Sistem Basis Data -...

Sistem Basis DataPertemuan 2 : Pemodelan Data & Pemilihan Tipe Data

Andronicus Riyono, M.T.

Enterprise Data Model

• The first step in database development, in which the scope and general contents of organizational databases are specified.

• Preliminary Data Model

Entity-Relationship Model Constructs

• Basic Symbols

• Entity

• Attribute

• Relationship

• Relationship degree

• Relationship cardinality

Basic Symbols

Derived Attribute Contoh 1

Derived Attribute Contoh II

Derived Attribute Contoh II

Associative Entity

Relationship degree

Relationship Cardinality

Entity

• Entity: A person, place, object, event, or concept in the user environment about which the organization wishes to maintain data.

• Orang: Pegawai, Mahasiswa, Pasien

• Tempat: Toko, Gudang, Provinsi

• Obyek: Mesin, Gedung, Mobil

• Event: Penjualan, Pendaftaran, Perpanjangan

• Konsep: Matakuliah, Pekerjaan

Entity vs Entity Instance

• Entity type: A collection of entities that share common properties or characteristics.

• Entity instance: A single occurrence of an entity type.

• satu macam entity Pelatihan banyak instances (Pelatihan PHP, Pelatihan Oracle, Pelatihan Web Design, Pelatihan MS Office)

Entity vs Input/Output/User

Entity vsInput/Output/User

Entity = hanya yang perlu dicatat datanya saja

Entity Naming Guidelines

• Kata Benda Tunggal (MAHASISWA, PEGAWAI, MOBIL, EMPLOYEE)

• Spesifik (CUSTOMER or CLIENT)

• Singkat (REGISTRATION vs STUDENT REGISTRATION FOR CLASS)

• Konsisten di seluruh E-R Diagram

Memilih Tipe Data

• Hemat Media Penyimpanan

• Mampu Mewakili Semua Nilai yang Diperlukan

• Menjaga/Memperbaiki Kualitas Data

• Mendukung dan Memudahkan Semua Manipulasi Data yang Diperlukan

MySQL 5 Numeric Data Types

• TINYINT

• SMALLINT

• MEDIUMINT

• INT

• BIGINT

Menyimpan Kode

• Mencatat Teks vs. Tabel Referensi

• Meminimalkan Kesalahan Pengetikan

• Memudahkan Update