Database Basics

A database is an information organizer. We use many databases in our day-to- day lives. Common databases includes address books, telephone books, and the index in the back of a textbook. These databases contain subject material arranged in an order which helps us in find information that we need quickly and efficiently. The library card catalog is another example of a database. Think of the problems you'd have if you tried to find a particular book in there was no organization in the library!

Before computerized systems, the card catalog contained up to three cards for each book in the library. Books were indexed by title, subject, and author. With computers however, the library has only one entry for each book, saving them time, energy, and money. Now, when you're looking for a book, it's easy to find by title, subject, or author - all available at the touch of a key!

What makes up a database?

The structure of a database is based on fields, records, and files.

Fields - Fields are the smallest unit in a database. Fields contain single pieces of information about "something." Say, for example, we want to create and use a database that contains all of our students' names, addresses, and parents information. Individual pieces of data that we might want to include would be:

Student name

Parent's name

Address

Phone number

Teacher comments

Each of these categories is a field.

Records - Fields make up records. All of the information about one entity (our "something") is a record. Using our student database example, all of the information about one student will be one record. For example:

Robin Jones

Ben & Claire Jones

1234 Camilla Way; St. Cloud, Florida, 12345

904-555-1234

Robin is a good student, but needs to focus and concentrate in school

All of this information about Robin is a record. In other databases, records might include books, inventory items, etc.

Files - The final part of the database structure is the file. All of the records make up the file. In our example, all of our students in the class would comprise the file. In other words, all of the information about an entire group is the file.

Remember these terms:

Fields are individual pieces of information that make up records.

Records are all the information about one entity and make up files.

Files are all the information about one group.

 

Skema suatu Database

Data Base (basis data) merupakan kumpulan data yang saling berhubungan. Hubungan antar data dapat ditunjukan dengan adanya field/kolom kunci dari tiap file/tabel yang ada. Dalam satu file atau table terdapat record-record yang sejenis, sama besar, sama bentuk, yang merupakan satu kumpulan entitas yang seragam. Satu record (umumnya digambarkan sebagai baris data) terdiri dari field yang saling berhubungan menunjukan bahwa field tersebut dalam satu pengertian yang lengkap dan disimpan dalam satu record.

Adapun Struktur Database adalah:

Database

File/Table
Record
Elemen data/Field

Dari pengertian diatas dapat disimpulkan bahwa basis data mempunyai beberapa kriteria penting, yaitu :

1. Bersifat data oriented dan bukan program oriented.
2. Dapat digunakan oleh beberapa program aplikasi tanpa perlu 

     mengubah basis datanya.
3. Dapat dikembangkan dengan mudah, baik volume maupun

     strukturnya.
4. Dapat memenuhi kebutuhan sistem-sistem baru secara mudah
5. Dapat digunakan dengan cara-cara yang berbeda.

Prinsip utama Data Base adalah pengaturan data dengan tujuan utama fleksibelitas dan kecepatan pada saat pengambilan data kembali. Adapun ciri-ciri basis data diantaranya adalah sebagai berikut :
1. Efisiensi meliputi kecepatan, ukuran, dan ketepatan
2. Data dalam jumlah besar.
3. Berbagi Pakai (dipakai bersama sama/Sharebility).
4. Mengurangi bahkan menghilangkan terjadinya duplikasi dan  ketidakkonsistenan data.