Learning MySQL with PHP - I

1. Learning PHP-MySQL
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By: Akash Gupta

2. Course Contents
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• Basics of Database
• MySQL
• PHP basics
• HTML/Javascript/CSS basics
• Creating a simple Registration form using
html/php/javascript/css/mysql
• More practicals…
• Project

3. Scopes of the Course
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After completion of this course, you will:
• Learn PHP and MySQL
• Learn HTML, Javascript and CSS
• Create a Webpage
• Create a Industry-level project

4. What is Database?
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A database is a separate application that stores a collection of data.
Each database has one or more distinct APIs for creating, accessing,
managing, searching, and replicating the data it holds.
Other kinds of data stores can be used, such as files on the file system or
large hash tables in memory but data fetching and writing would not be
so fast and easy with those type of systems.
So now a days we use relational database management systems
(RDBMS) to store and manager huge volume of data. This is called
relational database because all the data is stored into different tables and
relations are established using primary keys or other keys known as
foreign keys.
A Relational DataBase Management System (RDBMS) is a software
that:
• Enables you to implement a database with tables, columns, and
indexes.
• Guarantees the Referential Integrity between rows of various tables.
• Updates the indexes automatically.
• Interprets an SQL query and combines information from various tables.

5. RDBMS Terminology
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Before we proceed to explain MySQL database system, lets
revise few definitions related to database.
Database: A database is a collection of tables, with related
data.
Table: A table is a matrix with data. A table in a database
looks like a simple spreadsheet.
Column: One column (data element) contains data of one and
the same kind, for example the column postcode.
Row: A row (= tuple, entry or record) is a group of related
data, for example the data of one subscription.
Redundancy: Storing data twice, redundantly to make the
system faster.

6. aadhayan academy of education
RDBMS Terminology cont.
Primary Key: A primary key is unique. A key value can
not occur twice in one table. With a key you can find at
most one row.
Foreign Key: A foreign key is the linking pin between two
tables.
Compound Key: A compound key (composite key) is a
key that consists of multiple columns, because one
column is not sufficiently unique.
Index: An index in a database resembles an index at the
back of a book.
Referential Integrity: Referential Integrity makes sure
that a foreign key value always points to an existing row.

7. An example…
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Student_ID Name Major Grade
101 Shannon BCB A
102 Mike BBMB A
103 Wang MCDB A
… … …

8. MySQL Introduction
 MySQL is a fast, easy-to-use RDBMS used being
used for many small and big businesses. MySQL is
developed, marketed, and supported by MySQL AB,
which is a Swedish company. MySQL is becoming so
popular because of many good reasons.
 MySQL is released under an open-source license. So
you have nothing to pay to use it.
 MySQL works on many operating systems and with
many languages including PHP, PERL, C, C++, JAVA
etc.
 MySQL is very friendly to PHP, the most appreciated
language for web development.
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9. Basic MySQL Operations
 Create table
 Insert records
 Load data
 Retrieve records
 Update records
 Delete records
 Modify table
 Join table
 Drop table
 Optimize table
 Count, Like, Order by, Group by
 More advanced ones (sub-queries, stored procedures, triggers, views
…)
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10. How MySQL stores data (by
default)
 A MySQL server can store several databases
 Databases are stored as directories
 Default is at /usr/local/mysql/var/
 Tables are stored as files inside each database
(directory)
 For each table, it has three files:
 table.FRM file containing information about the table
structure
 table.MYD file containing the row data
 table.MYI containing any indexes belonging with this
table, as well as some statistics about the table.aadhayan academy of education

11. Login
 mysql –h hostname –u username –p [password]
 Example
% mysql -u usrname -p
Enter password: passowrd
Welcome to the MySQL monitor. Commands end with ; or g.
Your MySQL connection id is 23 to server version: 3.23.41.
Type 'help;' or 'h' for help. Type 'c' to clear the buffer.
mysql>
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12. Create User and Database
 mysql>use mysql;
 Use database mysql, used by the system
 mysql>insert into user (Host, User,
Password) values (‘localhost’, ‘test1’,
password(‘pass1’));
 Create a new database user test1
 An alternative

