Nota database object query

LESSON 54
DATABASE OBJECT-QUERY
DEFINE THE QUERY AS ONE OF THE DATABASE
OBJECTS
A Query is database object that retrieves specific information from a
database.
For example, you can retrieve a student’s name and address from the
database.
With Access Queries, you can do the following :
View specific data from Table.
Perform calculations on selected records.
Delete record from a table.
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You can create new Queries using one of the methods.
Create query in Design View.
Create query by using wizard.
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CREATING A RELATIONSHIP
You need to create the relationship between Tables
before you can create Queries.
- See Demonstrations From the CD
Referential Integrity is a set of rules that ensures relationships between
Tables within a database are all valid.
CREATING A QUERY IN DESIGN VIEW
CREATING A QUERY BY USING WIZARD
TO RUN A QUERY
EXTENSION : USING PARAMETER
Parameter is a value in a specific field used to retrieve information from the
Query such as BioLife in “Brand” field.
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Another example, you can type in the date of purchase of vitamin C for the
month of August.
Only the information on vitamin C for the month of August which is specified
in the perimeter will be displayed.
It is used when searching for a particular piece of information. This enhances
the system performance speed.
LESSON 55
DATABASE OBJECT-FORM
DEFINE THE FORM AS ONE OF THE DATABASE
OBJECTS
A Form is a database object that allows users to
add, modify and view information.
Form can be created based on the Table or Query.
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A Form is an organised and formatted view of selected fields from selected
Tables or Queries.
By using Table, you need to scroll down to fill in the new data. This data
entry process will take time.
However, when From is used, it is easier as you need to click on the new
record button to fill in the new data.
This will speed up the data entry process.
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When you add new data into Forms, you are automatically also adding the
data into the Table.
When you modify data on Forms, you are automatically also modifying the
data in the Table.
You can create new Form using one of the methods.
Create form in Design View.
Create form by using wizard.
CREATING A FORM IN
DESIGN VIEW
CREATING A FORM BY
USING WIZARD
ENTERING DATA IN A FORM
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EXTENSION : MAIN FORM AND SUBFORM
Sometimes, you want to get the information from two Tables to design a
Form.
For example, you want to design an invoice form to contain customer and
product details.
In this situation, you need a main form and a subform. A main form contains
customer information.
A subform is inserted into a main form.
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The invoice form gets information from two Tables that are Customer Table
and Product Table.
In the invoice form, the Customer Table supplies data such as
CustomerName, Address and ContactNumber for the main form.
Product Tablegives data for the subform. It contains specific details such as
ProductID, Details, Quantity and Price purchased by the customer.
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By using mail form and subform, you can view the information together. The
main form and subform appear in the same window.
LESSON 56
DATABASE OBJECT-REPORT
DEFINE THE REPORT AS ONE OF THE DATABASE
OBJECTS
A Report summarises information from the
database.
A Report is a database object that presents
selected information from Tables or
Queries, for printing purposes.
When designing a Report, consider the
point you are making, the audience and the
level of information they needed.
Reports can be created based on the Table or Query.
You can create new Queries using one of the methods.
Create report in Design View.
Create report by using wizard.
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CREATING A REPORT IN DESIGN VIEW
CREATING A REPORT BY USING WIZARD
EXTENSION : PUBLISH YOUR REPORTS TO WEB
PAGE
A Web Page is resource of information that can be accessed through a Web
browser.
The purpose of publishing your Reports on the Web is to allow people from
multiple locations in your organisation to view your Report.
For example, if your company sells many items, the inventory report has to
be updated weekly. You could produce inventory Report and export that
Report as an HTML file. The Report has to be converted to HTML format
before being published.
This file is transferred to the Web Server and can be accessed by all staffs in
the organisation.
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LESSON 57
DATA MANIPULATION
Data manipulation refers to the operations of accessing, locating, organising,
modifying and managing data contained in the database.
Basic operations of data manipulation :
Update
Insert
Delete
Retrieve
Sort
Filter
Search
UPDATING RECORDS
The Update operation is used for changing data in a database Table.
- See Demonstrations From the CD.
INSERTING RECORDS
The Insert operation is used for adding records to a database Table.
DELETING RECORDS
The Delete operation is used for removing records from a database Table.
RETRIEVING RECORDS
The Retrieve operation is used for retrieving records from a database Table.
SORTING RECORDS
The Sort operation is used for sorting records in a records in a database
Table.
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FILTERING RECORDS
The Filter operation is used for filtering records from a database table.
Instead of displaying all the records in a Table, you can use a filter to display
only those records that you want to see or edit.
SEARCHING RECORDS
The Search operation is used for finding record from a database table.
You can use the Find function in Microsoft Access to search for the records.
