This document discusses CRUD operations in MySQL and database design. It explains that tables contain records made of columns/fields that classify data. Common data types like varchar, char, int, float, datetime are described. CRUD stands for Create, Read, Update, Delete - the basic functions to add, retrieve, modify and remove data in a database. Examples of SQL queries like SELECT, INSERT, UPDATE, DELETE are provided to demonstrate CRUD operations on a sample Users table. Additional SQL clauses like WHERE, BETWEEN, IN, LIKE, GROUP BY, COUNT, SUM are also overviewed.

1. CRUD in MySql
By: Aimal Miakhel

2. Think of each table as a spreadsheet
We define columns, also known as fields,
which classify our data
Each record in the table is a row

3. Varchar
◦ Variable Characters, specify up to how many
characters something will be
Char
◦ A set number of characters, good for things like
state abbreviations
Int
◦ Whole numbers, positive or negative

4. Float
◦ Floating Point, also known as a decimal
Text
◦ A huge blob of text, like a paragraph or more
TinyInt / Bit / Boolean
◦ 0 or 1, True or False
DateTime
◦ A date and time 0000-00-00 00:00:00

5. Depending on the flavor of SQL (Oracle,
MySQL, MSSQL, PostgreSQL, etc) there are
many more
Don’t get overwhelmed, just think of what
will be best in terms of sorting and lookups

6. Creating Table in Mysql
CREATE TABLE User
(
ID int,
Username varchar(255),
Password varchar(255)
);

7. Username
◦ Varchar
Password
◦ Varchar
ID
◦ Integer
AccountCreated
◦ DateTime

8. ID UserNa
me
Passwo
rd
1 John 123
2 Jane 334
3 Sally 567
4 Ryan 8675
5 Joe 90887
9
User _Table

9. Create
Read
Update
Delete

10. INSERT is used to create a new record in the
database
For example user is a table
INSERT into user VALUES (1,‘Aimal’,
‘Miakhel’);

11. SELECT is used to retrieve a record in the
database
To select all the records from user table
SELECT * FROM user;

12. Where is used for condition for some specific
groups or records it filters the selection
Eg.
SELECT username, password FROM users
WHERE ID = 1

13. UPDATE is used to change record(s) in the
database
UPDATE users SET username = ‘Ahmad’
WHERE ID = 1
Or
UPDATE users SET username = ‘Ahmad’
WHERE username = ‘Aimal’

14. DELETE is used to remove records from the
database
DELETE FROM users WHERE ID = 1
** if you do not specify anything in the WHERE
clause, it will delete everything in that table

15. SELECT User FROM Users WHERE ID IN (1,2)
SELECT * FROM User
WHERE Name IN (‘Ahmad',‘Ali');

16. SELECT User FROM Users WHERE ID BETWEEN
3 AND 5
SELECT * FROM User
WHERE ID BETWEEN 3 AND 5;

17. WHERE can also use wildcards for text
◦ WHERE Column IS LIKE ‘%something%’
WHERE can use more than =
◦ WHERE ID < 4
◦ WHERE ID <= 4
WHERE can combine conditions
◦ WHERE Column = ‘A’ AND Column2 = ‘B’
◦ WHERE Column = ‘A’ OR Column2 = ‘B’
◦ WHERE (Column = ‘A’ OR Column2 = B’) AND Other
= ‘C’

18. SQL has functions, like COUNT and SUM
SELECT Customer, SUM(Amount) FROM
Orders GROUP BY Customer
SELECT COUNT(Customer) FROM Orders
GROUP BY Customer

19. Design a database for university students
Contains
Student registration
Attendance
Fees
Etc
Date-03-09-2014