make a normalization from ERD picture above....??...
From the picture above,we can see two that confusion can lead to an error occurs :
- No cardinality between PART and PROJECT, and
- Ternary relationship have on the relationship.
ER-Diagram can be improved as below:
ERD is doing so at the mapping tables, we can make all the normalization of the table.
1NF
A table on the form said to be normal 1 if did not reside in the unnormalized form of a table, where there is a kind of field multiplication and field that allows a null (empty). Relations, there is a condition in First Normal Form (1NF) if and only if all domains are covered only atomic value, for example, there is no recurrence group (domains) in a tuple. Advantage of the 1NF relation compared Unnormalized (UNRs) is a simplification in the form of representation and ease of use in developing a query language. Its Insuffiency is the need to duplicate data. Most of the system relations (not all) require a form of relations in 1NF.
2NF
The form of normal 2NF met in a table if it meets the form of 1NF, and all the attributes than the primary key, have a full Functional Dependency on primary key. A table does not meet 2NF, if there are attributes that depended (Functional Dependency) are only partial (only depending on the part of the primary key). If there are attributes that have no dependence on the primary key, then the attributes must be moved or removed
3NF
3NF the changes only at the Pegawai table, Because there is no relation with the primary key that has a non-key attributes of each table above and all tables are considered normal up to 3NF.
·Developing E-R Model pursuant to requirement user / business
·Converting E-R Model to relationship gathering ( tables )
·Relationship normalization to eliminate the anomali
·Implementation to database by making table to every relationship is normalization
Normalization of Data Bases
·Normalization is process of forming of structure of data bases so that most ambiguity can be eliminated.
·Normalization Phase started from lightest phase ( 1NF) tightest till ( 5NF)
·Usually only come up with the storey level 3NF or BCNF of because have adequate enough to yield the tabless which good with quality.
Why is conducted normalization ?
Normalization Conducted bcause :
Optimalisasi Structure of is tables of
Improving speed
Eliminating same data inclusion
More efficient in storage media use
Lessening redundansi
Avoiding anomali ( insertion anomalies, deletion anomalies, update the anomalies).
improved Data integrity
A tables told by goodness ( efisien) or normal if fulfilling 3 criterion :
·If there is decompositionof is tables of, hence decomposition have to be secured ( Lossless-Join Decomposition). Its Meaning, after the tables elaborated / decompositioni become the new tabless, the new tabless can yield the tables from the beginning with is of equal precisely.
·The looking after of functional depending at the (time) of data change ( Dependency Preservation).
·Do not impinge the Normal Boyce-Code of Form ( BCNF)
If third criterion ( BCNF) cannot be fullfiled, hence at least the tables do not impinge the Normal Form of third phase ( 3rd Normal of Form / 3NF).
Functional Dependency
Functional Dependency depict the relation attributes in a relationship
A attribute told by functionally dependant of at other if we use the the attribute value to determine the other attribute value.
Symbol used is to deputize the functional dependency read functionally determine
Symbol used is → to deputize the functional dependency
Notation: A → B
A And B is attribute from a tables. Mean functionally A determine the B or B of depend on A, if and only if there is 2 data line with the same value A, hence assess the B also is of equal
Notation: A∕→ B Or A x→ B
Is reverse from previous notation.
Functional Dependency
Example :
Functional Dependency from tables of value
Nrp → Name
Because to each;every same value Nrp, hence assess the Name also is of equal
{ Mata_Kuliah, NRP } → Value
Because attribut Assess depend on Mata_Kuliah and NRP by together. In other dissimilar meaning for the Mata_Kuliah of same and NRP, hence Assess also is of equal, because Mata_Kuliah and NRP represent the key ( having the character of unique ).
Mata_Kuliah ∕→ NRP
NRP∕→Assess
First Normal Form - 1NF
A tables told to be at the normal form of I of if he do not be at the form of unnormalized table, where happened by the field duplication which of a kind and enable there is field which null ( empty )
Do not can is existence of :
·valuable attribute a lot of ( Multivalued Attribut).
·Composite Attribut or combination from both.
