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Q103. What is the function of rptFunction control?

Q104. What is data report? Write the steps to create a data report

based on a query on a database?

Data reporting is key elements relating to an organization's performance in order

to improve different aspects. Data reporting measures performance, and

analyzes other key elements that can then be shared within the organization or

with the public.

Visual Basic 6 provides you with a data report designer to create your report.

The data report designer has its own set of controls which allow you to customize

your report seamlessly. The steps in creating the report in VB6 are listed below:

Step 1: Adding Data Report

Start Visual Basic as a Standard EXE project. From the Project menu in the VBE,

select Add Data Report in the dropdown menu. Now, you will be presented with

the data report environment. The data report environment contains 6 controls,

they are RptTextBox, RptLine, RptFunction, RptLabel, RptImage and RptShape.

You can customize your report here by adding a title to the page header using

the report label RptLabel. Simply drag and draw the RptLabel control on the data

report designer window and use the Caption property to change the text that

should be displayed. You can also add graphics to the report using the RptImage

control.

Step 2: Connecting the report to database using Data Environment Designer

Click the Project menu, then select Data Environment. from the drop-down

menu. The default data environment will appear. Now, to connect to the

database, right-click connection1 and select Microsoft Jet 4 OLE DB Provider

from the Data Link Properties dialog, then click next. Now, you need to connect

to the database by selecting a database file from your hard disk.

Step 3: Retrieving Information from the Database

In order to use the database in our report, we need to create query to retrieve

the information from the database. Here, we will use SQL command to create the

query. First of all, right click on MyConnection to add a command to the data

environment. The default command is Command1. In order to use SQL

command, right-click Command1 and we can see its properties dialog. At the

General tab, select SQL statement and key in the following SQL statement:

SELECT [field name1, field name2]

FROM Table1 ORDER BY []

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This command is to select all the field1 and field2 from the table1 in the

database. The command ORDER BY [..] is to arrange the list in ascending order

according to the [..].

Now, we need to customize a few properties of our data report so that it can

connect to the database. The first property to set is the DataSource, set it toDataEnvironment. Next, we need to set the DataMember property to Command1.

To add data to our report, we need to drag the fields from Command1 in

DataEnvironment into DataReport. Visual Basic 6 will automatically draw a

RptTextBox, along with a RptLabel control for each field on the report. We can

customize the look of the labels as well as the TextBoxes from the properties

window of DataReport.

Q105. What is ADODC and difference with ADODB?

The Data control comes embedded into VB, just like the text box. It allows us toquickly and easily create a program for creating and using databases. The ADO

Data Control uses ADO to quickly create connection between data bound

controls and data providers. Data-bound controls are any controls that feature a

DataSource property. Data providers can be any source written to OLEDB

specification. We can also easily create our own data provider using Visual

Basics class module. We can add an ADO data control to a form like any other

control.

Sl.No. ADODC ADODB

1 ADODC is an ActiveX control. ADODB is a ActiveX DLL.

2 It is suitable for small project. It is suitable for big software.

3 It is just for making connection easily and to navigate through the data.

ADODB is much more like transaction handling and more command over

connection and recordset object.

Q106. Explain different string functions in VB.

Sl. No Function Syntax Description

1 Len----Len(string)-------Returns a Long containing the length of the

specified string.

Example: lngLen = Len("Visual Basic") ' lngLen = 12

2 Mid$ (or Mid)----Mid$(string, start[, length])------Returns a substring

containing a specified number of characters from a string.

Example: strSubstr = Mid$("Visual Basic", 3, 4) ' strSubstr = "sual"

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3 Left$ (or Left)-----Left$(string, length)-----Returns a substring containing a

specified number of characters from the beginning (left side) of a string.

Example: strSubstr = Left$("Visual Basic", 3) ' strSubstr = "Vis"

4 UCase$ (or UCase)------UCase$(string)------Converts all lowercase letters ina string to uppercase. Any existing uppercase letters and non-alpha characters

remain unchanged.

Example: strNew = UCase$("Visual Basic") ' strNew = "VISUAL BASIC"

5 Instr------InStr([start,] string1, string2 [, compare])-----Returns a Long

specifying the position of one string within another. The search starts either at

the first character position or at the position specified by the start argument, and

proceeds forward toward the end of the string (stopping when either string2 is

found or when the end of the string1 is reached).

Examples: lngPos = Instr("Visual Basic", "a")

lngPos = 5

lngPos = Instr(6, "Visual Basic", "a")

lngPos = 9 (starting at position 6)

lngPos = Instr("Visual Basic", "A")

lngPos = 0 (case-sensitive search)

6 Space$ (or Space)------Space$(number)--------Returns a string containing

the specified number of blank spaces.

