Powerbuilder Interview Questions Part 3

121

Ans.

Can you inherit datawindow objects? 

We can not directly inherited the datawindow object but indirectly we can do that by using user Object.

122

Ans.

What is the purpose of using user objects?

For the memory Management and applying oops concepts.

123

Ans.

When does item focus change event fires?

Occurs when the current item in the control changes.

124

Ans.

When does itemerror event triggers?

Occurs when a field has been modified, the field loses focus (for example, the user presses enter, tab, or an arrow key or clicks the mouse on another field in the DataWindow), and the data in the field does not pass the validation rules for its column. ItemError can also occur when a value imported into a DataWindow control or DataStore does not pass the validation rules for its column.

125

What are the methods of software engineering?

126

Ans.

What are the steps in SDLC?

WaterFall

Conception

Initiation

Analysis

Design

Coding

Testing

Implementation.

127

Ans.

What are the different types of testing?

Basically there are four type of testing

Unit testing – done by programmer

Integration testing – when all the module get integrated.

System testing –

User level testing –

Top down testing ,bottom up testing, black box testing, white box testing.

128

What is paroto diegram?

129

How can you estimate the time required finishing one job?

130

Ans.

What values any sql will return?

Sqlcode –

Sqlnrows –

Sqlerrtext –

131

Ans.

If you do not write commit then what will happen?

When you write the commit statement then only dada is permanently stored in database. When you close the ORACLE session the oracle automatically committed the data that is in buffer.

132

Ans.

Can you inherit user object?

Yes.

133

What are the parameters in retrievestart, retrieveend, and retrieverow events?

134

Ans.

What will happen if we delete rows from a datawindow whose update property is false?

These deleted rows will not go to the delete buffer it will work as rowsdescard function.

135

Ans.

How can you move rows from one datawindow to other and datawindow to buffer?

Rowsmove()

136

What are the difference between sybase and oracle?

137

What is thick and thin database structure?

138

What is for resetupdate function is used?

139

Ans.

What is dde?

Dynamic data exchange.

140

Ans.

What all functions fire on calling update function?

Updates the database with the changes made in a DataWindow control or DataStore. Update can also call AcceptText for the current row and column before it updates the database.

dwcontrol.Update ( { accept {, resetflag } } )

Argument Description

Dwcontrol  The name of the DataWindow control, DataStore, or child DataWindow that contains the information you want to use to update the database

accept (optional)  A boolean value specifying whether the DataWindow control or DataStore should automatically perform an AcceptText prior to performing the update:

¨TRUE — (Default) Perform AcceptText. The update is canceled if the data fails validation¨         

FALSE — Do not perform AcceptText

resetflag (optional) A boolean value specifying whether dwcontrol should automatically reset the update flags:

¨TRUE — (Default) Reset the flags¨       

FALSE — Do not reset the flags

Return:

Integer. Returns 1 if it succeeds and -1 if an error occurs. If any argument’s value is NULL, Update returns NULL.

Update may trigger these events:

DBError

SQLPreview

UpdateEnd

UpdateStart

If AcceptText is performed, it may trigger these events:

ItemChanged

ItemError

141

What is encapsulation, inheritance, polymorphism & give at least one example of each one of them?

142

Ans.

What the describe will return if you do not pass any  expression?

String. Returns a string that includes a value for each property or Evaluate function. A newline character (~n) separates the value of each item in property list.

If the property list contains an invalid item, Describe returns an exclamation point (!) for that item and ignores the rest of the property list. Describe returns a question mark (?) if there is no value for a property.

When the value of a property contains a question mark (?), the value is returned in quotes so that you can distinguish between it and a property with no value.

If any argument’s value is NULL, Describe returns NULL.

143

Ans.

Can you open multiple response windows at the same time?

No, When the one Response window get close then only second window is open.

144

What are the registry related functions provided with pb?

145

Ans.

What is the difference between settrans and settransobject?

In most cases, use the SetTransObject function to specify the transaction object. It is more efficient and allows you to control when changes to the database get committed.

SetTrans copies the values from a specified transaction object to the internal transaction object for the DataWindow control or DataStore. When you use SetTrans in a script, the DataWindow uses its internal transaction object and automatically connects and disconnects as needed; any errors that occur cause an automatic rollback. With SetTrans, you do not specify SQL statements, such as CONNECT, COMMIT, and DISCONNECT. The DataWindow control connects and disconnects after each Retrieve or Update function.

