1. Structured Query Language
SELECT
WHERE
INSERT
DELETE
Structured Query Language
MySQL~PHP
Anita Philipp – Spring 2010

2. Objectives Study the basics of databases and MySQL
Work with MySQL databases
Define database tables
Modify user privileges
Work with database records
Work with phpMyAdmin

3. Introduction to Databases
Ordered collection of information
Can quickly access information
Each row in a database table is called a record
Record
Single complete set of related information - Row
Fields
Columns in a database table
Individual categories of information stored in a record

4. Introduction to Databases
Flat-File Database
Stores information in a single table
Relational Database
Stores information across multiple related tables

5. Understanding Relational Databases
Primary Table
main table in a relationship that is referenced by another table
Related Table (or “child table”)
references a primary table in a relational database
Primary Key
field that contains a unique identifier for each record in a primary table
Foreign Key
field in a related table that refers to primary key in primary table
link records across multiple tables

6. One-to-One Relationships
Related table - one record for each record in the primary table
Breaks information into multiple, logical sets
Could be placed within a single table
Make one table confidential and accessible only by certain individuals

7. One-to-Many Relationship
one record in a primary table has many related records in a related table
Normalization
multiple related tables to reduce redundant and duplicate information

8. One-to-Many Relationship
Figure 7-3 Table with Redundant Information
Figure 7-4 One-to-Many Relationship

9. Many-to-Many Relationship
Junction Table
Sometimes called “cross-reference” table
Creates a one-to-many relationship for each of the two tables in a many-to-many relationship
Compound key: employee_id and language_id
Number of years each programmer has worked with each language
Figure 7-5
Many-to-Many Relationship

10. Working with Database Management Systems
DataBase Management System (DBMS)
Application or collection of applications used to access and manage a database
Schema
Structure of a database including its tables, fields, and relationships
Flat-File Database Management System
Stores data in a flat-file format (text file, one record per line)
Sometimes refers to a one table database
Relational DataBase Management System (RDBMS)
Stores data in a relational format

11. Working with DBMS Query
Structured set of instructions and criteria for retrieving, adding, modifying, and deleting
Structured Query Language (SQL)
Data manipulation language
Open DataBase Connectivity (ODBC)
Allows ODBC-compliant applications to access any data source for which there is an ODBC driver

12. SQL-Structured Query Language
Most widely used language for defining and manipulating relational databases
1. Create new databases
2. Add/modify tables
3. Search for Data
4. Build new tables from existing ones
5. Remove tables and data

13. SQL Language Data Definition Language (DDL)
…defining databases, tables, indexes
Data Manipulation Language (DML)
…searching, retrieving, modifying, inserting,
deleting, updating table data

14. Data Manipulation Language
SQL
Data Manipulation Language
Parameter Declarations
…optional parameters that can be passed to the query
Manipulative Statement
…Indicates the type of action to be taken
(INSERT, DELETE, SELECT, or UPDATE)
Options
…Conditions for selecting record, grouping, ordering,
totaling of records
(FROM, WHERE, GROUP BY, HAVING, ORDER BY
Aggregate Functions
…process multiple record maybe (subset of entire table)
(AVG, COUNT, SUM, MAX, MIN)

15. Two Types of Statements
SQL
Two Types of Statements
Selection Query
Retrieves one or more rows
Action Query
Actions such as update, delete
Does not retrieve any rows

16. Selection Queries

17. Selection Query - Format

18. Retrieving Data – SELECT Statement
SELECT Field FROM TableName
Display the price
SELECT fldPrice FROM tblCars;
Display year and model
SELECT fldYear, fldModel FROM tblCars;
Display all car information
SELECT * FROM tblCars;
*Fields are retrieved in the
order they are in the SELECT
Statement
tblCars
fldMake
fldModel
fldYear
fldColor
fldPrice

19. Sorting Data – ODER BY Statement
SELECT Field FROM TableName ORDER BY Field [ASC | DESC]
Display the Model and Price … least expensive to most expensive
SELECT fldModel, fldPrice FROM tblCars ORDER BY fldPrice;
Display the Price and Model* … most expensive to least expensive
SELECT fldPrice, fldModel FROM tblCars ORDER BY fldPrice DESC;
Display all information sorting by Make in ascending order and Price in descending order
SELECT * FROM tblCars ORDER BY fldMake, fldPrice DESC;
*Fields are retrieved in the
order they are in the SELECT
Statement
tblCars
fldMake
fldModel
fldYear
fldColor
fldPrice