Becoming : Price of Domain attribute have to represent the price atomic
EXAMPLE (1)
Or
• Tabless of is above ineligibility 1NF
EXAMPLE (2)
Tables of student
Tables of Hobby
Second Normal Form - 2NF
Normal form 2NF fullfiled in a tables of if have fulfilled the form 1NF, and all attribute of besides primary key, intactly own the Functional Dependency of at primary key
A tables do not fulfill 2NF, if there is attribute which its depending ( Functional Dependency) only have the character of the just just parsial ( only depend on some of primary key
If there are attribute which do not own the depending to primary key, hence the attribute have to be moved or eliminated
Functional depending of X → Y told by full (of) if vanishing an attribute A from X mean the Y shall no longger hinge functional.
Functional depending of X →Y told by partial of if vanishing a attribute A from X mean the Y still hinge functional.
Scheme of Relationship R in the form of 2NF if every attribute of is non primary key A Î R hinge full (of) by fungsioanl at primary key R.
Tables in the following is fulfilling 1NF, but do not the inclusive of 2NF :
{NIM, KodeMk} → NameMhs
{NIM, KodeMk} → Address
{NIM, KodeMk} → Matakuliah
{NIM, KodeMk} →Sks
{NIM, KodeMk} → LetterValue
The tables require to decomposition become some up to standard tables 2NF
Normal form 3NF fullfiled by if have fulfilled the form 2NF, and otherwise there is attribute of is non primary key owning depending to attribute of[is non primary key the other ( depending transitif).
·So that the tables require to didekomposisi become.:
·Student (NIM, NameMhs, Jalan, KodePos)
KodePos (KodePos, Provinsi, Town)
Boyce-Codd Normal Form (BNCF)
Normal Boyce-Codd of Form have the constraint which is stronger than Normal form third. To become the BNCF, relationship have to in the form of Normal of first and every attribute forced to base on the function of at super attribute of key.
At example of hereunder there are Seminar relationship, Lock the Primary is NPM + Seminar
Student may take one or two seminar. Every seminar require 2 counsellor and every student guided by one of among 2 the seminar counsellor. Every counsellor only may take one just just seminar. at this example of is NPM And Seminar show a Counsellor.
Form the Seminar Relationship is Normal form Third, but do] not BCNF. Because Seminar Code still hinge the function of at Counsellor, if every Counsellor can teach only one seminar. Seminar base on one attribute of non super of key such as those which disayaratakan by BCNF. Hence
Seminar relationship have to be broken to become two that is :
Fifth and fourth Normal form
Relationship in the form of fourth normal ( 4 NF) if relationship in BCNF and tdak contain the depending of a lot of value. To eliminate the depending of a lot of value from one relationship, we divide the relationship become two new relationship. Each relationship contain two attribute having relation of a lot of value. Relationship in the form of fifth normal ( 5NF) dealing by properti is so-called join without existence of information loss ( lossless join). fifth Normal form ( 5 NF is also referred as by PJNF ( normal projection join of form). This case very rare emerge and difficult to be detected practically
- A group of on file data in magnetic disk, optical disk or depository of other sekunder
- Inwrought collection from data which each other is interconnected the than a[n enterprise ( company, governmental institution or private sector)
- Manufacturing business : production planning data, data produce the aktual, data of material ordering, dll
- Hospital : patient data, doctor, nurse, dll
DATABASE MANAGEMENT SYSTEM
Corps / database merger with the application software being based on database
This application program is used to access and look after the database
Especial target of DBMS is provide an efficient and easy environment for the use of, withdrawal and depository of data and information
BEET, BYTE, FIELD
Beet : representing part of containing smallest data assess 0 or 1
Byte : corps from beet which of a kind
Field : a group of byte-byte which of a kind, in data bases used by a attribute term
ATRIBUT/FIELD
Representing the nature of or characteristic from an entitas providing clarification detail of about the entitas
An relationship also can own the attribute
Follow the example of the attribute:
- STUDENT: NIM, NAME, ADDRESS
- CAR: NOMOR_PLAT, COLOUR, TYPE, CC
ATTRIBUTE TYPE
- Single Vs multivalue
Single : only can be filled [by] at most one value
Multivalue: can be filled with interest from one value with the same type
- Atomic Vs composition
Atomic : indiscrete into smaller attribute
Composition : representing merger from some smaller attribute
-Derived Attribute
attribute which its value can be yielded from other dissimilar attribute value,
for example : age yielded from attribute of is date of delivering birth
-Null Value Attribute
Attribute which do not own the value to an record
-Mandatory Value Attribute
Attribute which must own value
RECORD / TUPLE
Representing an data line in an relationship
Consist of by attribute corps of where the attribute interact to inform the entitas / relationship completely
ENTITAS / FILE
File represent the corps from record which of a kind and have the same element, attribute of is of equal but different each other data value.
