namayana

Then we recreate the diagram to fix the problem on above diagram :
1. There’s no cardinality between entity BAGIAN and PROYEK. It should have been 1-N from BAGIAN to PROYEK. With logic : one BAGIAN may have many PROYEK, and one PROYEK may only have one BAGIAN.
2. The ternary relationship between entity PEGAWAI, PROYEK, & TANGGUNGAN seems strange.
It’s logical if the PEGAWAI has a relation with TANGGUNGAN (TANGGUNGAN be the weak entity because it’s dependant with the existence of the PEGAWAI). But if it’s also has a relation with PROYEK (be the ternary relationship), it may seems a little strange. It’s also supported with the existence of relation between PEGAWAI an PROYEK. Then why we must have a relation again with ternary relationship here? It seems irrational to me, so I delete the ternary relationship here, change them only with binary relationship (between entity PEGAWAI and TANGGUNGAN).
3. To determine the mapping later, we need to fix the relation PIMPIN between entity PEGAWAI and BAGIAN to gain the foreign key. So with the logic : one BAGIAN must be managed at least by one PEGAWAI, and one PEGAWAI must not managing one BAGIAN; we create the participation here partial-total from PEGAWAI to BAGIAN.


First Normal Form (1NF)

A table on the form said to be normal if I 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).



second Normal Form (2NF)

• Normal form 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
• We can see at the table of Pegawai at 1ST NORMALIZATION has the transitive dependency between it's entities.
  

Transitive dependencies:
NoPeg → TglLah
TglLah → Umur
So the table of pegawai can be :



third Normal Form (3NF)


3NF on the changes only at the Pegawai table, because there are non-primary key attribute is dependent on the primary key attribute is non other, in this case KDPos has Alm1 of attributes, so that we make a new table on the table so that the Pegawai is to be:

Database plan process (review)
Gather need user/business
Develop e-r model based on need user/business
Conversion e-r model to customer collection (table)
Customer normalization to cause the loss of anomaly
Implementations to database with make table to every customer that normalization

Database normalization
Normalization data base structure formation process so that a large part ambiguity can be caused.
Normalization stage is begun from lightest stage (1nf) up to tightest (5nf)
Usually only come up with level 3nf or BCNF because enough to produce tables have a certain quality good

why done normalization?
Optimalitation table structures
increase speed
cause the loss of data entering same
efficient in storage media use
decrease redundancy
avoid anomaly (insertion anomalies, deletion anomalies, update anomalies).
data integrity that increased
a table is said good (efficient) or normal if fulfill 3 criteria’s as follows:
if there decomposition table, so decomposition must be guaranteed safe (lossless-join decomposition). mean, after table elaborated / decomposition be new tables, new tables can produce table at first with same exactly.
take care functional dependence at the (time) of data change (dependency preservation).
doesn't break boyce-code normal form (BCNF)
if third criteria (BCNF) can not be fulfilled, so at least table doesn't break normal form third stage (3rd normal form / 3nf).


functional dependency
functional dependency describe connection attributes in a customer
a attribute said functionally dependant in other if we use attribute value to determine other attribute value.
symbol that used -> for representing functional dependency.
a read functionally determine
notation: a -> b
a and b attribute from a table. mean functionally a determine b or b depend on a, if and only if there 2 data lines with value a same, so value b also same
notation: a b or a b
the contrary from previous notation.
The concept of Functional Dependency is central to normalisation theory. FD is a semantic concept.It is concerned with a particular semantic relationship between the attributes of a relationship (usually has to be defined by an expert on the data). Finding all the FDs will result in a better model of the real world being modelled. Can be defined as a constraint on the set of legal relations.


A. Defintions

A B C D
a1 b1 c1 d1
a1 b2 c1 d2
a2 b2 c2 d2
a2 b3 c2 d3
a3 b3 c2 d4
In the relation above :

It can be stated that

A -> C is satisfied
C is functionally dependant on A or A determines C
As all A tuples that have the same value have the same C value

C->A isn’t satisfied

Other FDs are also satisfied

Functional dependency is trivial if satisfied by all tuples
ie A->A
In general, a functional dependency of the form X->Y is trivial if Y* X

FDs can be stated as holds – when every possible attribute combination complies
FDs are said to be satisfied when all stated attribute instances comply

B. Closure of a set of FDs

List all FDS that must always hold
Then some FDs can be logically implied using Inference Rules – Armstrongs Axioms

