g u i stud

K. J. Somaiya Institute of Engineering & Information Technology

Department of Information Technology/GUI & DBM(Sem: III)

K. J. Somaiya Institute of Engineering

And

Information Technology Sion, Mumbai - 22

Department: Information Technology

Academic year: 2011-12

Lab Manual

Class - SE Sem - III

SUBJECT: GUI AND DATABASE

MANAGEMENT

Version: 2



K.J.SOMAIYA INSTITUTE OF ENGINEERING AND

INFORMATION TECHNOLOGY

DEPARTMENT OF INFORMATION TECHNOLOGY

CLASS: S.E. SEMESTER: III

SUBJECT: GUI AND DATABASE MANAGEMENT

_____________________________________________________________________

List of Experiments

1. ER model and reduction of ER model to relational model.

2. Implementation of database using SQL server

3. Modification of database schema

4. Implementation simple SQL queries

5. Implementation of advanced SQL queries

6. Implementation of Joins

7. Implementation of Views

8. Layout of GUI & Study of various controls used in VB 6.0

9. Implementation of GUI using VB 6.0, Business logic development

10. Database connectivity and working module

Seema Yadav

Subject Incharge



Experiment No:1

Aim: ER model and reduction of ER model to relational model.

Software used: MS word.

Theory : Entity relationship model is a data model which represent the overall logical structure of

database and it is very useful in mapping the meanings and interactions of real world enterprises

onto a conceptual schema.

The E-R model employs three basic notations:

Entity sets: An entity set is a set of entities of the same type that share the same properties .(an

entity is a real world object)

Relationship sets: Relationship set is a set of relationships of the same type.(relationship is an

association among several entities)

Attributes: Attributes are properties of entity set used to describe it.

Different types of attributes are as follows:

1. Simple and composite attributes. In our examples thus far, the attributes have been simple;

that is, they are not divided into subparts. Composite attributes,on the other hand, can be divided

into subparts (that is, other attributes). For example, an attribute name could be structured as a

composite attribute consistingof first-name, middle-initial, and last-name. Using composite

attributes in a design schema is a good choice if a user will wish to refer to an entire attribute on

some occasions, and to only a component of the attribute on other occasions. Suppose we were to

substitute for the customer entity-set attributes customer-street and customer-city the composite

attribute address with the attributes

street, city, state, and zip-code.2 Composite attributes help us to group

together related attributes, making the modeling cleaner

2. Single-valued and multivalued attributes. The attributes in our examples all have a single value

for a particular entity. For instance, the loan-number attribute for a specific loan entity refers to

only one loan number. Such attributes are said to be single valued. There may be instances where

an attribute has a set of values for a specific entity. Consider an employee entity set with the

attribute phone-number. An employee may have zero, one, or several phone numbers, and

different employees may have different numbers of phones. This type of attribute is said to be

multivalued.

3. Derived attribute. The value for this type of attribute can be derived from the values of other

related attributes or entities. For instance, let us say that the customer entity set has an attribute

loans-held, which represents how many loans a customer has from the bank. We can derive the

value for this attribute by counting the number of loan



entities associated with that customer. As another example, suppose that the customer entity set

has an attribute age, which indicates the customer’s age. If the customer entity set also has an

attribute date-of-birth, we can calculate age from date-of-birth and the current date. Thus, age is a

derived attribute. In this case, date-of-birth may be referred to as a base attribute, or a stored

attribute. The value of a derived attribute is not stored, but is computed when required.

In extended E R model we have three additional concepts:

Specialization: The process of designating the subgroupings within an entity set is called

specialization( finding specialized attributes)

e.g. in entity set person we have two types of entities like customer and employee. Both are

person but employee have specialized attribute salary and customer have rating.

Generalization: It is a top down design process in which multiple entity sets are synthesized into

a higher level entirty set on the basis of common features.

e.g. customer entity set and employee entity set both have common attributes like name, address,

age which can be used as attributes of higher level entity set person.