GRANT USAGE ON *.* TO ‘test1’@’localhost‘
IDENTIFIED BY ‘pass1’;
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13. Create User and Database (cont.)
 mysql>insert into db (Host, Db, User, Select_priv,
Insert_priv, Update_priv, Delete_priv, Create_priv,
Drop_priv) values (‘localhost’, ‘testdb’, ‘test1‘, ‘Y’, ‘Y’, ‘Y’,
‘Y’, ‘Y’, ‘Y’);
 Create a new database testdb for user test1
 mysql>flush privileges
 Reloads the privileges from the grant tables in the
database mysql
 An alternative
 GRANT SELECT, INSERT, UPDATE, DELETE, CREATE,
DROP ON testdb.* TO ‘test1’@’localhost’ IDENTIFIED
BY ‘pass1’;
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14. What are the current databases at the server?
mysql> show databases;
+--------------+
| Database |
+--------------+
| mysql | mysql is a database (stores users’ password …) used by system.
| test |
+--------------+
Create a database (make a directory) whose name is MyDB
mysql> create database MyDB;
Select database to use
mysql> use MyDB;
Database changed
What tables are currently stored in the MyDB database?
mysql> show tables;
Empty set (0.00 sec)
Create Database
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15.  CREATE TABLE Table_Name (column_specifications)
 Example
mysql> CREATE TABLE student
-> (
-> student_ID INT UNSIGNED NOT NULL,
-> name VARCHAR(20) NOT NULL,
-> major VARCHAR(50),
-> grade VARCHAR(5)
-> );
Query OK, 0 rows affected (0.00 sec)
Student_ID Name Major Grade
Create Table
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16. Display Table Structure
mysql> show tables;
+--------------------+
| Tables_in_MyDB |
+--------------------+
| student |
+--------------------+
1 row in set (0.00 sec)
mysql> describe student;
+---------------+----------------------+------+------+----------+--------+
| Field | Type | Null | Key | Default | Extra |
+---------------+----------------------+-------+-----+-----------+-------+
| student_ID | int(10) unsigned | | | 0 | |
| name | varchar(20) | | | | |
| major | varchar(50) | YES | | NULL | |
| grade | varchar(5) | YES | | NULL | |
+---------------+----------------------+-------+------+----------+-------+
4 rows in set (0.00 sec)
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17. Modify Table Structure
 ALTER TABLE table_name Operations
mysql> alter table student add primary key (student_ID);
Query OK, 0 rows affected (0.00 sec)
Records: 0 Duplicates: 0 Warnings: 0
mysql> describe student;
+---------------+--------------------- +-------+------+----------+-------+
| Field | Type | Null | Key | Default | Extra |
+---------------+----------------------+-------+------+----------+-------+
| student_ID | int(10) unsigned | | PRI | 0 | |
| name | varchar(20) | | | | |
| major | varchar(10) | YES | | NULL | |
| grade | varchar(5) | YES | | NULL | |
+---------------+----------------------+-------+------+-----------+-------+
4 rows in set (0.00 sec)
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18. Insert Record
 INSERT INTO table_name SET col_name1=value1,
col_name2=value2, col_name3=value3, …
 Example
mysql> INSERT INTO student SET student_ID=101, name='Shannon', major='BCB',
grade='A';
Query OK, 1 row affected (0.00 sec)
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Student_ID Name Major Grade
101 Shannon BCB A

19. Retrieve Record
 SELECT what_columns
FROM table or tables
WHERE condition
 Example
mysql> SELECT major, grade FROM student
WHERE name='Shannon';
+-------+-------+
| major| grade|
+-------+-------+
| BCB | A |
+-------+-------+
1 row in set (0.00 sec)
mysql> SELECT * FROM student;
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Student_ID Name Major Grade
101 Shannon BCB A
102 Mike BBMB A
103 Wang MCDB A
… … …

