Posted Under ADO.NET Interview Questions
Difference between SqlCommand and SqlCommandBuilder?
a) SQLCommand is used to execute all kind of SQL queries like DML(Insert, update,Delete) & DDL like(Create table, drop table etc)
b)SQLCommandBuilder object is used to build & execute SQL (DML) queries like select, insert, update & delete.
Why can not we use Multiple inheritance and garbage collector paralelly in .net?
.net doesn't support the mutiple inheritance, perhaps you may talk about multi-level inheritance.
In the later case, if a class is inherited from another class, at the time of creating instance, it will obviously give a call to its base class constructor (ie bottom - top approach). Like wise the constructor execution is takes place in top down approach (ie. base class constructor is executed and the derived class constructor is executed).
So for GC, it will collect only when an object does not have any reference. As we see previously, the derived is constructed based on base class. There is a reference is set to be. Obviously GC cannot be collected.
How to find the given query is optimised one or not?
First Excute Sql Quries in Query Analzer,see How much time 2 take Excute , if Less then the ur desired Time, then it will Optimize query
How to copy the contents from one table to another table and how to delete the source table in ado.net?
it is possible
Datatable dt = ds.Tables.copy();
//now the structure and data are copied into 'dt'
//now the source is removed from the 'ds'
How to call the SQL commands asynchronously in ADO.NET version 2.0?
these comes with Begin and End like Beginexecutescalr() Endexecutescalar().......by using these command we can achieve asynch comm in ado.net
What is typed and untyped dataset?
A DataSet can be Typed or Untyped. The difference between the two lies in the fact that a Typed DataSet has a schema and an Untyped DataSet does not have one. It should be noted that the Typed Datasets have more support in Visual studio.
I loaded the dataset with a table of 10 records. One of the records is deleted from the backend, How do you check whether all the 10 records were present while updating the
data(Which event and steps) and throw the exception.
By Using the Transactions we can check the Exact Numbers of the rows to be updated and if the updation fails then the Transaction will be rollbacked.
Can dataReader hold data from multiple tables?
Data reader can hold data from multiple tables and datareader can hold more than one table.
string query="select * from employee; select * from student";
sqlcommand cmd=new sqlcommand(query, connection);
What is different between SqlCommand object and Command Behavior Object?
DO.NET Command Object - The Command object is similar to the old ADO command object.
It is used to store SQL statements that need to be executed against a data source.
The Command object can execute SELECT statements, INSERT, UPDATE, or DELETE statements, stored procedures, or any other statement understood by the database.
What is bubbled event can u pls explain?
All heavy controls like grid view,datagrid or datalist,repeater controls cantains the chield controls like button or link button, when we click this button then the event will be raised, that events are handled by parant controls,that is called event bubbling,means event is bubbled from bottom(chield)to up(parant).
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