You can use the “Find” feature to locate one or more records to find specific
data.
EXTENSION : DATA EXPORT
The transferring of data from a format to another is called the data export.
For example, in Microsoft Access Table, Queries, Forms and Reports can be
exported to a spreadsheet format.
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Sometimes, you will come across situations where your data is stored in
Microsoft Access but you need to move or copy it to Microsoft Excel.
For example, you might want to give your report to a group of users who
like to view the data in the form of a chart or graph.
You might also want to manipulate your data using line chart where you can
see the shipping date clearer.
Data Export is a lot easier than retyping the data in a spreadsheet.
LESSON 58
PHASES OF SYSTEM DEVELOPMENT
The system development phase is a series of steps used to develop a
database program.
These phases describe the processes that system developers carry out in
order to develop a database program.
OVERVIEW OF SYSTEM DEVELOPMENT PHASES
Analysis Phase
During the Analysis Phase, system developers will perform problem analysis
by finding out the needs of target users.System developers also identify the
input, process and output for the new system.
Design Phase
Based on the needs of target users, the system developers will design an
Entity Relationship Diagram (ERD). This phase is known as the Design
Phase.
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Implementation Phase
Implementation Phase is the phase where system developers create
database using database software.
Testing Phase
The system will be tested by the target users in the Testing Phase.If there is
any error detected, the system developers will fix the error.
Documentation Phase
System developers will produce the documents for the program during the
Documentation Phase.
Maintenance Phase
The system developers continue to provide support during the Maintenance
Phase. They monitor the system performance and make changes when
needed.
EXTENSION : PRACTICES OF DEVELOPING A NEW
INFORMATION SYSTEM
Some practices of developing a new information system:
Work as a group
When you want to develop an information system, you must work as a
group. All group members must work together to complete tasks like data
entry and analysis.
Involves many people
Involve as many people as possible in your project. This means that you
should not only think of people in your group but also friends and teachers
who will use your information system.
Willing to accept changes
Create a culture among yourselves to accept changes. For example, each of
you should try changing roles throughout your project so that everyone
learns each other’s responsibilities.
You must be willing to accept changes when others give comments or
recommendations.
Share with others
Tell as many people as you can about what your group is doing. This
encourages sharing of ideas and learning from one another.
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LESSON 59
ANALYSIS PHASE
ANALYSIS PHASE OF SYSTEM DEVELOPMENT
The Analysis Phase is the first phase of
system development.
In this phase, the system developers
would need to define problems faced by
target users.
The target users will indicate their
requirements. They need to give a
description of what a system must do
and the main functions of the system.
By doing this, the system developers can define the purpose of the system.
It would help system developers set the focus of the system.
PROBLEM ANALYSIS
During the Analysis Phase, the system developers will interview the target
users to find out their needs.
For example, in the School Resource Centre,
the system developers found out that the
target users are currently using the manual
system.
They are facing difficulties in keeping resource
materials organised as the volume of books is
increasing.
The target users require a new system that is a School Resource System to
register and catalogue their books.
By doing problem analysis, the system developers would have to understand
the needs of the target users.
The new system should store all book
details as in a manual system.
The new system should be faster, easier to
use and have a larger storage.
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In the School Resource System, the system developers need to identify the
input, process and output for the system.
The system developers identify the input, for example AuthorName,
PublisherName, CategoryName, BookTitle and BookPrice.
The system developers identify the process for all the system. All new books
purchased by the School Resource Centre would have all their data keyed
into the School Resource System.
The system developers identify the output for the system. For example, the
books which have been keyed in will be printed out as document references
in the School Resource Centre.
By doing this problem analysis, the system developers can come up with the
design of the system.
EXTENSION : STANDARDISATION
Standardisation is a set of rules and procedures that system developers
require target users to accept and follow.
For example, system developers need standardisation for the coding of stock
name. In Analysis Phase, system developers need to understand the terms
used by target users in order to set a standardisation for input, process and
output.
If the stock code is set to S00001, the target user must follow the standard
by using the prefix S for the rest of the stock code. For example S00002,
S00003 and so on.
Standardisation is used to help people working on the same development
project to produce consistent results.Without standardisation, the system
will not function correctly. Setting standards avoids confusion in the whole
process of system development.
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LESSON 60
DESIGN PHASE
DESIGN PHASE
The Design Phase is the second phase in system development. It refers to
the planning of the system design.
GUIDELINES FOR DESIGNING A DATABASE:
Choose data
Choose the neccessary data you need to store in the database. For example,
in the School Resource System, the necessary data are Author, Book,
Category and Publisher.
Ensure table contains the necessary data
In this School Resource System, there are four Tables involved, namely
Author, Book, Category and Publisher.