Aggregation : it is an abstraction through which relationships are treated as higher level entities.

The most important use of the E-R diagram is it represents some constraints like total and partial

praticiplation , one to one, many to many, many to one, one to many mapping etc.



Symbols used in E R diagram:

Entity set

Weak entity set

Relationship set

Identitying

relationship set

Many to one cardinality

One to many cardinality

One to one cardinality

many to many cardinality

E

E

R

R

Attribute

Multivalued attribute

Derived attribute

Primary key

Partial key

Composite Attribute

Total participation

Partial participation

Specialization or generalization

A

A

A

A

A

A

R

R

R

R

ISA

R

R



Reducing ER model into relational model.

1) Any strong entity set E having attributes a1, a2,…,an is reduced into a relation schema

called E with n distinct attributes i.e. a separate relation with name E and n distinct

coloumns.

2) Any weak entity set A having attrinutes a1, a2,..n and a strong entity set B on which A

depends, having primary key attributes as b1, b2, …, bn is reduced into a relation

schema called A with one attribute for each member of set

{ a1, a2,…, an} U {b1, b2, ……. , bm}

3) Any relationship set R having a1,a2,…,an as a set of attributes formed by union of the

primary keys of each of the entity sets participating in R and b1, b2,….,bm as set of

descriptive attributes is reduced into a relation schema called R with one attribute for

each member of the set

{a1, a2, …. ,an} U {b1, b2, …., bn}

Primary key of relationship set is decided as follows

For binary many to many relationships the union of primary key attributes from the

participating entity sets is primary ey.

For binary one to one relationship set the primary key of either of the participating entity

set can be chosen as the primary key.

For binary many to one or one to many relationship set the primary key of the entity set on

the many side of the relationship set serves as the primary key.

For n-ary relationship sets without any arrows on its edges, union of the primary key

attributes of participating entity sets is a primary key.

For n-ary relationship sets with an arrows on one of its edges, union of the primary key

attributes of participating entity sets is a primary key.

To remove redundancy we generally make separate relation schema for many to many

relationship set with primary key and other attributes as mentioned above.

For one to one we combine relation schema of relationship set with relation schema of

either sides of entity sets relation schema.

For one to many and many to one we combine relation schema of relationship set with

relation schema of entity set on many side entity set.

We don’t make separate relation schema for identifying relationship set.



Every composite attribute A having subparts a1, a2,…,an is represented by separate

column for each subpart in relation schema of the associated entity set.

For multivalued attribute separate schema is form having columns as attributes of primary

key of associated entity set and a column for multivalued attribute

For disjoint generalization/specialization create separate relation schemas only for every

lower level entity set(higher level entity set’s attributes are inherited so add columns for

same) and not for higher level entity set.

For overlapping generatlization/specialization create separate relation schemas for higher

level as well as lower level entity sets.

Also include the foreign key constraint in lower level entity set for the primary key

attributes of higher level entity set.

No separate relation is required to represent the aggregation the relation created from the

defining relationship is used instead

(design schema for relationship set treated as entity set carefully)

Conclusion:

Hence we have studied the ER data model consisting of a set of basic objects called

entities & relations among those objects.It is intended primarily for database design process by

following the specification.

Reference book: Database System and concepts

Author: Henry F.Korth,Sliberchartz ,Sudarshan

Publication: Tata McGraw Hill



Experiment No:- 2

Aim : To implement the database using relational model design in experiment 1 .

Creation of Database with proper constraints( Pk, Fk etc).

Data Insertion into Database using insert statement(at least 5 records per table).

Applying different constraints- check , unique, not null etc.

Drop table.

Resources Used : Windows Xp professional, MY SQL .

Theory : After design of relational schema next step is to implement the database on machine

using Ms. SQL Server 2000.

Implemention can be done using SQL queries or enterprise manager.