A (universal) relation U is used

1. Reflexivity Rule
If Y * X
Then X -> Y holds for all X,Y * U

2. Augmentation Rule
If X->Y and Z * U
Then Zx -> Zy for all X,Y * U


3. Transitivity Rule
If X-> Y and Y-> Z then X-> Z for X,Y,Z * U

Additional rules (which can be derived from above axioms)
4. Union Rule
If X-> Y and X-> Z then X-> YZ

5. Decomposition Rule
If X-> YZ then X-> Y and X-> Z

6. Pseudo Transitivity Rules
If X-> Y and TY -> Z then TX -> Z

C. Inference Rule example use
Given:
R= (A,B,C,G,H,I)

The set F of FDs:
A ->B
A-> C
CG -> H
CG -> I
B-> H

then the following can be inferred:
A-> H (transitivity A-> B, B-> H)

CG-> HI (Union CG -> H, CG -> I)

AG -> I ( A-> C given, AG-> CG augmentation, CG -> I given)

The set of all FDs that hold is denoted as F + and this is called the closure of the set of FDS

D. Identifying candidate keys and 3NF
FDs are a useful means of identifying candidate keys.
A superkey exists when each combination of values for a particular set of attributes can occur only once.
A candidate key is an attribute , or a set of attributes that gives a unique identity to each tuple in a relation. A candidate key is a minimal superkey.
If those relations with more than one candidate key, one is designated as the primary key
In the example above CG is identified as a candidate key

A relation R is in 3NF if for all FDs that hold on R of the form X-> Y, where X * R
And Y * R, at least one of the following holds :
• X -> Y is a trivial FD
• X is a superkey for R
• Each attribute y in Y is contained in a candidate key for R



second normal form (second normal form - 2nf)
normal form 2nf has been fulfilled in a table if fulfill form 1nf, and all attributes besides primary key, according to intact has functional dependency in primary key
a table doesn't fulfills 2nf, if there attribute the dependence (functional dependency) has only partial (only depend on some of primary key)
if found attribute doesn't has dependence towards primary key, so attribute must move or caused
functional dependence x -> y is said full if wipe off a attribute a from x mean y not again depend on functional.
functional dependence x -> y is said partial if wipe off a attribute a from x mean y still to depend on functional.
customer scheme r in the form of 2nf if every attribute non primary key A Є R depend on full according to functional in primary key r.

third normal form (third normal form - 3nf)
normal form 3nf has been fulfilled if fulfill form 2nf, and otherwise there attribute non primary key that has dependence towards attribute non primary key the other (dependence transitive).
boyce-codd normal form (BCNF)
Boyce-Codd normal form has compulsion stronger than third normal form. to be BNCF, customer must in the form of normal one and every attribute is forced to base on function in super attribute key.
in example under this is found seminar customer, primary key NPM + seminar.
student may take one or two seminars. every seminar wants 2 guides and every student is guided by one of [the] between 2 seminar guides. every only may take one seminar. in this example is NPM and seminar shows a guide.

normal form fourth and fifth
customer in the form of normal fourth (4 NF) if customer in BCNF and not full dependence many values. to cause the loss of dependence many values from one customer, we divide customer is two new customers. each full customer two attributes that has connection many values.
customer in the form of normal fifth (5nf) deal with property that called join without existence loses information (lossless join). normal form fifth (5 NF also called PJNF (projection join normal form). this case is very rare appears and difficult to detected according to practice.


references

http://en.wikipedia.org/wiki/Functional_dependency
www.doc.mmu.ac.uk/STAFF/P.Quick/fdnotes.doc

Database plan process (review)
Gather need user/business
Develop e-r model based on need user/business
Conversion e-r model to customer collection (table)
Customer normalization to cause the loss of anomaly
Implementations to database with make table to every customer that normalization

Database normalization
Normalization data base structure formation process so that a large part ambiguity can be caused.
Normalization stage is begun from lightest stage (1nf) up to tightest (5nf)
Usually only come up with level 3nf or BCNF because enough to produce tables have a certain quality good

why done normalization?
Optimalitation table structures
increase speed
cause the loss of data entering same
efficient in storage media use
decrease redundancy
avoid anomaly (insertion anomalies, deletion anomalies, update anomalies).
data integrity that increased
a table is said good (efficient) or normal if fulfill 3 criteria’s as follows:
if there decomposition table, so decomposition must be guaranteed safe (lossless-join decomposition). mean, after table elaborated / decomposition be new tables, new tables can produce table at first with same exactly.
take care functional dependence at the (time) of data change (dependency preservation).
doesn't break boyce-code normal form (BCNF)
if third criteria (BCNF) can not be fulfilled, so at least table doesn't break normal form third stage (3rd normal form / 3nf).