File Type
In application process :
- Mains File
- Transaction File
- Report File
- History File
- Protector File
- File Work
DOMAIN
Domain represent the corps from values enabled to stay in one or more attribute. Each Every attribute in an bases of data relasional defined by as an domain
LOCK THE DATA ELEMENT
Key is element record weared to find the the record when accessing or can is lso used to identify each every entity / record
TYPE KEY
- Superkey represent one or more attribute from a[n tables which can be used to identify the entity / record from tables uniquely (do not all attribute can become the superkey)
- Cadidate Key is super of key with the minimum attribute. Candidate Key may not contain the attribute from other tables so that candidate key beyond question superkey but not yet of course on the contrary.
- Primary Key
One of attribute from candidate key can be selected / determined to become the primary key with three criterion :
1. The Key more natural to be used as reference
2. The Key more simple
3. The Key well guarantedunique.
- Alternate Key is attribute from candidate key which is not chosen become the primary key.
- Foreign Key represent any attribute subjecting to primary key of at other tables. Foreign Key will be became of by an relationship owning kardinalitas one to many ( one to a lot of) or many to many ( a lot of to a lot of). Foreign Key usually is always placed at tables aiming to a lot of.
- Key represent a[n lexical attribute ( or gathering of lexical attribute) what its values always identify one
object instance
ERD ( ENTITY RELATIONSHIP DIAGRAM)
ERD is an network model using wording kept in system in abstraction.
Difference of between DFD and ERD :
- DFD represent an model of function network to be executed by system
- ERD represent the model of data network emphasizing at structure and relationship data
ELEMENT ERD
- ENTITY
At ER of Diagram Entity depicted with the long form persegi. Rntity is something that there is in real system and also abstraction of where on file data or where there are data.
- Relationship
At ER of Diagram relationship can be depicted with a lozenged. Relationship is natural relation that happened between entitas. Generally called with the elementary verb. so that facilitate to do the its relationship read.
- Relationship Degree
is amount entitas participating in one relationship. Degree which is often weared in ERD.
- Attribute
is the nature of or characteristic of each entitas and also relationship
- Kardinalitas
showing optimum tupel which can berelasi by entitas at other entitas
Degree Relationship
- Unary Relationship
is model relationship that happened between entity coming from entity set same.
- Binary Relationship
is model relationship that happened between 2 entitas.
- Ternary Relationship
representing relationship of between instance from 3 type entitas unilaterally.
KARDINALITAS
There are 3 kardinalitas relationship that is :
- One To One : Mount the relation one to one expressed with one occurence of at first entitas, only have one relation with one occurence of at secondary entitas conversely.
- One To Many or Many to One : Mount the relation one to a lot of is equal to a lot of to one depended from which direction of the relation of looking.For one occurence of at first entitas can have the many relation with the occurence of at secondary entitas, if on the contrary one occurence of at secondary entitas can only have the relationwith one occurence of at first entitas.
- Many To Many : happened by if each every occurence of at a entitas have the many relation with the occurence of at other entitas
NOTATION ( DIAGRAM E-R)
Symbolic Notation in diagram ER is :
- Long sided square express the gathering entitas
- Radian express the attribute
- Rhombic express the relationship gathering
- Mark with lines as link of between relationship gathering with the gathering of entitas and Gathering Entitas with its attribute
