQL

7. Primary Key
An integrity constraint that uses a unique identifier to uniquely identify a record in a table
Introduction to SQL

8. Using Common Fields (Foreign Keys) to Link Two Tables
productID
productName
model
Price
manufacturerID
100
Washer D1
356.99 1
200 TV S2
255.68 2
manufacturerID
name
address
phone 1
Weiwei Co.
Edward Rd
123456 2
XYZ Co.
Central
654321
Introduction to SQL

9. An Introduction to SQL
The Structured Query Language (SQL) is a language embedded in relational DBMSs to process relational databases
SQL can be used as a:
Data definition language (DDL):
Used to define a table’s column, add or delete columns, and delete unneeded tables
Example: Create table, alter table, drop table, etc
Data manipulation language(DML):
Used to insert, update, delete, and retrieve data in a table
Example: Insert into, update, delete, and select
Introduction to SQL

10. Creating and Dropping Tables
CREATE TABLE tableName (field1 dataType, field2 dataType, …) (field1 dataType PRIMARY KEY, field2 dataType, …) DROP TABLE tableName
Introduction to SQL

11. Example: Student Table
CREATE TABLE student ( id integer PRIMARY KEY, firstName varchar(15), lastName varchar(15));
Introduction to SQL

12. Inserting Data Into a Table
INSERT INTO TABLE tableName VALUES (value1, value2, …) or INSERT INTO TABLE tableName (field1, field2, …) VALUES ( value1, value2, …)
Introduction to SQL

13. Updating Table Data
UPDATE tableName SET field1=value1, fiedl2=value2, … WHERE conditions
The WHERE clause gives the condition for selecting which rows (records) are to be updated in the table identified as tableName
The SET keyword is followed by the field list to be updated
If the WHERE clause is omitted, all rows in the table are updated
Introduction to SQL

14. Updating Table Data
Conditions in a WHERE clause are similar to conditional statements in JSP
Conditions can be constructed with comparison operators and logical operators
You can use the six comparison operators ( =, <> for not equal, <, >, <=, >=) as well as the three logical operators (AND, OR, and NOT) to create compound conditions or to negate a condition
Introduction to SQL

15. Deleting Records from a Table
DELETE FROM tableName WHERE conditions
This deletes all rows that satisfy the WHERE clause in the statement
If there is no WHERE clause, then all rows in the table are deleted
Introduction to SQL

16. Retrieving Data
SELECT field1, field2, …
FROM tableName
WHERE conditions
The SELECT clause lists the fields retrieved in the query result, separated by commas
The FROM clause lists one or more table names to be used by the query
All fields listed in the SELECT or WHERE clauses must be found in one and only one of the tables listed in the FROM clause
Introduction to SQL

17. Retrieving Data…
The WHERE clause contains conditions for selecting rows from the tables listed in the FROM clause
The data retrieved are from the rows that satisfy the condition (and are therefore selected)
If the WHERE clause is omitted, all rows are selected
Introduction to SQL

18. Retrieving Data… Introduction to SQL CREATE TABLE STATION
(ID INTEGER PRIMARY KEY,
CITY CHAR(20),
STATE CHAR(2),
LAT_N REAL,
LONG_W REAL);
populate the table STATION with a few rows:
INSERT INTO STATION VALUES (13, 'Phoenix', 'AZ', 33, 112);
INSERT INTO STATION VALUES (44, 'Denver', 'CO', 40, 105);
INSERT INTO STATION VALUES (66, 'Caribou', 'ME', 47, 68);
query to look at table STATION in undefined order:
SELECT * FROM STATION;
ID CITY STATE LAT_N LONG_W
13 Phoenix AZ
44 Denver CO
66 Caribou ME 47 68
query to select Northern stations (Northern latitude > 39.7):
SELECT * FROM STATION
WHERE LAT_N > 39.7;
Introduction to SQL

19. Wildcard Characters
Special symbols that represent any character or combination of characters
Make it easier to use inexact spelling in a query
The percent symbol % represents any collection of characters, including zero characters
The underscore _ represents any individual character
Introduction to SQL

20. Wildcard Characters
Get all employee details who’s names starts with M.
SELECT * FROM DEPT FROM EMPLOYEE WHERE EMPNAME LIKE 'M%‘
Result:
Introduction to SQL

21. Wildcard Characters Using the SQL _ Wildcard Example
The following SQL statement selects all customers with a City starting with any character, followed by "erlin":
Example
SELECT * FROM Customers WHERE City LIKE '_erlin';
Introduction to SQL

22. Sorting Retrieved Data
It is possible to control the order in which rows are returned in a result set by using the ORDER BY clause.
The ORDER BY clause specifies one or more columns on which the sort is based.
Each column used for sorting can be ordered in ascending or descending order by using the ASC or DESC keywords, respectively. 
Introduction to SQL

23. Sorting Retrieved Data
SELECT field1, field2, … FROM tableName WHERE conditions
ORDER BY sort_field1 DESC, sort_field2, …
Sort data retrieved in a particular order
Introduction to SQL

24. Sorting Retrieved Data
SELECT LASTNAME, FIRSTNME, EMPNO
FROM EMPLOYEES
WHERE EMPNO > '000200'
ORDER BY LASTNAME ASC, FIRSTNME ASC
LASTNAME FIRSTNME EMPNO GOUNOT JASON JEFFERSON JAMES JOHNSON SYBIL JONES WILLIAM LEE WING LUTZ JENNIFER MARINO SALVATORE MEHTA RAMLAL PARKER JOHN PEREZ MARIA SCHNEIDER ETHEL SETRIGHT MAUDE SMITH DANIEL SMITH PHILIP record(s) selected.
Introduction to SQL

25. Steps to Accessing Databases
Load the database driver
Define the connection URL
Establish the connection
Create the statement object
Execute a query or update
Process the results
Close the connection
Introduction to SQL