Implementation Using Queries: To create database use query.

create database database_name;

Now database is created successfully . To use it use query

use database_name;

To create relation in this database use query

create table table_name(

attribute_name 1 domain,

attribute_name 2 domain,

attribute_name 3 domain [not null],

.

.

.

attribute_name n domain,

[ constr_pk1:

primary key( list of required and above defined attributes),]

[constr_fk1:

foreign key (attribute_name) references referenced_table_name,]

[constr_ck1;

check( attribute_name comparison_operator constant),]

[constr_ck2:



check(attribute_name in (list of string or numeric constants),]

[constr_uq1:

unique(attribute_name)]

);

Various Domains available are;

char(n) for a string with exactly n characters

varchar(n) for a string with n or less than n characters

int for integer values

datetime for date and time related values ( ‘mm/dd/yyyy hh:mm:ss’ )

Now relation/table is created(empty initially). To populate relation with tuples use

insert into relation_name values( attribute_name1_value,

attribute_name1_value,…………………,attribute_name _value);

*put string values in single quotes

Conclusion: In this experiment concepts of various integrity constraints and DDL for creation of

new relation is studied. Using it a database is implemented actually.




Program :

Output:



Experiment No:- 3

Aim : To modify Data Definition (schema) of the database created.

1) Add column, remove column using alter table query

2) Show schema of any table(SP-help).

3) Add constraint, drop constraint explicitly(like check , unique, not null etc.)

using alter table query

Resources Used : Windows Xp professional, MY SQL.

Theory : Once the database design is finalized and database is implement actually we alter

schema of the database infrequently or never. According to changes in the requirements of the

database users we may need to change schema.

Change in database schema mainly includes addition of new attributes to existing relation schema

or deletion of the existing attributes of the relation schema. Sometimes we need to include some

addition constraints on relation or may need to remove some existing constraints

To see whether these changes are reflected in database schema we can use command SP_help

relation_name.

This command gives details of the specified relation.

Alter command is used to add column , remove column, add constraint and remove constraints.

To add new column(attribute) A to relation R

alter table R add A domaintype;

As a result of this query a new column with name A is added to relation R with null values for

existing tuples in relation R for newly added column.

To remove existing column A from relation R

alter table R drop column A;

Column A as a whole will be deleted from relation R.

To add new constraint with name C1 to relation R

alter table R add constraint C1 description_of_constraint;

To drop existing constraint C1

alter table R drop constraint C1;

Conclusion: Once designed , database schema changes infrequently. In case change is required

then we can use above DDL command to alter it.






Program:

Output:



Experiment No:- 4

Aim : To implement simple SQL queries( Single table retrieval )

� Make use of different operators (relational, logical etc)

� Selection of rows, columns, renaming columns, use of distinct keyword

� String Handling(%, - , like)

Resources Used : Windows Xp professional, MY SQL

Theory : After the database is populated with data next is data manipulation which includes

mainly retriving and modifying the data in database.

We can retrive one or more columns from relation. Also we can rename the columns in the

relation. Based on specific condition we can retrive set of rows from relation.

Basic structure of simple SQL query is.

select A1,A2,…….., An from R

where P

In select clause we list required column names. If we need all columns in relation then use just *

(i.e. select * from R where P).

In from clause we just list relation names from which we are selecting attributes mentioned in

select clause.

In where clause we mention the predicate which is tested on every tuple of relations specified in

from clause.

For generating simple predicate we use names of the attributes and the relational operators like < ,

> , =, <= , >= etc. and to generate the complex predicate we use logical operators as connective

like and , or with simple predicates.

