1. What is Marshaling?

Ans: The process of packing and sending interface parameters across process boundaries.

2. What is the default data type in VB?

Ans: the default datatype in VB is variant.

3. What are the record set types?

Ans: RdOpenFowardOnly 0 (Default used only for the read only purpose)
RdOpenStatic 1
RdOpenDynamic 2
RdOpenKeySet 3 (Normally used for the live project)

4. What is bulk binding ?

Ans: The assigning of values to PL/SQL variables in SQL statements is called binding. The binding of an entire collection at once is called bulk binding. Bulk binds improve performance by minimizing the number of context switches between the PL/SQL and SQL engines. Typically, using bulk binds improves performance for SQL statements that affect four or more database rows. The more rows affected by a SQL statement, the greater the performance gain from bulk binds.

5. How do we call MS- Excel in VB?

Ans: after selecting Microsoft excel library in refrence section we can create object for excel by CreateObject ("Excel.Application")

6. What is Mixed Cursors?

Ans: A mixed cursor is a combination of a keyset-driven cursor and a dynamic cursor. It is used when the result set is too large to reasonably save keys for the entire result set. Mixed cursors are implemented by creating a keyset that is smaller than the entire result set but larger than the rowset.
As long as the application scrolls within the keyset, the behavior is keyset-driven. When the application scrolls outside the keyset, the behavior is dynamic: The cursor fetches the requested rows and creates a new keyset. After the new keyset is created, the behavior reverts to keyset-driven within that keyset.

7. What does option Explicit means?

Ans: All the variable which are used witing the program need to be declared when you use this option

8. What is difference between sub query and co-query?

Ans: Sub-query is an inner query that returns a result used by another outer query may be by means of an IN operator like the following:
select * from [dbo].[Orders] where [Customer_ID] IN (select Customer_ID from [dbo].[Customer] where [City]='Kolkata')
A Co-query is a part of a UNION query.
A subquery can also be used with = operator; but in that case it must have to be guaranteed that it will return only one row of result

9. What is the diff between RDO and ADO?

Ans: RDO is Hierarchy model where as ADO is Object model. ADO can access data from both flat files as well as the data bases.I.e., It is encapsulation of DAO, RDO, OLE that is why we call it as OLE-DB Technology.

10. Max how many controls can be used in a single form...

Ans: 256 controls.

11. What is Option Implicit?

Ans: Option Explicit has 2 values ON and OFF deafult value is ON -Option Explicit means - All the variables should be declared before its use. Else it shows error..it is a good practice to use this.

12. How can you save and Get data from Clipboard

Ans: Using clipboard.setdata and clipboard.getdata methods

13. What is Marshaling?

Ans: The process of packing and sending interface parameters across process boundaries.

14. Difference between DDE and OLE.

Ans: DDE (Dynamic Data Exchange), a communication protocol that let applications call each other.OLE was the first protocol that enabled users and programmers to create compound documents—that is, documents that contain data from different applications (for example, an Excel worksheet inside a Word document). Depending on the application's needs, compound documents can completely encapsulate other simpler documents (embedding) or contain simply a reference to existing documents (linking). When the user clicks on an embedded or linked document inside a compound document, Windows runs the application that's capable of dealing with that particular type of document.

15. What is a property bag?

Ans: A Property Bag object holds information that is to be saved and restored across invocations of an object.

16. What is the difference between Object and Class?

Ans: Class is a Template 
Object is an Instance of a Class

17. What is Seek Method which type of record set is available this?

Ans: Only in DbOpenTables.
Syntax: rs.index = “empno”
rs.seek “=” ,
10 If with our setting the rs.index then run time error will occur.

18. Difference between Class Module and Standard Module?

Ans: Standard Module: Properties, methods and variable declare in this module can be accessed throughout the application.
Class Module: Properties,Methods and variables declare in the class module can be accessed only after creating the object of the class. after creating the object you can access these properties and method from any applications