namayana

Database definition:

· stored data nest in magnetic disk, optical disk or another secondary storage

· inwrought collection from data’s mutual related from a enterprise (companies, government resort or private)

· manufacturing business -> production planning data, recent production data, materials order data, etc

· hospital -> patient data, doctor, nurse, etc

DATABASE MANAGEMENT SYSTEM definition

Database collection/federation with application software based on database

These application programs are used to accessing and take care of database

Principal purpose DBMS prepares a easy environment and efficient for use, withdrawal and data storage and information

BIT, BYTE, FIELD

Bit is a be smallest data part value containing 0 or 1

Byte collection from beets of a kind

Field nest byte of a kind, in data base is used attribute term

NIM	NAMA	ALAMAT
9455500001	ABDULLAH	BENDA RAYA NO 4
9455500002	AMINAH	CILEDUG TENGAH NO 4
9455500003	BUDIMAN	HALIMUN NO 7

Attribute/field

Be character or characteristics from a entities that prepare to prepare detail explanation about entities

A also can has attribute

Attribute example:

Student University: nim, name, address

Car: nomor_plat, color, kind, cc

Attribute types

Single vs. multi value

Single is only can loaded at most one value

Multi value can loaded with interest from one value with same type

Atomic vs. composition

Atomic an indiscrete into attribute smaller

Composition be federation from several attributes smaller

Derived attribute

Attribute the value can be produced from attribute value other, example; age that produced from date attribute born

Null value attribute

Attribute doesn't has value to a record

Mandatory value attribute

Attribute that must has value

RECORD/TUPLE

Be a data line in a customer

Consist of where is attributes mutual connected to information entities /customer in its entirety

Entities/ file

File is collection from record of a kind and has element same, attribute same but vary data value.

File type

In application processing, file can category as follows:

-Main file

-Transaction file

-Report file

-History file

-Patron file

-Work file

Domain

Domain is collection from values that permitted to stay in one or more attribute. Every attribute in a data base relational defined as a domain

Key element record that worn to find record when does access or can also be used to identify every entity/record/line.

Key kinds

· Super key be one or more attribute from a table that can be used to identify entity/record from table uniquely (not all attributes be super key)

· Candidate key a super key with minimal attribute. Candidate key can not full attribute from other table so that candidate key beyond question super key but not yet sure on the contrary.

· Primary key One of the attribute from candidate key can be choose/determined to be primary key with three criteria’s as follows:

1. Key more natural to be used as reference

2. Key simpler

3. Key well guaranteed the uniqueness

· Alternate key attribute from candidate key not chosen be primary key.

· Foreign key be just any attribute that indicate to primary key in other table. Foreign key will happen at one particular customer that has cardinalities one to many (one to many) or many to many (many to many). Foreign key usually always put in table that aims too many.

· External key be a lexical attribute (or collection lexical attribute) the values always identify one object instance.

ERD a network model that use wording that kept in system according to abstract.

between difference DFD and ERD

DFD will be a function network model that be carried out by system

ERD be data network model that emphasized in structure and relationship data

ERD elements

Entity

In ER diagram entity described with long square form. Entity something that there in real system also where does stored data or where found data.

Relationship

In ER diagram relationship can be described with a lozenge. relationship natural connection that between entities. in general given name with verb base so that make easy to do the customer reading.

Relationship degree

Total entities that participate in one relationship. degree often worn in ERD.

Attribute

Character or characteristics from every entities also relationship

Kardinalitas

Show optimum tupel that can elations with entities in entities other

Unary relationship

Model relationship that between entities that come from entity set same.

Binary relationship

Model relationship between those 2 entities.

Nary relationship

Be relationship between instances from 3 type’s entities unilaterally.

Found 3 cardinalities customer that is

One to one: connection level one to one declared with one incident in entities first, has only one connection with one incident in entities second and on the contrary.

one to many or many to one: connection level one to many equal to many to one depending from which direction connection seen. to one incident in entities first can has many connections with incident in entities second, if on the contrary one incident in entities second only can has connection with one incident in entities first.

many to many: happen if every incident in a entities has many connections with incident in entities another.