Renaming attributes using as clause

In the select clause we can rename one or more attributes using as clause.

select A1 , A2 as new_namea3, A3,A4 as new_namea4 from R where P

Keyword distinct

distinct keyword is used to eliminate duplicate values in resultant relation

select distinct attribute_name from R

string operations using like operator

In this a pattern generated using two special characters % and _ is used with like operator



select * from employee where fname like C%

Upadating database: We can update a specific attributes value for specific or all tuples using update clause.

alter table R set fname=’jone’ where ssn=’emp0001’

for conditional update we can use case update

update R set salary=

when salary>10000 then

salary*1.06

else

salary*1.05

end

Conclusion: In this program various single table retrival queries are executed on relations of

company database. Use of various operators present is SQL is studied.




Program:

Output :



Experiment No:- 5

Aim : To write advanced queries in SQL using

Group by, having clause, aggregate functions like sum, max, min, avg, count.

Set operations like union, union all, order by clause etc.

Nested queries using not in, in, not exists, exists, any, all etc.

Resources Used : Windows Xp professional, Ms. SQL Server 2000

Theory : We can write advanced queries in SQL using the various constructs like union, order

by, not in, not exists, exists, max, min, having clause.

Union and union all operation: This operation combines the result of two or more queries into a single result set consisting of all

the rows belonging to all queries in the union.

Syntax:

Select a1, a2, a3, ……….,an from R1 union select b1, b2, b3,………,bn from R2

R1 and R2 are two compatible relations. Compatibility here means arity of both the relations is

same and also domain of ai must match with domain of bi for i=1, 2,3,……..n.

In union operation all the duplicates are eliminated and if we want to retain the duplicates the use

union all in place of union.

Order by clause: Order by clause is used to sort the tuples in given relation in either ascending or descending order

based on the value of one or more attributes present in that relation. The default order is

ascending order. If we want to sort relation in descending order use keyword desc(use keyword

asc explicitly to sort relation in ascending order ).

Syntax:

Select a1, a2, ……..,an from R order by a2 desc;

Select a1, a2, ……,an from R order by a1 [asc];

Select a1, a2,……..,an from R order by a1 asc a2 desc;

In third example tuples in R are sorted in ascding order of values of a1. If two or more tuples

have same value for a1 then the are sorted in descing order of value of a2.

Group by clause: Group by clause is used to group the rows of the relation based on a certain condition.Group by is

usually used in conjuction with the aggregate functions like sum, ag, min, max etc.

For example one can group the rows in book relation based on the authors name.

Select book_name, price, subject from book group by author.



Having clause: Having clause tells SQL to include only certain groups produced by the group by caluse in the

query result set. Having clause is equivalent to the where clause and is used to sqecity the search

criteria or search condition where group by clause is specified.

For example to select the names of the author who has written more than 3 books from book

relation.

Select author from book group by author having count(book-id) >3;

Aggregate functions: Aggregate functions are the functions that take a collection of values as input and returns a single

value. SQL offers five bullt in aggregate functions.

Average:

avg([distinct | all] n)

returns average values of n, ignoring all null values.

Minimum:

min ([distinct | all] n)

returns minimum value of n.

Maximum:

max([distinct | all] n)

returns a maximum value of n

Total:

sum([distinct | all] n)

return sum of all values of n.

count:

count([distinct | all] n)

returns the number of rowes where n is not null.

Nested subqueries:

in:

The in connective tests for the set membership, where the set is a collection of values produced by

a select clause.

For example to select details of the books written by r.p.jain and d.perry use

select book_id, book_name,price from book where author in(‘r.p.jain’, ‘d. perry’,’godse’);

not in: This connective tests for absence of the set membership.

For example to select details of the books written by authors other than r.p.jain and d.perry use

select book_id, book_name,price from book where author not in(‘r.p.jain’, ‘d. perry’,’godse’);



all:

this keyword is basically used in set comparison query.

It is used in association with relational operators.

“> all” corresponds to the phrase ‘greater than all’.

For example to display details of the book that have price greater than all the books published in

year 2000 use.

Select book_id, book_name, price from book where price >all (select price from book where

pub_year=’2000’);

any or some:

These keywords are used with relational operators in where clause of set comparison query.

“=some” is identical to in and “<>some” is identical to not in.

