Visual Basic 6 Interview Questions and Answers
Question - 41 : - What are the locks available in Visual Basic?
Answer - 41 : - Locking is the process by which a DBMS restricts access to a row in a multi-user environment 4 types of locks. They are
1. Batch Optimistic
2. Optimistic
3. Pessimistic
4. ReadOnly
Operations in a relational database act on a complete set of rows. The set of rows returned by a SELECT statement consists of all the rows that satisfy the conditions in the WHERE clause of the statement. This complete set of rows returned by the statement is known as the result set.
Applications, especially those that are interactive and online, cannot always work effectively with the entire result set as a unit.
These applications need a mechanism to work with one row or a small block of rows at a time. Cursors are an extension to result sets that provide that mechanism.
Cursor or lock type Advantages Disadvantages AdOpenForwardOnly (Default) Low resource requirements Cannot scroll backward No data concurrency AdOpenStatic Scrollable (Wont detect changes made at the same time by another application) No data concurrency AdOpenKeyset Some data concurrency Scrollable Higher resource requirements Not available in disconnected scenario AdOpenDynamic High data concurrency Scrollable Highest resource requirements Not available in disconnected scenario AdLockReadOnly Low resource requirements Highly scalable Data not updatable through cursor AdLockBatchOptimistic Batch updates Allows disconnected scenarios Other users able to access data Data can be changed by multiple users at once AdLockPessimistic Data cannot be changed by other users while locked Prevents other users from accessing data while locked AdLockOptimistic Other users able to access data Data can be changed by multiple users at once
Question - 42 : - Diff type of Datatypes?
Answer - 42 : - LOB (Large Object Data type).
CLOB (Stores Character Objects).
BLOB ( Store Binary Objects such as Graphic, Video Chips and Sound files).
BFILE(Store file pointers to LOB It may Contain filename for photo’s store on CD_ROM).
Question - 43 : - What is Tabstrip control?
Answer - 43 : - Libraries of procedure external to the application but can be called from the application.
Question - 44 : - What is Static Variable?
Answer - 44 : - Its Scope will be available through out the life time.
Question - 45 : - What is DBSqlPassThrough?
Answer - 45 : - It will By Passing the Jet Query Processor.
Question - 46 : - What is the starting Index value? How to locate it?
Answer - 46 : - It is tab control to place our controls with in the form in multiple sheets.
Index starts with 1.
And to identify If Tabstrip1.SelectedItem.
Index = 1 Then ..
End if
Question - 47 : - What is Parser Bug?
Answer - 47 : - It is difficult to use database objects declared in a module from within a form.
Question - 48 : - What is keyword used to compare to objects?
Answer - 48 : - ISOperator Returns Boolean.
Question - 49 : - Suppose from form1 to form2 object property settings will arise to ?
Answer - 49 : - Invalid procedure call or argument (Run time error 5)
Question - 50 : - What is Static Variable?
Answer - 50 : - Its Scope will be available through out the life time.