20. Update Record
 UPDATE table_name
SET which columns to change
WHERE condition
 Example
mysql> UPDATE student SET grade='B' WHERE name='Shannon';
Query OK, 1 row affected (0.00 sec)
Rows matched: 1 Changed: 1 Warnings: 0
mysql> SELECT * FROM student WHERE name=‘Shannon’;
+------------+---------------+--------+--------+
| name | student_ID | major | grade |
+------------+---------------+--------+--------+
| Shannon | 101 | BCB | B |
+------------+---------------+--------+--------+
1 row in set (0.00 sec)
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21. Delete Record
 DELETE FROM table_name WHERE condition
 Example
mysql> DELETE FROM student WHERE name='Shannon';
Query OK, 1 row affected (0.00 sec)
Mysql> DELETE FROM student;
Will delete ALL student records!
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22. Drop Table
 DROP TABLE table_name
 Example
mysql> drop table student;
Query OK, 0 rows affected (0.00 sec)
 Logout MySQL
mysq> quit;
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23. More Table Retrieval
 OR
mysql> select name from student where major = 'BCB' OR major = 'CS';
 COUNT (Count query results)
mysql> select count(name) from student where major = 'BCB' OR major = 'CS';
 ORDER BY (Sort query results)
mysql> select name from student where major = 'BCB' OR major = 'CS‘ ORDER
BY name;
mysql> select name from student where major = 'BCB' OR major = 'CS‘ ORDER
BY name DESC;
mysql> select * from student where major = 'BCB' OR major = 'CS‘ ORDER BY
student_id ASC, name DESC
 LIKE (Pattern matching)
mysql> select name from student where name LIKE "J%";
 DISTINCT (Remove duplicates)
mysql> select major from student;
mysql> select DISTINCT major from student;
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24. Group By
 Cluster query results based on different groups
 Example
mysql> select major, count(*) from student GROUP BY major;
+---------+----------+
| major | count(*) |
+---------+----------+
| BBMB | 3 |
| BCB | 3 |
| Chem | 1 |
| CS | 5 |
| IG | 2 |
| Math | 2 |
| MCDB | 3 |
| Stat | 2 |
+---------+------------+
8 rows in set (0.00 sec)
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25. NULL
 No Value
 Can not use the usual comparison operators (>, =, != …)
 Use IS or IS NOT operators to compare with
 Example
mysql> select name from student where project_ID = NULL;
Empty set (0.00 sec)
mysql> select name from student where project_ID IS NULL;
+-------+
| name|
+-------+
| Jerry |
+-------+
1 row in set (0.00 sec)
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26. Table Join
 Retrieve information from multiple tables
 Example
 Which BCB students chose level-4 project?
mysql> select s.name from student s, project p
where s.project_ID = p.project_ID
and s.major='BCB' and p.level=4;
+------------+
| name |
+------------+
| Stephen |
+------------+
1 row in set (0.00 sec)
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27. MySQL Optimization
 Index
 Index columns that you search for
 Example
mysql> alter table student add index (name);
Query OK, 22 rows affected (0.00 sec)
Records: 22 Duplicates: 0 Warnings: 0
mysql> describe student;
+---------------+----------------------+--------+-------+---------+---------+
| Field | Type | Null | Key | Default | Extra |
+---------------+----------------------+--------+-------+---------+---------+
| student_ID | int(10) unsigned | | PRI | 0 | |
| name | varchar(20) | | MUL | | |
| major | varchar(10) | YES | | NULL | |
| project_ID | int(10) unsigned | YES | | NULL | |
+--------------+-----------------------+--------+-------+---------+---------+
4 rows in set (0.00 sec)
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28. MySQL Optimization (cont.)
 EXPLAIN
 Find what is going on a slow query
 Example

mysql> EXPLAIN select * from student s, project p
where s.project_ID = p.project_ID order by p.level;
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