IT for Mgt Module 2

8/6/2019 IT for Mgt Module 2

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Module 2

Database


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Introductio

n

The term database originated withinthe computing discipline.

Although its meaning has beenbroadened by popular use, even toinclude non-electronic databases, weconcentrate on computer databases.


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Definitio

n

Acomputer database is a structuredcollection of records or data that isstored in a computer system so that acomputer program or person using aquery language can consult it toanswer queries

The records retrieved in answer toqueries are information that can beused to make decisions.


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Definitio

n

The term database refers to the collectionof related records, and the software shouldbe referred to as the database

management system or DBMS.

When the context is ambiguous, however,many database administrators andprogrammers use the term database to

cover both meanings.


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Microsoft Office Access Microsoft Office Access, previously

known as Microsoft Access, is a relationaldatabase management system from

Microsoft which combines the relationalMicrosoft Jet Database Engine with agraphical user interface and softwaredevelopment tools.

It is a member of the 2007 Microsoft Officesystem


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Use of

Access

Skilled software developers and dataarchitects use it to developapplication software.

Relatively unskilled programmers andnon-programmer "power users" canuse it to build simple applications.

It supports some object-orientedtechniques but falls short of being afully object-oriented development tool


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Uses

Access is used by small businesses, withindepartments of large corporations, and byhobby programmers to create ad hoc

customized desktop systems for handlingthe creation and manipulation of data.

Access can be used as a database for basicweb based applications hosted on

Microsoft's Internet Information Servicesand utilizing Microsoft Active Server PagesASP


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Prime benefit

One of the benefits ofAccess from aprogrammer's perspective is its

relative compatibility withSQL(structured query language)

Queries may be viewed and edited asSQL statements


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File exte

nsio

ns

Microsoft Access saves information under the following fileextensions: .mdb - Access Database (2003 and earlier)

.mde - Protected Access Database, with compiled macros(2003 and earlier)

.accdb - Access Database (2007) .accde - Protected Access Database, with compiled macros

(2007) .mam - Access Macro .maq - Access Query

.mar - Access Report .mat - Access Table .maf- Access Form .adp - Access Project

.adn- Access Blank Project Template


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Getti

ng started

First of all you need to understandhow Microsoft Access breaks down a

database. Some keywords involved in this

process are: Database File, Table,Record, Field, Data-type


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Database andTables

Database File: This is your main file thatencompasses the entire database and thatis saved to your hard-drive or floppy disk.

Example) StudentDatabase.mdb

Table: A table is a collection of data abouta specific topic. There can be multipletables in a database.

Example #1) StudentsExample #2) Teachers


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Field a

nd Datatypes

Field: Fields are the different categorieswithin a Table. Tables usually containmultiple fields.

Example #1) Student LastNameExample #2) Student FirstName

Datatypes: Datatypes are the properties ofeach field. A field only has 1 datatype.

FieldName) Student LastNameDatatype) Text


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Example of a database structure

STUDENT database structure

Field name Type Length

Code Numeric 4

Name String 20

Date-of-Birth Date

Address line-1 String 20




Marks-English Numeric 3

Marks-Hindi Numeric 3

Marks-Physics Numeric 3

Marks-Chemistry Numeric 3

Marks-Maths Numeric 3


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Creati

ng a database


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Creati

ng a database

When Microsoft Access first starts up, a dialog box isautomatically displayed with options to create a newdatabase or open an existing one. If this dialog box isdisplayed, click Blank Access Database, and then

click OK.

If you have already opened a database or closed thedialog box that displays when Microsoft Access startsup, click New Database on the toolbar, and thendouble-click the Blank Database icon on the

General tab. Specify a name and location for the database and

click Create.


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Create a database without using

the Database

Wizard


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Example of a table


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Double-Click on"Create table inDesign view". You get this Design

View


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Defining fields

Define each of the fields in your table.

Under the Field Name column, enter

the categories of your table. Under Data Type column, enter the

type you want for you categories.

Under t

he Descriptio

ncolum

n, e

nterthe text that describes what your field

is. (This field is optional).


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Data type It is the attribute of a variable or field that

determines what kind of data it canhold. For example, in a Microsoft Access database, the

Text and Memo field data types allow the field to

store either text or numbers, but the Numberdata type will allow the field to store numbersonly.