“>any “ is nothing but ‘greater than at least one’.

exists and not exists:

exists is the test for non empty set. It is represented by an expression of the form ‘exists (select

……. From …….) ‘. Such expression evaluates to true only if the result evaluating the sub query

represented by the (select ……. From ……) is non empty.

for example to select names of the books for which order is placed use

select book_name from book where exists( select * from order where

book.book_id=order.book_id);

not exists tests for empty set. For this the subquery must return empty set.

Conclusion: In many cases data is needed to be obtained from more than one relations based on

certain conditions that time we can use advanced queries.




Program :

Output :



Experiment No: 6

Aim: To implement Joins.

Software required: MYSQL/SQL server/Oracle

Theory:

Introduction to joins

A join can be defined as an operation that includes retrieval of data from more than one table

at a time.A join is a query that combines columns from two or more sources. Effectively you are

reversing non less decomposition process used to normalize the database pulling related data back

together in a combined result.

Technically you can only join two sources ,such as two tables.When you need to join more

sources you can do it in by joining two tables and then join the result with the the third table and

so on.

1) Inner Join: Data from multiple table is displayed after comparing values present in common

column.

Eg: select spname,custname from salesreps join customer on(salesreps.spnum =

customer.spnum)

2) Outer Join:result contains all rows from one table and matching rows from another table.

Eg: select spname,custname from salesreps left outer join customer on (salesreps.spnum =

customer.spnum)

In this query ,rows from salesreps table are returned whether or not they qualify. This is

because we specify left outer join.

The left is in reference to join and salesreps table is or left side of equality operator.Thes are

matched to NULL values for columns in right ( customer) table.

If you execute this as right outer join,difference is that unqualified rows in the right (if any)

would be returned by query.

3) Equi Join: It displays redundant columns data in result set where two or more tables are compared

for equality.

Eg:select emp.name as employeename,mgr.name as managername from employee emp

join employeemgr where emp.managerno = mgr.managerno;

Conclusion: Thus we have implemented joins in SQL and studied that join operation take two

relations and returns another relation as result. Inner join, outer join, equi join and self join are

various types of joins.






Output:



Experiment No: 7

Aim: Implementing Views

Software Required : MYSQL,ORACLE or SQL Server

Theory:

Introduction to views:

SQL introduced concept of views as a means of providing a user with a personalized model of

database.

A view can hide data that a user does not need to see.The ability of views to hide data serves

both to simplify usage because they restrict system and to hence enhance security.

Views simplify system usage because they restrict user attention to data of interest.Although a

user may be denied access to a relation that user may be allowed to access part of that relation

through a view.

Thus combination of relational level security and view-level security limits user’s access to

precisely data that user needs.

1) Creating Views:

A view can be created using create view statement.

Eg.A clerk need to know names of all customers who have a loan at each branch.This clerk is

not authorized to see information regarding specific loans that customer may have.

Create view cust_loan as

(select branch_name,customer_name

From borrower,loan

Where borrower.loan_number=loan.loan_number)

2) Altering views:

A view can be altered using alter view statement.

Eg. Update employee set target =600000 where city =’newyork’;

Select * from employee;

3) Dropping view:

A view can be dropped from database using drop view statement.

Eg. Drop view student;

Select * from student;

Table:student does not exist.

4) Modifying data through views: It is possible to modify data in base table by modyfying data in view.

Creation of view does not require resource authorization.A user who creates a vie w

does not necessarily receive all priviliges on that view.He receives only those

privileges that provide no additional authorization beyond those he already had.



Conclusion: A view is a critcal table which gives access to a subset of columnns from one

or more tables.Various operations can be performed over views like creating

views,modifying data using views,altering views and dropping views.Views are means for

security of database.




Output:



Experiment No:- 8

Aim : To design layout for forms required in the application and to study various controls in VB.

Resources Used : Windows Xp professional, MS world.