Use SetTrans when you want PowerBuilder to manage the database connections automatically because you have a limited number of available connections or will be use the application from a remote location. SetTrans is appropriate when you are only retrieving data and do not need to hold database locks on records the user is modifying. However, for better performance, you should use SetTransObject.

146

How can you call the external function from dll?

147

What all application services provided with the pfc?

148

What all window services provided with the pfc?

149

What all are the datawindow services provides with the pfc?

150

How many layers of pbls are in pfc and what they are?

151

What is deligation?

152

What is the difference between operator overloading and polymorphism?

153

Write down query to find out duplicate rows?

154

If four records with same data in all column are there how can you delete two of it in oracle?

155

What all tables get updated when you create a procedure?

156

Ans.

What is the advantage of the procedure?

Procedure is stored in database. So it is faster than any other Query.

157

Ans.

Where can you get the definition of sp in oracle?

There is a one table from which we can get the definition of SP.

158

In joins and subquery which one is preferable and why?

159

Can you have the script of any function in ancestor in the descendent object function? If not how can you get it?

160

Ans.

What is yield function?

Yields control to other graphic objects, including objects that are not PowerBuilder objects. Yield checks the message queue and if there are messages in the queue, it pulls them from the queue.

Return value

Boolean. Returns TRUE if it pulls messages from the message queue and FALSE if there are no messages.

Usage

Include Yield within a loop so that other processes can happen. For example, use Yield to allow end users to interrupt a loop. By yielding control, you allow the user time to click on a cancel button in another window. Then code in the loop can check whether a global variable’s status has changed. You can also use Yield in a loop in which you are waiting for something to finish so that other processing can take place, in either your or some other application.

161

What is the cluster and non cluster index in Sybase?

162

What is the cluster in oracle?

163

What is the sequence and what is the use of it in oracle?

164

What will happen if I call one event in other and other in first event?

165

Why we should write cursor in sp not directly?

166

What is the exception and error handeling?

167

What is the function of setredraw function?

Controls the automatic redrawing of an object or control after each change to its properties.

Objectname.SetRedraw ( boolean )

Argument Description

Objectname      The name of the object or control for which you wants to change the redraw setting. Objectname can be a child DataWindow, but cannot be a menu.

Boolean A boolean value that controls whether PowerBuilder redraws an object automatically after a change.    

Values are:

¨TRUE — Automatically redraw the object or control after each change to its properties¨  

FALSE — Do not redraw after each change

Return value

Integer. Returns 1 if it succeeds and -1 if an error occurs. If boolean is NULL, SetRedraw returns NULL.

168

How can we get column modified?

169

Can you open response window using opensheet function if yes what will happen?

170

What are the functions to set and get garbage collection time limit?

171

What is for setforegroundwindow is used?

172

Ans.

What for setformat function used?

Specifies a display format for a column in a DataWindow control or DataStore.

DataWindow controls, DataStore objects, and child DataWindows

Syntax

dwcontrol.SetFormat ( column, format )

Argument Description

Dwcontrol        The name of the DataWindow control, DataStore, or child DataWindow in which you want to specify the display format

Column : The column for which you are specifying the display format.  Column can be a column number (integer) or a column name (string)

Format : A string whose value is the display format for the DataWindow column

Return value

Integer. Returns 1 if it succeeds and -1 if an error occurs. If any argument’s value is NULL, SetFormat returns NULL. The return value is usually not used.

173

What is the pixeltounits function?

174

Ans.

How can we get the environment?

Gets information about the operating system, processor, and screen display of the system.

GetEnvironment ( environmentinfo )

Argument Description

Environmentinfo The name of the Environment object that will hold the information about the environment

Return value

Integer. Returns 1 if it succeeds and -1 if an error occurs. If environmentinfo is NULL, GetEnvironment returns NULL

175

What events get fire on calling update functions.and what are the parameter in update function?

176

What values we can send with open with param?

177

Ans.

When does idle event fire?

Occurs when the Idle function has been called in an application object script and the specified number of seconds has elapsed with no mouse or keyboard activity.

178

Ans.

When does systemerror event fire?

Occurs when a serious execution time error occurs (such as trying to open a nonexistent window).

179

What are the connection begin and connection end event?

180

Ans.

What does classname function return?

Provides the class (or name) of the specified object.

controlname.Classname ( )

Argument          Description

Controlname    The name of the control for which you want to know the name assigned to the control in the style window (the class of the control)

Return value

String. Returns the class of controlname, the name assigned to the control. Returns the empty string (“”) if an error occurs. If controlname is NULL, ClassName returns NULL.