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

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.

What is a data flow diagram?

A data flow diagram (DFD) is a graphical description of the ebb and flow of data in a given context. A DFD allows you to identify the transformations that take place on data as it moves from input to output in the system. (DFDs pre-date UML diagrams, but still have a complementary role to play in describing systems.)

The Case Study below provides an example of a DFD used to describe the Open University's eTMA system (electronic Tutor Marked Assignment system). It uses the notation described in Table 1 below.

Data flow diagram levels

Context Level Diagram



This level shows the overall context of the system and its operating environment and shows the whole system as just one process. It does not usually show data stores, unless they are "owned" by external systems, e.g. are accessed by but not maintained by this system, however, these are often shown as external entities.


Level 1 (High Level Diagram)



This level (level 1) shows all processes at the first level of numbering, data stores, external entities and the data flows between them. The purpose of this level is to show the major high-level processes of the system and their interrelation. A process model will have one, and only one, level-1 diagram. A level-1 diagram must be balanced with its parent context level diagram, i.e. there must be the same external entities and the same data flows, these can be broken down to more detail in the level 1, e.g. the "enquiry" data flow could be spilt into "enquiry request" and "enquiry results" and still be valid


Level 2 (Low Level Diagram )



This level is a decomposition of a process shown in a level-1 diagram, as such there should be a level-2 diagram for each and every process shown in a level-1 diagram. In this example processes 1.1, 1.2 & 1.3 are all children of process 1, together they wholly and completely describe process 1, and combined must perform the full capacity of this parent process. As before, a level-2 diagram must be balanced with its parent level-1 diagram.

called also data flow diagram (dfd) describe system distribution into module smaller

will make user less will realize computer area to will understand system that be done

consist of one process and describe scope from a system

be level highest from dfd that describe entire input to system and outpour from system

system is limited by boundary (described by line broken offs)

there may not be any storage (storage)

describe process from dfd

give opinion according to comprehensive hit system that handled, show function or principal process, data current and eskternal entity

in level this maked data existence storage

for process is not detailed again in level furthermore so added simbol ‘*’ or ‘p’ by the end of process number

balance input and output (balancing) between diagram 0 with context diagram must be taked care be diagram that elaborate what process is there in diagram zero or level at on it

numberization level in dfd:

every process in dfd must has process specification

in top level method that used to describe process can by using descriptive sentence

in level detailer that is in process most under (functional primitive) want specification structured

process specification will be guide for programmer in will make program (coding)

method that used in process specification: process explanation in the form of story, decision table, decision tree

Something that beyond system, but he gives data into system or give data from system

symbolized with notation box

external entity doesn't belong part from system

nomenclature:

terminal name shaped noun

terminal may not has name same except the object really same

be place currences information

described with straight line that connect component from system

data current is showed with arrow direction and line is given name on data current that flow

data current flows between process, data storage and show data current from data shaped input for system

name gift guide:

data current name that consist of several word currents relateds with line continues

there may not be any data current the name same and name gift must reflect its contents

data current that consist of several elements can be declared with element group

koid word use ‘data’ and ‘information’ to give name in data current

sedapat may be data current name is written complete

rule other:

data current name that come into a process may not equal to secretory data current name from process

data flow that step into or out from data storage unnecessary given whose name:

simple data current and easy understood

data current describes entire item datas

there may not be any data current from terminal to data storage or on the contrary because terminal not part from system, terminal connection with data storage must pass process

process can cultivate data or data current enters to be data current out

process functioneds mentransformasi one or several input datas is one or several product datas as according to desirable spesification

every has one process or several inputs with produce one or several products

process often also called bubble

data storage be existing data repository in system

symbolized with a pair parallel line or two lines wrongly one sides side opened

process can take data from or give data to database

name gift guide:

name must reflect data storage

when does the name more than one word so be must be given sign continue

functioned to help system executant to interpret application in detail and mengorganisasi all data element that used system according to exactly so that user and has base explanation same about input, product, storage and process

in analysis stage, data dictionary is used as a means of communication between system analyst with user

