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PANGKALAN DATA

PANGKALAN DATA. KONSEP PANGKALAN DATA. Data Vs Maklumat – Data : merupakan fakta mentah mengenai sesuatu perkara dan belum diproses • Eg:harga barang, markah pelajar – Maklumat :merupakan hasil daripada data yang telah diproses yang mempunyai makna dan berguna kepada pengguna.

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PANGKALAN DATA

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  1. PANGKALAN DATA

  2. KONSEP PANGKALAN DATA • Data Vs Maklumat – Data : merupakan fakta mentah mengenai sesuatu perkara dan belum diproses • Eg:harga barang, markah pelajar – Maklumat :merupakan hasil daripada data yang telah diproses yang mempunyai makna dan berguna kepada pengguna. • Eg:perbandingan harga mengikut tempat :Prestasi pelajar

  3. • Bagaimana komputer menyimpan data – Bermula dari unit terkecil hingga yang terbesar dalam pangkalandata iaitu: • Bit – byte – medan/field – rekod – fail – pangkalan data.

  4. MEDAN KEKUNCI • Untuk memudahkan pencarian maklumat dalam pangkalan data, maka dalam setiap rekod yang disimpan akan mempunyai satu medan yang dikenali sebagai medan kekunci • Medan kekunci menyimpan data yang unik untuk setiap rekod seperti no matrik, no I/C.

  5. KAEDAH PEMPROSESAN • Pemprosesan Kelompok – Urusniaga dikumpul mengikut masa (jam,hari,minggu) kemudian diproses serentak – Con: bil kad kredit • Pemprosesan Masa Nyata – Data diproses pada masa yang sama urusniaga berlaku – Con: ATM kad

  6. ORGANISASI FAIL DLM DBASE 3 jenis kaedah penyimpanan iaitu: – Jujukan • rekod disimpan satu persatu dalam susunan menaik atau menurun. Digunakan dalam medium penyimpanan pita magnetik. • Kebaikan murah • Kelemahan capaian ambil masa yang lama

  7. – Terus • rekod disimpan secara tersusun mengikut medan kekunci, dalam cakera magnet. Kebaikan cepat tetapi kos tinggi – Jujukan terindeks • rekod disimpan secara jujukan dengan indeks untuk capaian hampir terus dalam storan cakera magnet. Sesuai utk uruskan kelompok urutan yg besar & selalu dikemaskini

  8. Masalah Penyimpanan Sistem berorientasikan Fail • Data Redundancy - the same data might be stored in different places • Poor Data Control - redundant data might be slightly different such as in the case when Ms. Jones changes her name to Mrs. Johnson and the change is only reflected in some of the files containing her data • Inability to Easily Manipulate Data - it was a tedious and error prone activity to modify files by hand • Cryptic Work Flows - accessing the data could take excessive programming effort and was too difficult for real-users (as opposed to programmers).

  9. KEPERLUAN KPD P. DATA • Perkongsian – pengguna boleh berkongsi data antara satu dengan lain con: antara jabatan • Keselamatan – Capaian boleh dihadkan pada pihak yang tertentu sahaja • Elak pertindanan data – Berbilang fail dan data yang sama dapat dielakkan • Integriti data – Perubahan dalam satu-satu fail dapat dikemaskini secara serentak.

  10. Pangkalan Data • Himpunan data-data berkaitan yang dikongsi bersama oleh pelbagai kategori pengguna, bagi memenuhi kehendak dan keperluan maklumat sesebuah organisasi

  11. Pengurusan Pangkalan Data • DBMS merupakan perisian utk membina, mengubah & mencapai maklumat dalam pangkalan data. • DBMS • Membina pelbagai fail pangkalan data. • Menambah dan mengubah data dalam fail. • Menyusun rekod • Mengenal pasti lokasi data dengan tepat.

  12. Terdiri daripada: – Kamus data- menerangkan struktur p. data – Bahasa pertanyaan- utk capai maklumat & bahasa yang digunakan secara meluas ialah SQL iaitu bahasa pertanyaan berstruktur

  13. Perisian Popular • Microsoft Access • dBASE III Plus • FoxBASE Plus • Oracle • MS SQL Server • SoftBASE • Clipper • Paradox

  14. Pangkalan Data

  15. Pangkalan Data

  16. Atribut Nama Rekod Atribut Nilai Pangkalan Data Persekitaran : Perpustakaan Fail: Buku

  17. Jenis-Jenis Database • Analytic Database • are primarily static, read-only databases which store archived, historical data used for analysis. For example, a company might store sales records over the last ten years in an analytic database and use that database to analyze marketing strategies in relationship to demographics.

  18. Operational Database • are used to manage more dynamic bits of data. These types of databases allow you to do more than simply view archived data. Operational databases allow you to modify that data (add, change or delete data). • For example, a company might have an operational database used to track warehouse/stock quantities.

  19. Jenis Organisasi/ susunan DBMS(Model) • Pangkalan Data Hierarki – Rekod distruktur dlm nod. Setiap permulaan ada satu nod ibu dan ibu boleh ada bbrp nod anak – Sebuah rekod dipecahkan kpd bbrp segmen yg berhubungan dlm bentuk cabang pokok yang terbalik dikenali sebagai hubungan satu kpd banyak @ ibu & anak

  20. Pangkalan data rangkaian (network database) • The network model is very similar to the hierarchical model actually. In fact, the hierarchical model is a subset of the network model. However, instead of using a single-parent tree hierarchy, the network model uses set theory to provide a tree-like hierarchy with the exception that child tables were allowed to have more than one parent. This allowed the network model to support many-to-many relationships.

  21. Visually, a Network Database looks like a hierarchical Database in that you can see it as a type of tree. However, in the case of a Network Database, the look is more like several trees which share branches. Thus, children can have multiple parents and parents can have multiple children.

  22. Relational Database • At the core of the relational model is the concept of a table (also called a relation) in which all data is stored. Each table is made up of records (horizontal rows also known as tuples) and fields (vertical columns also known as attributes). • It is important to note that how or where the tables of data are stored makes no difference. Each table can be identified by a unique name and that name can be used by the database to find the table behind the scenes. As a user, all you need to know is the table name in order to use it. You do not need to worry about the complexities of how the data is stored on the hard drive.

  23. This is quite a bit different from the hierarchical and network models in which the user had to have an understanding of how the data was structured within the database in order to retrieve, insert, update, or delete records from the database.

  24. Client/Server database • A client/server database works like this: A database server is left running 24 hours a day, and 7 days a week. Thus, the server can handle database requests at any hour. Database requests come in from "clients" who access the database through its command line interface or by connecting to a database socket. Requests are handled as they come in and multiple requests can be handled at one time.

  25. PENGGUNAAN STRATEGIK P.DATA • GUDANG DATA – Menyimpan maklumat dlman & luaran , lama & baru organisasi bagi membantu dalam perancangan & pembuatan keputusan organisasi – Kaedah utk pencarian maklumat dalam gudang data dikenali sebagai perlombongan data. – Terdapat pelbagai jenis pangkalan data utk perniagaan iaitu: • Direktori perniagaan, data demografi, p. data teks & pangkalan data internet.

  26. PENGURUSAN P.DATA • PENTADBIR PANGKALAN DATA – Ialah pakar yang membina & menguruskan pangkalan data dan menentukan hak pemprosesan iaitu siapa yang berhak utk capaian terhadap jenis data yang tertentu.

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