20. Restricting Data – WHERE Statement
SELECT Field FROM TableName WHERE Criteria
< <= > >= = <> IN BETWEEN LIKE NOT
WHERE fldPrice > 2000
WHERE fldPrice BETWEEN 5000 AND (Includes 5000 and 10000)
WHERE fldYear = (If type is Year ~ no quotes needed)
WHERE fldDates> ‘ ’ (If type is Date ~ enclose in single quotes)
WHERE fldModel LIKE ‘E%’ (String enclosed in single quotes LIKE is used for pattern matching)

21. Restricting Data – WHERE Statement
LIKE - Pattern-matching Operator
% Matches multiple characters _ Matches a single character
WHERE fldModel LIKE ‘H%’; …Honda, Hyundai
WHERE fldMake LIKE ‘H_ _ _ _’ ; …Honda
WHERE fldMake = ‘O\’Hara’; If apostrophe is in the name (O’Hara), a backslash is required

22. Restricting Data – WHERE Statement
SELECT Field FROM TableName WHERE Criteria
Display the Model and Price … cars over SELECT fldModel, fldPrice FROM tblCars WHERE fldPrice > 10000; Display the Year and Model… cars made in 2010 SELECT fldYear, fldModel FROM tblCars WHERE fldYear = 2010; Display all information for cars whose Model begins with S SELECT * FROM tblCars WHERE fldModel LIKE ‘S%’;
tblCars
fldMake
fldModel
fldYear
fldColor
fldPrice

23. Restricting Data - DISTINCT
Shows only unique fields, avoids redundancy
SELECT DISTINCT Field FROM TableName
List the makes of cars, do not include name more than once
SELECT DISTINCT fldMake FROM tblCars;
RESULTS: With DISTINCT: Honda, Hyundai Without DISTINCT: Honda, Hyundai, Honda
tblCars
fldMake
fldModel
fldYear
fldColor
fldPrice

24. Restricting Data - LIMIT
Limits the number of records returned
SELECT Field FROM TableName LIMIT StartValue, NumRows;
SELECT fldMake FROM tblCars LIMIT 0, 2; RESULTS: Start with the first record and display 2 records
tblCars
fldMake
fldModel
fldYear
fldColor
fldPrice

25. Action Queries

26. Action Queries Insert, Change, Delete Records Does not retrieve a row
Performs operations on data
Returns a value indicating that operation was successfully completed

27. Action Query -INSERT Insert 2007, Red, and 10000
INSERT INTO Table(Fld1, Fld2, Fld3) VALUES (Val1, Val2, Val3)
Insert 2007, Red, and 10000
INSERT INTO tblCars (fldYear, fldColor, fldPrice) VALUES (2007, ‘Red’, 10000)
*If the field was defined as date type as opposed to year type, the format would be ‘ ’.
tblCars
fldYear
fldColor
fldPrice

28. Action Query - DELETE
DELETE FROM Table WHERE Criteria; DELETE * FROM Table WHERE Criteria;
Delete all cars made prior to 2010
DELETE FROM tblCars WHERE fldYear < 2010
Delete all black cars
DELETE FROM tblCars WHERE fldColor = ‘Black’;
tblCars
fldYear
fldColor
fldPrice

29. Action Query- UPDATE UPDATE Table
SET fld1= NewValue, fld2=NewValue, etc. WHERE Criteria;
Increase the cost of all cars by 10%
UPDATE tblCars SET fldPrice = fldPrice * 1.10;
Change the color of all red cars to maroon UPDATE tblCars SET fldColor = ‘maroon’ WHERE fldcolor = ‘red’ ;
tblCars
fldMake
fldModel
fldYear
fldColor
fldPrice

30. Variables in Queries $carMake = $_POST[“car_make"]; Display Make
$SQLQuery = “SELECT fldMake
FROM tblCars
WHERE fldMake= ‘$carMake’ ”;
FROM tblCars WHERE fldMake= ‘$_POST[“car_make"]’ ”;
Insert a new record into the table
$SQLQuery =
“INSERT INTO tblCars (fldMake, fldModel, fldYear, fldColor, fldPrice) VALUES (‘$carMake’, ‘$carModel’, ‘$carYear’, ‘$carColor’, ‘$carPrice’)”;
tblCars
fldMake
fldModel
fldYear
fldColor
fldPrice

31. Primary Keys: Auto Increment
If the Primary key is an auto-incremented field, use NULL for the insert value
$SQLQuery =
“INSERT INTO tblCars (fldID, fldMake, fldModel, fldYear, fldColor, fldPrice) VALUES (NULL,‘$carMake’, ‘$carModel’, ‘$carYear’, ‘$carColor’, ‘$carPrice’)”;
tblCars
fldID
fldMake
fldModel
fldYear
fldColor
fldPrice

32. The End