Examples: strTest = Space$(5) ' strTest = " "

7 String$ (or String)-------String$(number, character)-------Returns a string

containing a repeating character string of the length specified.

Examples: strTest = String$(5, "a")

' strTest = "aaaaa"

strTest = String$(5, 97)

' strTest = "aaaaa" (97 is the ASCII code for "a")

8 Replace$ (or Replace)-------Replace$(expression, find, replacewith[, start[,

count[, compare]]])------Returns a string in which a specified substring has been

replaced with another substring a specified number of times.

Examples: strNewDate = Replace$("08/31/2001", "/", "-")

strNewDate = "08-31-2001"

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9 StrReverse$ (or StrReverse)------StrReverse$(string)-------Returns a string

in which the character order of a specified string is reversed.

Examples: strTest = StrReverse$("Visual Basic") strTest = "cisaBlausiV"

10 LTrim$ (or LTrim) LTrim$(string) Removes leading blank spacesfrom a string.

Examples: strTest = LTrim$(" Visual Basic ")

strTest = "Visual Basic "

11 RTrim$ (or RTrim) RTrim$(string) Removes trailing blank spaces from

a string.

Examples: strTest = RTrim$("Visual Basic") ' strTest = "Visual Basic"

12 Chr$ (or Chr)------Chr$(charcode)-------Returns a string containing thecharacter associated with the specified character code.

Examples: strChar = Chr$(65) ' strChar = "A"

13 Asc------Asc(string)------Returns an Integer representing the ASCII character

code corresponding to the first letter in a string.

Examples: intCode = Asc("*") ' intCode = 42

intCode = Asc("ABC") ' intCode = 65

Q107. Explain how ADO itself connect to a database.

There are various ways to access a database in VB6 such as DAO or ADO. ADO

stands for ActiveX Data Objects, while DAO is Data Access Object. To access a

database via ADO, you need to follow several steps: creating an ADO connection

to a database, opening the database connection, creating an ADO record set,

opening the record set, obtaining data from the record set and closing the record

set. VB6 also provides an ADO data control, which saves developers a lot of time

while developing database applications. With the ADO data control tool, you can

easily deploy database connection within your VB applications.

Q108. Describe ADO object model.

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ADO is a set of objects that allow programmers to code te logic from languages

like VB6. ADO provides two objects for managing connections with data sources

(Connection and Command), two objects for managing the data returned froma data source (Field and Recordset) and three secondary objects

(Parameters, Properties, and Errors) for managing information about ADO.

ADO provides a quick, easy way to access data from a variety of development

environments.

Command Object

It defines a specific command to execute against a data source. The Command

object represents a SQL statement or stored procedure that software executes

against the data source. Use of Command objects is optional -- data can beextracted directly from a Connection object, if desired.

Connection Object

It represents an open connection to a data source. The Connection object sets

up a link between your program and the data source. This object contains all of

the necessary configuration information and acts as a gateway for all of the

other ADO objects. The Connection object is mandatory -- all implementations of

ADO must support it.

Recordset Object

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It represents the entire set of records from a database table or the results of an

executed command. Each command execution results in a Recordset containing

the results of the query. This object is a mandatory part of ADO.

Field Object

It represents a column of data with a common data type. Each Recordset object

is composed of a number ofField objects that represent individual columns in

the Recordset. This object is a mandatory feature of ADO.

Parameter Object

It represents a parameter or argument associated with a Command object

based on a parameterized query or stored procedure.Command objects may

have an associated collection ofParameter objects that provide additional

information to the data source when executing the command. The Parameter

collection is optional.

Error Object

It provides specific details about each ADO error. The Error object represents an

error encountered by the ADO objects, especially on the data provider.

Property Object

It represents a dynamic characteristic of an ADO object that is defined by the

provider. This object is not currently supported on UNIX.

Q109. Explain if-then-else statement.

To effectively control the VB program flow, we shall use If...Then...Else statement

together with the conditional operators and logical operators.

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

If conditions ThenVB expressionsElse

VB expressionsEnd If

* any If..Then..Else statement must end with End If. Sometime it is not necessary

to use Else.

Example:

Private Sub OK_Click()

firstnum=Val(usernum1.Text

secondnum=Val(usernum2.Text)

If total=firstnum+secondnum And Val(sum.Text)0 Then

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correct.Visible = True

wrong.Visible = False

Else

correct.Visible = False

wrong.Visible = True

End IfEnd Sub

Q110. Explain looping statements in VB6.

Do Loop

a) Do While condition

Block of one or more VB statements

Loop

b) Do

Block of one or more VB statements

Loop While condition

c) Do Until condition

Block of one or more VB statements

Loop

d) Do

Block of one or more VB statements

Loop Until condition

e) For....Next Loop

The format is:

For counter=startNumber to endNumber (Step increment)

One or more VB statements

Next