Theory : In a company database we need to create forms for all the master tables and many to

many relationship related tables.

We need to insert, delete and update, search data in these relations. So we need to create a form

which have labeled controls for various attributes of the relation .

Generally to accept input from user textbox is preferred and for predefined values listbox or

combobox is preferred

Employee form:

Employee fname: lable and textbox

Employee mname: lable and textbox

Employee lname: label and textbox

SSN : textbox

City: textbox

Salary : textbox

Department number: listbox

New : command button

Save : command button

Delete : command button

Search : command button

Display : command button

Along with these we need proper labels to describe these fields so that user will come to know in

which field which data is to be entered.

Department form

Department name: textbox

Department number: textbox

Department location:textbox

Algorithm / Activity Diagram:








Works on form

SSN: listbox

Project number :listbox

Number of hrs: textbox





Project form

Project number: textbox

Project name: textbox

Project location: textbox

Department number:listbox






A control is an object that can be frawn on a form to enhance user interaction with the application.

They respond to events initiated by the user or triggered by the system. Controls in VB are

divided in to

1) intrinsic controls;

Control description

Label Displays text on a form(read only text)

Frame Serves as a container for other controls

Checkbox Enables users to select or deselect an option

Combobox Allows users to select from a list of items or

add a new value

Hscrollbar Allows users to scroll horixontally through a

list of data in another control

Timer Lets your program perform actions in real time,

without user interaction

DirlList box Enables users to select a directory or folder

Shape Displays a shape on a form

Image Diaplays graphics on a form but cant be a

container

Picturebox Displays graphics on a form and can serve as a

container



Command button Enables users to initiate actions

Option button Lets users select one choice from a group; must

be used in groups o f tow or more

List box Enables users to select from a list items

Vscrollbar Enables users to select from a list of items

Drive list box Lets users select a disk drive

Line Displays a line on a form

Data Lets your program connect to database

File list box Lets users select a file

2) Active X controls

Control Description

MSFlexGird For displaying contents of relations on form

ADO Data control Required for database connectivity

All above controls have many properties which can be set by designer to make GUI attractive and

effective.

Among these name and caption are two important properties.

Name property take the name for control which is used in coding and caption value of control is

displayed on the form.

Conclusion: In this based on the requirements of the application form design is done. Various

fields and operations using the form are decided. Various controls available in visual basic are

studied.

Reference book:Visual Basic 6 programming Black Book

Author:Steven Holzner

Publication:Dreamtech

Program : How many forms will be there and what all fields will be there in each form is decided and

various operations to be done are also decided.

Output :

Rough sketches of the forms.



Experiment No:- 9

Aim : To implement various forms required for application using VB 6.0 applying GUI design

concepts to it , business logic development and study of various coding constructs for

applications.

Resources Used : VB 6.0, Microsoft Windows Xp professional.

Theory : A graphical user interface is a type of user interface using graphics for interaction with a

computer or other media formats which employs graphical images, widgets along with text to

represent the information and actions available to a user. Actions are performed through direct

manipulation of graphical elements(e.g clicking the command button). We must be very clear

about the colour selections, placement of graphical elements. We should take care that graphical

elements used in interface communicate correct meaning to user.

Visual basic is a true graphical development environment. It allows programmers to quickly

develop powerful Windows applications. It has the ability to develop programs that can be used a

a front end application to a database system, serving as the user interface which collects user input

and displays formatted output in a more appealing and useful form. As programmer works in the

graphical environment much of the program code is automatically generated by the Visual basic

program.

Developing applications with VB is three step approach:

1) design the appearance of the application(i.e form design by drag and drop controls in tool

box of visual basic editor)

2) assign property settings to the objects of the program

3) write code to direct specific tasks at runtime

We use Visual Basic 6.0 as event driven programming for developing code for business logic.

