PERTEMUAN 9 SISTEM BASIS DATA Presented by : Sity Aisyah Nasution, M.Kom Email : dryesha@gmail.com Blog : yeshasalsabila.blogspot.com

PENERAPAN NORMALISASI Teknik Normalisasi Merupakan proses pengelompokan data elemen menadi tabel yang menunjukkan entitas dan relasinya. Pada proses normalisasi selalu diuji pada beberapa kondisi, apakah ada kesulitan pada saat menambah, menghapus, mengubah dan membaca data pada suatu database. Teaching Tips It may be useful to walk through this diagram in class. The textbook coverage included numbered annotations that highlight portions of this diagram. Remind students that any given information system may include many instances of each of these IS application processes and databases.

Tujuan dari normalisasi data adalah agar menghasilkan : Struktur record yang konsisten secara logic Struktur record yang mudah dimengerti Struktur record yang sederhana dalam pemeliharaan Struktur record yang mudah ditampilkan kembali Meminimalkan kerangkapan data guna meningkatkan kinerja sistem. Teaching Tips It may be useful to walk through this diagram in class. The textbook coverage included numbered annotations that highlight portions of this diagram. Remind students that any given information system may include many instances of each of these IS application processes and databases.

Contoh penerapan normalisasi : Berikut ini adalah contoh dokumen mengenai faktur pembelian barang pada PT. Abadi Jaya Teaching Tips It may be useful to walk through this diagram in class. The textbook coverage included numbered annotations that highlight portions of this diagram. Remind students that any given information system may include many instances of each of these IS application processes and databases.

Gambar 1.1 Faktur Pembelian Barang Teaching Tips It may be useful to walk through this diagram in class. The textbook coverage included numbered annotations that highlight portions of this diagram. Remind students that any given information system may include many instances of each of these IS application processes and databases. Gambar 1.1 Faktur Pembelian Barang

Bentuk Unnormalisasi Tabel diatas dikatakan tidak normal adalah : Tabel 1.1 Unnormalisasi Tabel diatas dikatakan tidak normal adalah : Jika relasi mempunyai bentuk non flat Data disimpan apa adanya, tidak memiliki struktur file yang sama Jika relasi memuat atribut berulang-ulang (repeating group) Teaching Tips It may be useful to walk through this diagram in class. The textbook coverage included numbered annotations that highlight portions of this diagram. Remind students that any given information system may include many instances of each of these IS application processes and databases.

Bentuk Normal Pertama (1 NF) Tabel 1.2 Normalisasi 1 NF Pada normal 1 NF masih terjadi banyak kelemahan, terutama pada proses ANOMALI insert, update dan delete. Teaching Tips It may be useful to walk through this diagram in class. The textbook coverage included numbered annotations that highlight portions of this diagram. Remind students that any given information system may include many instances of each of these IS application processes and databases.

Penyisipan (Inserting) Pada proses penyisipan tidak dapat memasukkan kode dan nama supplier saja tanpa adanya transaksi pembelian, sehingga supplier baru bisa dimasukkan kalau ada transaksi pembelian. Penghapusan (Deleting) Bila satu record atau baris diatas dihapus, misal nomor faktur 557, maka berakibat pada penghapusan data supplier S02 (Hitachi) padahal data tersebut masih diperlukan. Pengubahan (Updating) Kode dan nama supplier terlihat ditulis berkali-kali, bila nama supplier berubah, maka disetiap baris yang ada harus diubah, bila tidak menjadi tidak konsisten. Permasalahan dalam normal 1 NF : Tidak dapat menyisipkan informasi parsial Terhapusnya informasi ketika menghapus record Pembaharuan atribut bukan kunci mengakibatkan sejumlah record berubah Teaching Tips It may be useful to walk through this diagram in class. The textbook coverage included numbered annotations that highlight portions of this diagram. Remind students that any given information system may include many instances of each of these IS application processes and databases.

Bentuk Normal Kedua (2 NF) Teaching Tips It may be useful to walk through this diagram in class. The textbook coverage included numbered annotations that highlight portions of this diagram. Remind students that any given information system may include many instances of each of these IS application processes and databases. Tabel 1.3 Normalisasi 2 NF

Permasalahan dalam normal 2 NF : Dengan melihat normal pertama, kita dapat mendekomposisikan menjadi 3 tabel beserta kunci primer yaitu Tabel Supplier (Kode_Supplier), Barang (Kode_barang), dan Faktur (No_faktur). Pemecahan tabel diatas, maka untuk pengujian bentuk normal kesatu yaitu : insert, update, dan delete aka terjawab. Kode supplier dan nama supplier baru dapat masuk kapan saja tanpa adanya transakasi pada tabel faktur. Demikian pula untuk proses update dan delete untuk tabel supplier dan barang. Permasalahan dalam normal 2 NF : Atribut quantitas pada tabel faktur, tidak tergantung pada kunci utama, atribut tersebut bergantung fungsi pada kode barang, hal ini dinamakan ketergantungan transitif dan haruslah dipilah menjadi 2 tabel. Masih terdapat pengulangan, yaitu setiap kali satu faktur yang terdiri dari 5 macam barang maka harus 5 kali juga dituliskan No_faktur, tanggal dan jatuh tempo. Teaching Tips It may be useful to walk through this diagram in class. The textbook coverage included numbered annotations that highlight portions of this diagram. Remind students that any given information system may include many instances of each of these IS application processes and databases.

Bentuk Normal Ketiga (3 NF) Teaching Tips It may be useful to walk through this diagram in class. The textbook coverage included numbered annotations that highlight portions of this diagram. Remind students that any given information system may include many instances of each of these IS application processes and databases. Tabel 1.4 Normalisasi 3 NF

Bentuk normal ketiga mempunyai syarat, setiap tabel tidak mempunyai atribut yang bergantung transitif, harus bergantung penuh pada kunci utama dan harus memenuhi bentuk normal kedua (2 NF). Untuk memenuhi bentuk normal ketiga (3 NF), maka pada tabel faktur harus didekomposisi (dipecah) lagi menjadi 2 tabel yaitu ; tabel faktur dan tabel transaksi. Teaching Tips It may be useful to walk through this diagram in class. The textbook coverage included numbered annotations that highlight portions of this diagram. Remind students that any given information system may include many instances of each of these IS application processes and databases.

T U G A S Normalkan bentuk dokumen di bawah ini ! Catatan : Kode jurusan SI : 114 Kode Jurusan TI : 224 Teaching Tips It may be useful to walk through this diagram in class. The textbook coverage included numbered annotations that highlight portions of this diagram. Remind students that any given information system may include many instances of each of these IS application processes and databases.

Teaching Tips It may be useful to walk through this diagram in class. The textbook coverage included numbered annotations that highlight portions of this diagram. Remind students that any given information system may include many instances of each of these IS application processes and databases.

Teaching Tips It may be useful to walk through this diagram in class. The textbook coverage included numbered annotations that highlight portions of this diagram. Remind students that any given information system may include many instances of each of these IS application processes and databases.

Teaching Tips It may be useful to walk through this diagram in class. The textbook coverage included numbered annotations that highlight portions of this diagram. Remind students that any given information system may include many instances of each of these IS application processes and databases.

Sekian Dan ... Teaching Tips It may be useful to walk through this diagram in class. The textbook coverage included numbered annotations that highlight portions of this diagram. Remind students that any given information system may include many instances of each of these IS application processes and databases.