in system planning stage, data dictionary is used to design input, report and database

data current in dad has global, explanation detailer visible in data dictionary

data dictionary holds the followings:

data current name: must be registerred so that reader that need furthermore explanation about a data current can look for it easily

alias: alias or name other from data can be written if (there are) any

data form: used to group data dictionary into its use sewaktu system planning

data current: show from which data flows and where does data aim

explanation: give explanation about meaning from data current

data current that come into and out from one process must equal to data current that comes into and out from process details in level/stage at under it

data current name that come into and out from one process must equal to data current name that enters to into and out from process details

total and name entitas outside from a process must equal to total and name entitas outside from process details

matters that must be paced in dfd that has more than one level:

must found balance input and output between one level and level next

balance between level 0 and level 1 seen in input/output from data current to or from terminal in level 0, while balance between level 1 and level 2 seen in input/output from data current to/from process concerned

data current name, data storage and terminal in every level must same if the object same
data current may not from entities outside direct aim entities outside another without pass a process

data current may not from direct data savings aim to entities outside without pass a process

data current may not from direct data savings aim another data savings without pass a process

data current from one direct process aims another process without pass a data savings best/can may be avoided

result from investigation a containing recommendation among others as follows:
doesn't take steps anything? is not found problem
do system maintenance? little problems
increase ability or user know-how
considering system modification according to total
laid problem that into system development plan soon done

why necessary tactics?
find all problems
detect problem appearance cause
determine correct solution
be done so that all system elements can get solution tender without disturb their activity

several tactics that can be done:
listen system executant opinion
don't give beginning solution
compare story several system executant persons towards case same
look at problem inkonsistensi logikal

input
product
file
data element
transaction volume and action document
data flow chart

system description in this time

input
product
file
data element
transaction volume and action document
data flow chart

analysis need
intensive interaction stage between system analyst with end where does system development team show the skill to get conception and user belief so that get good participation.
4 aims that want achieved:
explain system in its entirety
describe ideal information system
bring ideal information system to condition in this time with pays resource obstacle
give push towards user confidence into system development
method
question and answer
kuisioner
observation
analysis procedure
document observation

analysis need

resource obstacle
time
money
skill
technology
external factor
analysis need document
analysis directive: connection with user ends, process observation, troubleshoot in data collecting
user need: need actually, report need, training need and new system influence
system obstacle: explain time obstacle and cost, skill, technology and external factor
document shaped data collecting instrument, statistics consensus, data current according to logikal and physical, beginning data element in data dictionary.


generating systems alternatives

how does manner juxtapose system condition in this time with system condition ideal?
make alternative to break information system problem
best alternative applieds wisely
strategy choice
menytributed versus centralized processing
information decision change from centralized data processing to decentralized end user responsibility center
integrated versus menypersed database
system designer must considering data everything that enters in data base and come into file
surround strategy of system development
environment around important strategy in the case of pengambilalihan companies because information system from company other may be differ from to company in this time.

selecting the proper system

tactics compares: system is compared based on cost and profit relatively; there 3 system manners a said superiorer with another system if:
a has lower cost from b and profit both same
a has lower cost from b and a produce profit more than b
a and b has cost same but profit that produced a more many.
several methods komparasi system
break even point analyisis
payback period
menycounted payback period
internal rate of return

selecting the proper system
katagori cost
hardware
software
people
suppliers
teleccommunications
physical sites
cost details
compare information system cost passes system life, analyst memproyeksi what cost change for and there 3 information system cost models that is linear, eksponensial and step function

selecting the proper system

information system cost can happen once and can also happen chronically.
information system cost that once that is ontime cost and development cost that moment system development.
information system cost that continually mengantaranya reccuring cost with operational cost where does this cost happen moment information system operate every day.

mempresentasi system study

do presentation in a word
decrease technique explanation in detail
mempretasi clearly by means of help visual
if use model uses for example medium laptop so that informativeer
emphasize profit from information system proposal with a few alternative appropriate condition that undergone to company.

decision continues or not
if company to decide to develop system so information departement will do process furthermore that is system design process.
if on the contrary so system development life cycle (sdlc) be stopped.
frequently be found problem with study system and and usually top management will ask melakukannya reworking towards study system.
model will explain stages some part that repeated and sometimes information departement will make to repeat stage before explain study system.
alternatively, decision to repeat a stage sdlc previous or bot to speak of go – no –go decision.