Actually, while programming in Visual Basic, it must first be decided how the application

interacts with the user. In other words, it must be decided how each control reacts to user actions,

such as the click of a mouse, keystrokes and so on and these reactions must be programmed. This

is called Event driven programming because the application does not determine the flow, instead,

the events caused by the user determine the flow of the application.

Various object in VB are various controls in the form. With every object some predefined events

are associated. And for every event event handler function is provided in which write code about

action to be taken for that event.

To effectively control the VB program flow we use various control statements listed below

1) If...Then...Else statement is used together with the conditional operators and logical operators.

The general format for the if...then...else statement is

If conditions Then

VB expressions

Else

VB expressions

End If

Similarly we can use nested else if.



2) Select case statement is multi way flow control statement

The general format is

Select case textexpression

Case exp1 list of vb statements

Case exp2 list of vb statements

End select

We have various looping statements in visual basic. Most commonly use are

1) for ------ next statement

General format is

For i=0 to n

Vb statements

In body of loop

Next i

2) while -----wend statement

General format is

While condition

Vb statements

In body of loop

wend

Along with all these controls we use most common built in function msgbox()

MsgBox() function.

The function displays a dialog box with a message and waits for the user

to close it by clicking on a button.

Conclusion: All forms are designed with required fields and relevant properties of control fields

are set.



Publication:Dreamtech



Program :

Go to start menu

Select programs

Select Microsoft visual studio

Select Microsoft visual basic 6.0

Editor will be opened

Which will have tool box on the leftmost side

Properties , project explorer, layout windows on rightmost side

Just drag and drop desire controls from tool box and set properties in properties window(mainly

caption and name properties of every control)

Output : e.g employee form

Similarly all other forms can be designed



Experiment No:- 10

Aim : To establish the SQL server 2000 and VB 6.0 connectivity through ADO.

Resources Used : VB 6.0, Microsoft Windows Xp professional Ms SQL server 2000.

Theory : ADO is the object-based interface that provides a logical set of objects that can be accessed

from code.These objects are:

Connection : Establishes the connection with the data base.

Property:

connectionstring Valuse of these property is string specifying loction of the database.

Methods: Open( ) : used to open connection with database(if path is passed as parameter and if connection

string property is set then all paramerer to open are optional)

Close() : used to close connection opened by open method

Execute() : executes query on database and returns recordset object.

Command. Defines the commands that will be executed against the database.

Recordset. Contains the data that is retrieved from the database.

EOF and BOF are only propertyies of recordset object used to check whthere recordset is empty

or not.

These objects present an interface in the form of properties and methods that can be

queried and manipulated. ADO was specifically developed to be small, lightweight, fast and

feature

complete . for the database applications or for the Internet.

An important thing in ADO is that the objects in this model are not dependant on one

another. This means that one can create instances of objects independent of one another, for

example, one can create a Recordset object without creating a connection object.

Unlike the older technologies, ADO is more flexible, ADO code is easier to write, read and

maintain. ADO is built on top of OLE DB and is capable of accessing any sort of data that is

wrapped

and exposed by an appropriate OLE DB provider.



Conclusion: There are many techniques for connecting database with front end. In this

experiment SQL server 2000 connectivity using V B 6.0 ADO is studied



Publication: Dreamtech

Program :

Create system DSN

Go to control panal � administrative tools� ODBC data sources� select system dsn tab�click

add �Select driver (SQL server)�finish� write dsn name and server name -� click next �

click next�change default database to your database name-� click next �finish �test data

source � tested successfully� ok �ok �ok

Design GUI

Now in VB design form and drag and drop ADODC control on it. If control is not available in the

tool box then press ctrl + T to display component box and click in text box Microsoft Ado data

control 6.0(OLE DB) to add it to tool box.

In the properties window of the ADODC control click connectionstring property and build it.

For every control that is displaying data retrived from relation set datasource and datafield

property correctly.

Output :

g u i stud

Documents

customer entity

employee entity

entity relationship

specific entity

properties of entity

attribute age

particular entity

type of attribute