[CO] Database System (English ver.)

What’s Database?

Database is a unit of records which connect each other and draw itself. Database is used to ease a processing data and change data with accurately. The goal of database itself is to help people searching data.

Database system component:

 

Explanations:

1. Database applications: a set or more computer programs which have function as a connector for user and DBMS.
2. DBMS: Database Management System, program to process database.
3. SQL (read: see-quel): Structure Query Language, is a sub language data connector between database applications and DBMS.

Functions and contents of applications programs:

• Database Applications
  • Create and process forms.
  • Create and transmit queries.
  • Create and process reports.
  • Execute application logic.
  • Control application.
• DBMS
  • Create database.
  • Create table.
  • Create supporting and structures.
  • Read database data.
  • Update database data.
  • Maintain database structures.
  • Enforce rules.
  • Control concurrency.
  • Provide security.
  • Perform backup and recovery.

Read and update database perform with a process like this: DBMS receive SQL and request along with transform request becoming database action.

In database contain referential integrity constraints which have purpose to do a constraint if form doesn’t fill with a right way.

• Database
  • User data.
  • Metadata.
  • Indexes and related structures.
  • Stored procedures.
  • Triggers.
  • Application metadata.

Metadata are data of database structure. For examples: name of tables, columns and tables name where both of them included, property from tables and columns.

Stored procedures are program which stored in database. Examples: to backup or remove data if data have age more than 1 year.

Triggers are procedures which used when data have a certain activity.

What’s characteristic and kind of database?

Characteristic and kind of database divided into 3 parts:

1. Personal.
   • User: 1
   • Size: less than 10 Mb
   • Example: used at home industry such as a house painting, etc.
2. Workgroup.
   • User: less than 25
   • Size: less than 100 Mb
   • Example: in a business, from manager computer center to computer in branch industry. Used LAN (Local Area Network) to connect each computer.
3. Organization.
   • User: hundred to thousand users.
   • Size: more than 1 quintillion byte, many database.
   • Example: SIM and STNK registrations. From center nation office to offices in many regions.

Process to make database contains 3 phase, Requirement, Design, and Implementation.

No.	Phase	Database	Application
1.	Requirement	- Build up data model. - Determine item data. - Define rules and limits.	- Determine application requirement.
2.	Design	- Table. - Relation. - Limits. - Stored procedures and triggers.	- Forms. - Reports. - Queries. - Application code.
3.	Implementation	- Create table. - Create relation. - Create limit. - Write stored procedures and triggers.  - Fill database. - Examine.	- Create forms. - Create reports. - Create queries. - Write application code. - Examine.

How is Database history?

Database history can explain like this:

1. x - 1986: Data saved in a list and characteristic. Processing data required by general using of magnetic ribbon media.
2. 1986 – 1980: Hierarchies, example: DL/ I (Data Language One) which is named IMS (DBMS IBM) and Network Model such as IDMS (DBMS network).
3. 1980: SQL become relational standard language.
4. 1982: first DBMS microcomputer, such as dBase, R:Base, Paradox.
5. 1985: DBMS which object oriented (OODBMS).
6. 1991: discovered Microsoft Ships Access.
7. 1995: Database internet first application.
8. 1997: Determining XML in database processing.

Model of Data Entity-Relationship.

Database scheme divided into 3 parts, external scheme, conceptual scheme, and internal scheme. External scheme is a half of database scheme. Conceptual scheme is a whole logic view. Internal scheme is a physic scheme which is storage by a product or certain technique.

Model of Entity-Relationship is a concept set and graphic symbol which is used to create conceptual scheme.

Model Extended E-R or E-R has many unsure such as entity, attribute, and relationship.

1. Entity: a thing which can identify within user environment. Entity divided into entity class and entity instance.
   • Entity class: a unit of entity and drew by structure or entity format in its class.
   • Entity instance from entity class: representation of that entity. Example: COSTUMER class has many instances of customer.
2. Attribute: is a characteristic of this entity. Attribute contain of multi value and composite. Example: CUSTOMER has attribute ContactName, Address, Street, City, Province, etc. ContactName is a multi value attribute and Address, City, Province is a composite attribute.
3. Relationship: is a relationship of each entity. For example relation of binary. 3 binary relation are 1:1 (one to one), 1:N (one to many), N:M (many to many).

Entity contains weak entity and strong entity. Weak entity is an entity which can’t exist in a database without the second entity. And strong entity is a entity which can exist without the second entity.

Untuk Indonesia ver. klik disini.

Source:

M. Kroenke, David. Database Processing (Dasar-dasar, Desain, Implementasi) Jilid 1 Edisi 9. 2005. Jakarta : Erlangga

Author:

Vania Wahyu (12.02.0054)

Game Technology, Unika Soegijapranata Semarang.

As a assignment of Computer Organization first semester.