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A Guide to MySQL

2. Objectives Start MySQL and learn how to use the MySQL Reference Manual
Create a database
Change (activate) a database
Create tables using MySQL
Create and run SQL commands in MySQL
A Guide to MySQL

3. Objectives (continued)
Identify and use data types to define columns in tables
Understand and use nulls
Add rows to tables
View table data
Correct errors in a database
A Guide to MySQL

4. Objectives (continued)
Save SQL commands and results to a file
Describe a table’s layout using MySQL
A Guide to MySQL

5. Introduction Structured Query Language (SQL):
Popular and widely used language for retrieving and manipulating database data
Developed in mid-1970s under the name SEQUEL
Renamed SQL in 1980
Used by most DBMSs
A Guide to MySQL

6. Introduction to MySQL Starting MySQL Obtaining help
Accessing the MySQL Reference Manual
A Guide to MySQL

7. Starting MySQL Windows XP
Click Start button
Point to All Programs
Point to MySQL on menu
Point to MySQL Server 4.1
Click MySQL Command Line Client
Must enter password in Command Line Client window
A Guide to MySQL

8. Obtaining Help in MySQL
Type \h at MySQL> prompt
Type “help” followed by name of command
help contents
help union
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9. A Guide to MySQL

10. Using MySQL Reference Manual to Get Help
Click MySQL Manual - Table of Contents on MySQL 4.1 submenu
Can access online
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11. A Guide to MySQL

12. Creating a Database Must create a database before creating tables
Use CREATE DATABASE command
Include database name
A Guide to MySQL

13. Creating a Database (continued)
A Guide to MySQL

14. Changing the Default Database
Default database: database to which all subsequent commands pertain
USE command, followed by database name:
Changes the default database
Execute at the start of every session
A Guide to MySQL

15. Creating a Table Describe the layout of each table in the database
Use CREATE TABLE command
TABLE is followed by the table name
Follow this with the names and data types of the columns in the table
Data types define type and size of data
A Guide to MySQL

16. Table and Column Name Restrictions
Names cannot exceed 18 characters
Must start with a letter
Can contain letters, numbers, and underscores (_)
Cannot contain spaces
A Guide to MySQL

17. Creating the REP Table
A Guide to MySQL

18. Entering Commands in MySQL
Commands are free-format; no rules stating specific words in specific positions
Press ENTER to move to the next line in a command
Indicate the end of a command by typing a semicolon
Commands are not case sensitive
A Guide to MySQL

19. Running SQL Commands
A Guide to MySQL

20. Editing SQL Commands
Statement history: stores most recently used command
Editing commands:
Use arrow keys to move up, down, left, and right
Use Ctrl+A to move to beginning of line
Use Ctrl+E to move to end of line
Use Backspace and Delete keys
A Guide to MySQL

21. Errors in SQL Commands
A Guide to MySQL

22. Editing MySQL Commands
Press Up arrow key to go to top line
Press Enter key to move to next line if line is correct
Use Right and Left arrow keys to move to location of error
Press ENTER key when line is correct
If Enter is not pressed on a line, line not part of the revised command
A Guide to MySQL

23. Dropping a Table
Can correct errors by dropping (deleting) a table and starting over
Useful when table is created before errors are discovered
Command is followed by the table to be dropped and a semicolon
Any data in table also deleted
A Guide to MySQL

24. Data Types For each table column, type of data must be defined
Common data types:
CHAR(n)
VARCHAR(n)
DATE
DECIMAL(p,q)
INT
SMALLINT
A Guide to MySQL

25. Nulls
A special value to represent situation when actual value is not known for a column
Can specify whether to allow nulls in the individual columns
Should not allow nulls for primary key columns
A Guide to MySQL

26. Implementation of Nulls
Use NOT NULL clause in CREATE TABLE command to exclude the use of nulls in a column
Default is to allow null values
If a column is defined as NOT NULL, system will reject any attempt to store a null value there
A Guide to MySQL

27. Adding Rows to a Table INSERT command:
INSERT INTO followed by table name
VALUES command followed by specific values in parentheses
Values for character columns in single quotation marks
A Guide to MySQL

28. The Insert Command
A Guide to MySQL

29. Modifying the INSERT Command
To add new rows modify previous INSERT command
Use same editing techniques as those used to correct errors
A Guide to MySQL

30. Adding Additional Rows
A Guide to MySQL

31. The INSERT Command with Nulls
Use a special format of INSERT command to enter a null value in a table
Identify the names of the columns that accept non- null values, then list only the non-null values after the VALUES command
A Guide to MySQL

32. The INSERT Command with Nulls
Enter only non-null values
Precisely indicate values you are entering by listing the columns
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33. The INSERT Command with Nulls (continued)
A Guide to MySQL

34. Viewing Table Data
Use SELECT command to display all the rows and columns in a table
SELECT * FROM followed by the name of the table
Ends with a semicolon
A Guide to MySQL

35. Viewing Table Data (continued)
A Guide to MySQL

36. Viewing Table Data (continued)
A Guide to MySQL

37. Correcting Errors In the Database
UPDATE command is used to update a value in a table
DELETE command allows you to delete a record
INSERT command allows you to add a record
A Guide to MySQL

38. Correcting Errors in the Database
UPDATE: change the value in a table
DELETE: delete a row from a table
A Guide to MySQL

39. Correcting Errors in the Database (continued)
A Guide to MySQL

40. Correcting Errors in the Database (continued)
A Guide to MySQL

41. Saving SQL Commands Allows you to use commands again without retyping
Different methods for each SQL implementation you are using
Oracle SQL*Plus and SQL*Plus Worksheet use a script file
Access saves queries as objects
MySQL uses an editor to save text files
A Guide to MySQL

42. Saving SQL Commands Script file: File containing SQL commands
Use a text editor or word processor to create
Save with a .txt file name extension
Run in MySQL:
SOURCE file name
\. file name
Include full path if file is in folder other than default
A Guide to MySQL

43. Creating the Remaining Database Tables
Execute appropriate CREATE TABLE and INSERT commands
Save these commands to a secondary storage device
A Guide to MySQL

44. Describing a Table
A Guide to MySQL

45. Summary Use MySQL Command Line Client window to enter commands
Type \h or help to obtain help at the mysql> prompt
Use MySQL Reference Manual for more detailed help
A Guide to MySQL

46. Summary (continued)
Use the CREATE DATABASE command to create a database
Use the USE command to change the default database
Use the CREATE TABLE command to create tables
Use the DROP TABLE command to delete a table
A Guide to MySQL

47. Summary (continued)
CHAR, VARCHAR, DATE, DECIMAL, INT and SMALLINT data types
Use INSERT command to add rows
Use NOT Null clause to identify columns that cannot have a null value
Use SELECT command to view data in a table
A Guide to MySQL

48. Summary (continued) Use UPDATE command to change the value in a column
Use DELETE command to delete a row
Use SHOW COLUMNS command to display a table’s structure
A Guide to MySQL