Number data type fields store numerical datathat will be used in mathematical calculations.

Use the Currency data type to display or

calculate currency values. Other data types are Date/Time, Yes/No, Auto

Number, and OLE object (Picture).


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For our tutorial enter the followingitems:


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Primary key Keys are one or more fields (columns) whose value or

values uniquely identify each record in a table.

A primary key does not allow Null values and mustalways have a unique value.

A primary key is used to relate a table to foreign keysin other tables.

In the above example, make the SocSec # field theprimary key, meaning that everystudent has a socialsecurity number and no 2 are the same.

To do this, simply select the Soc Sec # field andselect the primary key button

After you do this, Save the table


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Now, enter t

he data

Click on the Datasheet View andsimply start entering the data into

each

field.


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Manipulati

ng Data

Adding a new row

Simply drop down to a new line and enter theinformation

Updating a record

Simply select the record and field you want toupdate, and change its data with what you want

Deleting a record Simply select the entire row and hit the Delete

Key on the keyboard


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Form desig

n

AForm is nothing more than a graphicalrepresentation of a table.

You can add, update, delete records in your table byusing a form.

Although a form can be named different from a table,they both still manipulate the same information andthe same exact data. Hence, if you change a record ina form, it will be changed in the table also.

A form is very good to use when you have numerous

fields in

a table.Th

is way you can

see all the fields i

none screen, whereas if you were in the table view

(datasheet) you would have to keep scrolling to getthe field you desire.


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Form

Wizard

It is a very good idea to create a formusing the wizard, unless you are an

advanced user a

nd k

now w

hat youare doing. Microsoft Access does a

very good job of creating a formusing the wizard.


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Create a

Form

The following steps are needed to create a basic form:

Switch to the Database Window. You can do this bypressing F11 on the keyboard.

Click on the Forms button under Objects on the leftside of screen

Double click onCreate FormUsing Wizard

On the next screen select the fields you want to viewon your form. Most of the time you would select all ofthem.

Click Next (Contd in the next page)


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C

reate aF

orm (C

ontd)

Select the layout you wish

Click Next

Select the style you desire...HINT: if you plan onprinting your form, I suggest you use a lightbackground to save on printer toner and ink

Click Next

Give your form a name, and select Open the Formand enterinformation

Select Finish

You should see your form. To adjust the design ofyour form, simply hit the design button (same as withthe tables), and adjust your form accordingly


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Report A report is an effective way to

present your data in a printed format.

Because you have control over thesize and appearance of everything ona report, you can display theinformation the way you want to see

it.


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C

reate a Report As with the Form, it is a very good idea to create a

report using the wizard, unless you are an advanceduser. Microsoft Access does a very good job using thewizard to create reports.

Switch to the Database Window. You can do this bypressing F11 on the keyboard.

Click on the Reports button under Objects on theleft side of screen

Double click onCreate Report Using Wizard

On the next screen select the fields you want to viewon your form. Most of the time you would select all ofthem.

Click Next (Contd in the next page)


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C

reate a Report (C

on

td) Select if you would like to group your files. Keep repeating

this step for as many groupings as you would like. Click Next Select the layout and the paper orientation you desire Click Next Select the style you desire...HINT: if you plan on printing

your report, I suggest you use a light background to saveon printer toner and ink

Click Next Give you report a name, and select Preview the Report Select Finish

You should see your report. To adjust the design of yourreport, simply hit the design button (same as with thetables), and adjust your report accordingly


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Basic queries usin

g SQL In Microsoft Access you can use

queries to extract information (data)

from one (or more) tables (or fromother queries).

The information you retrieve can belimited by the definition of your

query.


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A

typical SQL statemen

t A typical SQL statement resembles

the following:

SELE

CTDept

Code,

CrsNum,

Title

FROM

Courses WHERE DeptCode = COMM;

There are four parts to this statement:

1. SELECT

specifies which fields to project 2. FROM specifies the

underlying table (or tables) for the query;


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A typical SQL statement (Contd)

3. WHERE

specifies one or more conditionsthat each record must satisfy in order tobe included in the results set;

4. ; (semicolon) all SQL statementsmust end with a semicolon (but if youforget it, Access will add it for you).


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IT for Mgt Module 2

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