From the analysis, the system developers found out that:
An author can have one or more books.
A publisher has one or more books.
A category has many books.
Determine field
You need to ensure Tables contain the necessary data.
You need to determine what fields to include and the suitable data type
format for those fields.
Author Table consists of AuthorID and AuthorName.
Book Table consists of BookID, BookTitle and BookPrice.
Category Table consists of CategoryID and CategoryName.
Publisher Table consists of PublisherID and PublisherName.
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These are the technical plans we designed during the Design Phase.
In the Design Phase, the system developers will seek to provide input
interface and output interface.
System developers will provide an input interface where the user can do
data entry.
The user can also retrieve information from a database using an output
interface.
ENTITY RELATIONSHIP DIAGRAM
Entity Relationship Diagram (ERD) is one of the diagrams that show how
Tables are organised and related to one another.
There are two symbols used in an
Entity Relationship Diagram.
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In the School Resource System, system developers can use the Entity
Relationship Diagram to describe all Tables and their fields.
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EXTENSION : MOCKUP
A mockup is a sample of the input or output that contains actual data.
A mockup is needed when handling a big database program so that the
system developer and target user understands the system better.
The system developers show mockups to users for their approval.
It is important to involve users during input and output design stages
because users finally will work with those designs.
Users must give their approval on all inputs and outputs before system
developers proceed with database design. A mockup ensures input and
output designs meet the needs of users.
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LESSON 61
IMPLEMENTATION PHASE
The Implementation Phase is the third phase of system development.
In the Implementation Phase, the system developers will convert the
technical plan and design plan into a computer program.
The Implementation Phase is the phase where a system is created.
CREATING DATABASE
In this phase, a system developer uses
database software such as Microsoft Access
as the development tool to create a Scholl
Resource System.
CREATING TABLES
You can use Design View to create tables to store data. You are to create
four tables: Author, Book, Publisher and Category for the School Resource
System.
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ASSIGNING TABLE RELATIONSHIP
See Demonstrations From the CD.
Referential Integrity is a set of rules
that ensures relationships between
Tables within a database are all valid.
CREATING QUERIES
CREATING FORMS
You can use Forms to perform data entry and retrieve related data.
CREATING REPORTS
You can use Reports to summaries information from the database.You can
create new Report using wizard.
You can use Reports to retrieve information from the database using Table
or Query.
EXTENSION : TYPES OF RELATIONSHIP
One-To-One
For example, each member has only one address record.
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One-To-Many
For example, each book has only one category. Each Category has many
books.
One-to-one relationships happen when there is only one record in Library
Member to another one record in Member Contact.
One-to-many relationships happen when each record in Book Category has
many related records in Book.
LESSON 62
TESTING PHASE
Testing Phase is the fourth phase of system
development. It involves the system
developer and user in the Testing Phase.
To ensure the quality of a database, the
system developers act as quality controllers
and will run tests on it.
The purpose of system testing is to ensure
the system runs correctly and is error free.
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DATA ENTRY IN TESTING PHASE
Before testing the database, data must be entered into the Tables. Enter
data for four Tables : Author, Book, Category and Publisher.
TESTING ON DATABASE OBJECT
You can do the testing to verify that each database object is functioning.
You need to conduct testing to detect any error present.
TESTING ON FUNCTIONALITY OF THE SYSTEM
You can also conduct a test to verify that all systems work together
properly.
EXTENSION : DATA VALIDATION
Validation is the process of comparing the data to a set of rules or values to
determine if the data is accurate.
For example, the quantity a user
keyed in should be less or equal to
1000. The message will pop up if
the quantity is over 1000.
A range check is another example of a validity check.
For example, the salary a user keyed in should be between 900 and 1500.
The message will pop up if the salary is over 1500.
By implementing data validation, it minimises data entry errors.
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LESSON 63
DOCUMENTATION PHASE
The Documentation Phase is the fifth phase in system development.
Documentation refers to the written materials generated throughout phases
of system development.
DOCUMENTATION
Documentation is very important when the system requires changes in the
future. Documentation tells new system developers what was done in the
program.
It helps to reduce the amount of time a new system developer spends
learning about existing programs.
A number of documents are produced during the development of a new
computer application.
User Manual
The User Manual helps the user to use the system.
User Manuals are written in simple language rather
than technical language.
The User Manual should cover how to run the
system, how to enter data, how to modify data and
how to save and print reports.
The User Manual should include ways to overcome
errors.
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Technical Documentation
In Documentation Phase,
User Manual and Technical
Technical Documentation is used by system
developers as a reference.
Technical Documentation is useful for system
improvement.
Documentation are found in
a folio.
You need to gather all the
documents from the system
development phases into a
folio.
