12-CRS-0106 REVISED 8 FEB 2013 Pengantar Basis Data: Basic File System & Konsep Basis Data Tim pengajar BDR Ganjil 2015/2016

12-CRS-0106 REVISED 8 FEB 2013 Agenda Definisi: File Database DBMS File System History of database Advantages of DBMS Definisi: Database DBMS Architecture Database System Components Database System User

12-CRS-0106 REVISED 8 FEB Definisi Field Basic element of data (name, date, etc.) Record  Collection of related fields that we treat as a unit (employee record)  May be of a fixed or variable size File  Collection of similar records  Treated as an entity by applications  Usually referenced by a name  Access controls usually at file level Data  Known facts that can be recorded and have an implicit meaning.

12-CRS-0106 REVISED 8 FEB 2013 Is this file system ? ? ?

12-CRS-0106 REVISED 8 FEB Semi otomatis...

12-CRS-0106 REVISED 8 FEB Rada canggih dikit

12-CRS-0106 REVISED 8 FEB 2013 Masih ingat yang ini ?

12-CRS-0106 REVISED 8 FEB Device Drivers Communicate directly with device Basic File System Buffering, placing data on device Basic I/O Supervisor I/O initiation and termination Logical I/O – Deals with records Access method (pile, sequential, hashed, index) Standard interface with the user File System Architecture

12-CRS-0106 REVISED 8 FEB User & program commands Directory management User access control File operations file name File structure Access method File manipulation functions Records File management concerns Blocking Physical blocks in main memory buffers Physical blocks in secondary storage (disk) Disk scheduling I/O File allocation Free storage management Operating system concerns Elements of a File System

12-CRS-0106 REVISED 8 FEB DATA VS INFORMASI

12-CRS-0106 REVISED 8 FEB Database ?

12-CRS-0106 REVISED 8 FEB Mini-world  Some part of the real world about which data is stored in a database. For example, student grades and transcripts at a university. Database  Collection of related data files  Relationships are explicit  Used by a number of applications Definisi

12-CRS-0106 REVISED 8 FEB Essential database characteristics: Represents an aspect of the real world (miniworld), Well structured (even has a strict regular structure), Reflects (or should reflect) current state Has users and applications, Stored in a permanent (persistent) computer memory, and Accessed and manipulated using a DBMS All these characteristics have to be met

12-CRS-0106 REVISED 8 FEB Real World facts about the world in a database more facts some more rather long facts about the world in the databse facts about the world in a database Database Facts about world and behaviour of world represented in contents and operations of a database Users Ilustrasi Database

12-CRS-0106 REVISED 8 FEB DBMS Database Management System (DBMS)  A software package/ system to facilitate the creation and maintenance of a computerized database. Database System  The DBMS software together with the data itself. Sometimes, the applications are also included. Database Management System (DBMS) provides…. … efficient, reliable, convenient, and safe multi-user storage of and access to massive amounts of persistent data.

12-CRS-0106 REVISED 8 FEB Application Programs/ Interactive Queries Catalog Database Query Processor Data Access DBMS Database System Users/ Programmers Database Description DDL Compiler DBA A simplified database system layout

12-CRS-0106 REVISED 8 FEB History of Database

12-CRS-0106 REVISED 8 FEB Navigational DBMS

12-CRS-0106 REVISED 8 FEB Example of hierarchial DB

12-CRS-0106 REVISED 8 FEB Relational DBMS

12-CRS-0106 REVISED 8 FEB Advantage of Database System? Tugas anda adalah untuk mencari keuntungan dari implementasi DBMS

12-CRS-0106 REVISED 8 FEB Database System Components

12-CRS-0106 REVISED 8 FEB

12-CRS-0106 REVISED 8 FEB Data Models A collection of tools for describing – data – data relationships – data semantics – data constraints Entity-Relationship model Relational model

12-CRS-0106 REVISED 8 FEB Contoh ER Model

12-CRS-0106 REVISED 8 FEB Contoh Relational Model customer- name Customer-id customer- street customer- city account- number Johnson Smith Johnson Jones Smith Alma North Alma Main North Palo Alto Rye Palo Alto Harrison Rye A-101 A-215 A-201 A-217 A-201 Attributes

12-CRS-0106 REVISED 8 FEB Level of Abstractions

12-CRS-0106 REVISED 8 FEB Levels of Abstraction Physical level: describes how a record (e.g., customer) is stored. Logical level: describes data stored in database, and the relationships among the data. type customer = record customer_id : string; customer_name : string; customer_street : string; customer_city : integer; end; View level: application programs hide details of data types. Views can also hide information (such as an employee’s salary) for security purposes.

12-CRS-0106 REVISED 8 FEB taken from Stanford online class, 2011

12-CRS-0106 REVISED 8 FEB Databases Everywhere!!! DBMS contains information about a particular enterprise – Collection of interrelated data – Set of programs to access the data – An environment that is both convenient and efficient to use Database Applications: – Banking: all transactions – Airlines: reservations, schedules – Universities: registration, grades – Sales: customers, products, purchases – Online retailers: order tracking, customized recommendations – Manufacturing: production, inventory, orders, supply chain – Human resources: employee records, salaries, tax deductions Databases touch all aspects of our lives

12-CRS-0106 REVISED 8 FEB taken from Stanford online class, 2011

12-CRS-0106 REVISED 8 FEB Review

12-CRS-0106 REVISED 8 FEB