1. DATA BASE ADMINISTRING DATABASE SERVICES IN RED HAT LINUX

2. DATA BASE TYPES MySQL PostgreSQL

3. Responsibilities of a DBA 1. Installing & maintaining database servers Installing patches Upgrading softwares 2. Installing & maintaining database clients Installing & maintaining client programs 3. Maintaining accounts and users. Adding /deleting users from the database 4. Ensuring Database security Access control permissions 5. Ensuring data integrity Protects data changes and avoids duplication in multiple users

4. FORMS OF DATABASE 1. Flat Files Simple text files having Space Tab Other characters Example: /etc/passwd 2. Relations The are also called RDBMS Example: Spreadsheets

5. FLAT FILES LIMITATIONS/ DISADVANTAGES 1. Do not scale well Cannot perform random access on data Search line by line (only sequential access) 2. Unsuitable for multi user environments. Simultaneous changes by two users can lead to overwriting

6. RDBMS ADVANTAGES Very good at finding relationships between data Stores data in tables with fields which makes searching and sorting data easy.

7. SQL BASICS Database language Very similar to English and so it’s very simple SQL statements have a defined structure End users are unaware of it

8. CREATING A TABLE IDEA Different column types for data Special column types e.g DATE, VAR, VARCHAR etc.. SQL commands are not case sensitive Whitespace is generally ignored SQL statement terminates with a semi colon (;)

9. CREATING A TABLE. 1 CREATE TABLE phonebook (Last_name VARCHAR (25) NOT NULL, First_name VARCHAR (25) NOT NULL, Phone INT (20) NOT NULL);

10. INSERTING VALUES INSERT INTO phonebook VALUES (‘Doe’, ‘John’, ‘555-555-1212’);

11. TABLE VIEW Last_nameFirst_namePhone DoeJohn555-555-1212 DoeJane555-666-1313 PawlJohn123-456-7890 JohnsonRichard111-222-3333 phonebook

12. DISPLAYING DATA SELECT * FROM phonebook; SELECT first_name FROM phonebook; SELECT Last_name, Phone FROM phonebook; SELECT CONCAT(First_name, “ ”, Last_name) AS Name FROM phonebook; Name John Doe Jane Doe John Pawl Richard Johnson

13. DISPLAYING DATA SELECT * FROM phonebook WHERE first_name= “John”; OPPOSITE SELECT * FROM phonebook WHERE first_name!= “John”;

14. CHOOSING A DATABASE: MySQL V PostgreSQL SPEED: MySQL is faster as compare to PostgreSQL. Queries are executed and results are displayed faster Data Locking: PostgreSQL is better then MySQL MySQL locks the whole table when some one is accessing a single field where as PostgreSQL just locks the raw which is currently being accessed, the rest whole table is open and unlock.

15. Locking table in MySQL and PostgreSQL PostgreSQL Last_nameFirst_namePhone DoeJohn555-555-1212 DoeJane555-666-1313 PawlJohn123-456-7890 JohnsonRichard111-222-3333

16. PostgreSQL IS ACID COMPLIANCE Atomicity: If you have a power failure or server crash after an original record has been deleted but before the updated one has been added, you done lose the record because atomic transaction ensure that the original record is not deleted unless and untill the new record is added. new record to be added(before crash) Record recovered Deleted old record before crash

17. PostgreSQL IS ACID COMPLIANCE Consistency: Incomplete transactions are rolled back to maintain consistency. Isolation: Ensures that multiple transactions operating on the same data are completely isolated from each other. Prevents data corruption if two users try to write to the same record. (locking ) Durability: If server crashed the database examines the log file and makes the changes accordingly.

18. Procedural Languages or imperative language PostgreSQL, C++, JAVA, SQL Programming Languages PHP, Pearl, Visual Basic

19. Installing and configuring MySQL Two ways for installing and configuring 1- Source Version 2- Binary RPM (MySQL-server and MySQL-client) i- Install it by rpm –i command. ii- Initialize the grand tables by mysql_install_db command as root user. iii- Go to mysql environment by typing mysql command. iv- Setting a password for MySQL root user by mysql> SET PASSWORD FOR root = PASSWORD (“secretword”); command inside mysql environment. v- type exit command to exit mysql environment. NOTE: Once installed through RPM, necessary user and group is created automatically by the name MySQL.

20. Creating a database in MySQL mysql> CREATE DATABASE animal; OR mysqladmin –u root –p create animals

21. Granting and Taking away Privileges in MySQL GRANT ALL ON animals.* TO usman IDENTIFIED BY ‘usman123’; REVOKE ALL on animals FROM usman; Database User Database All table User Password

22. Installing and configuring PostgreSQL Two ways for installing and configuring 1- Source Version 2- Binary RPM (postgresql, postgresql-server and postgresql-libs) i- Install it by rpm –i command. ii- Create the data directory by mkdir /usr/local/pgsql command as root user. iii- Then change the user ownership of data directory to postgres user by typing chown postgres /use/local/pgsql command as root user. iv- Then change the group ownership of data directory to postgres group by typing chgrp postgres /use/local/pgsql command as root user. v- Then change your self to a postgres user by the command su- postgres in order to initialize the data directories. vi- To initialize give the command initdb –D /user/local/pgsql/data. vii- Now start the database server by the command /usr/bin/postmaster –D /usr/local/pgsql/data OR /usr/bin/pg_ctl -D /usr/local/pgsql/data –l logfile start viii- At the end issue the command postmaster –D /usr/local/pgsql/data & NOTE: Once installed through RPM, necessary user and group is created automatically by the name postgres.

23. Creating a database in PostgreSQL CREATE DATABASE animal; OR createdb animals

24. Creating a database user in PostgreSQL CREATE USER usman; OR createuser usman

25. Deleting a database user in PostgreSQL DROP USER usman; OR dropuser usman

26. Granting and Taking away Privilages in PostgreSQL GRANT ALL ON animals TO usman ; REVOKE ALL on animals FROM usman; Database User

27. Database clients UserDatabase ClientDatabase Server

28. Database clients model 1 UserDatabase ClientDatabase Server Your local host Remote host

29. Database clients model 2 User Database Client Database Server Your local host Remote host 1 Remote host 2

30. Database clients model 3 User Web Browser Database Client Web Server Database Server Your local host Remote host 1 Remote host 2

31. Changing a database and getting help mysql> help; mysql> use animals; database name