You can compile your
Technical Documentation
in the form of a hard
copy.
Documentation can also
be gathered in a soft
copy.
All documentation must be ready by the end the system development. The
system developers should ensure that all documentation is complete and
accurate.
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EXTENSION : CREATING A HELP FILE
A Help File is a documentation file that brings together help information of
all the database objects in a project.
This file is a guideline for the user when the user needs
any help in operating the program.
System developers will create a Help File at the final
stage of a project.
For example, system developers can use Help
Generator Wizard to create a Help File for School
Resource System.
LESSON 64
MAINTENANCE PHASE
The Maintenance Phase is the last
phase in system development.
Maintenance refers to the changes in
the system by fixing or enhancing its
functionality.
System developers are involved in the
Maintenance Phase.
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System maintenance involves checking, changing
and enhancing to improve its performance.
All systems need to be maintained to take care of
new requirements that were not discovered
previously.
CORRECTIVE MAINTENANCE
Corrective Maintenance is changing maintenance carried out to repair an
error in system design.
This maintenance is used when errors are detected and need to be rectified.
For example, in the School Resource System, you need to add the
International Standard Book Number (ISBN) field.
PERFECTIVE MAINTENANCE
Perfective Maintenance is a system maintenance performed to improve a
computer program.
Perfective Maintenance is done when the users require changes in the
interfaces.
For example, in the School Resource System, you can modify the layout of
the Book Form by changing the font colour, type, size and adding "Book
Form" title.
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PREVENTIVE MAINTENANCE
Preventive Maintenance is a
maintenance aimed at the
prevention of future breakdowns and
failures.
This maintenance is carried out
when there is a possibility or risk of
failure while operating.
For example, in the School Resource System, you want to assign a password
before a user accesses the database.
Some users may only be allowed to view data in a
particular Table.
Some may only be allowed to add records to a
Table while others may be given the right to view
and modify information.
The use of passwords thus helps to prevent unauthorised access to
confidential information.
Preventive Maintenance needs to be done to avoid possible future problems.
EXTENSION : BACKUP A DATABASE
Backup is a process of making copies of
data. To backup a database involves
the backup of a whole database
system.
The backup can be used to restore the
original data to prevent data loss
caused by virus or power failure.
Backup of database should be done regularly. In this way, you can still
access to your backup if anything goes wrong.
Backups should be done on an external medium with a USB memory stick,
external hard drive, CD, DVD or server.
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LESSON 65
DEVELOP A DATABASE PROJECT
PROJECT WORK
- See example From the CD.
LESSON 66
WEB-BASED APPLICATIONS
Technological advancements in large database development and high speed
digital transmission networks will result in global information systems.
These developments will
influence how people interact
with information. Through the
Internet, a user can get fast
responses and have two-way
communication using video
conferencing and e-mail.
By using the global information
systems, people from all over the
world can be equipped with
knowledge in many areas.
GLOBAL INFORMATION SYSTEM
Web-based applications are delivered to users from a Web server over the
Internet.
Web-based applications store information in a database system such as
Microsoft SQL Server or Oracle.
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GLOBAL RESOURCE CENTRE
Global Resource Center is a Web-
based information system used in
developing human resources for
health.
Global Resource Center offers a global library of human resources for health,
focusing on developing countries.
For example, healthcare personnel can store their individual details in this
database. This database can be accessed by a country that needs the
healthcare support.
The healthcare personnel can then be contacted via this Web-based
database and called to the service.
By using this system, countries with health needs can be met. This resources
center is managed by Capacity Project and USAID-funded global project.
GLOBAL DISASTER ALERT AND COORDINATION
SYSTEM
Global Disaster Alert and Coordination System is a
Web-based disaster information management system.
Global Disaster Alert and Coordination System stores
disaster events in the database.
The data is automatically analysed to determine the help needed by the
affected country.
For example, from the Current Disaster Events column, you can be informed
of the flood that happened in China.
This alerts people of the surrounding regions to evacuate and move to safer
places.
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People living in Vietnam and Laos will take necessary precautions when
floods happen in China.
By using this system, it helps to coordinate the international responses
during the disaster.
Global Disaster Alert and Coordination System is a joint initiative of the
United Nations and European Commission.
GLOBAL DATA MONITORING INFORMATION
SYSTEM
Global Data Monitoring Information System is a
Web-based information system that collects data
worldwide to sustain social and economic
progress in all countries.
Global Data Monitoring Information System is to
help countries overcome problems of poverty,
health and education.
For example, data collected on HIV statistics is analysed and it was found
that millions of death were caused by AIDS.
By using this system, medical assistance can be promptly given to those
countries affected.
It is an effort by Millennium Development Goals under the World Bank
group.
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