Technology Questions

There are three ways that can be used in order for a Thread to be created:

A class may extend the Thread class.

A class may implement the Runnable interface.

An application can use the Executor framework, in order to create a thread pool.

The Runnable interface is preferred, as it does not require an object to inherit the Thread class. In case your application design requires multiple inheritance, only interfaces can help you. Also, the thread pool is very efficient and can be implemented and used very easily.

- Online backup is one which is taken at the time the database is running in the ARCHIVELOG mode.

- Following files should be backed up during the Offline Backup: All data file, all control file and all online redo log file. But in the case of the online backup following files is backed up: All data files all archived redo log files and one control file via the alter database command.

- Offline database we cannot rely upon but in case of online database no issues.

- Offline backup no archived mode is required but in the online backup it is must.

ADO.NET is a very important feature of .NET Framework, which is used to work with data that is stored in structured data sources, such as databases and XML files. The following are some of the important features of ADO.NET:

 =>   Contains a number of classes that provide you with various methods and attributes to manage the communication between your application and data source.

 =>   Enables you to access different data sources, such as Microsoft SQL Server, and XML, as per your requirements.

 =>   Provides a rich set of features, such as connection and commands that can be used to develop robust and highly efficient data services in .NET applications.

 =>   Provides various data providers that are specific to databases produced by various vendors. For example, ADO.NET has a separate provider to access data from Oracle databases; whereas, another provider is used to access data from SQL databases.

Row Level Trigger :
Row Level Trigger is fired each time row is affected by Insert, Update or Delete command. If statement doesn’t affect any row, no trigger action happens.

Statement Level Trigger :
This kind of trigger fires when a SQL statement affects the rows of the table. The trigger activates and performs its activity irrespective of number of rows affected due to SQL statement.

A delegate declares a ref type that references a named of anonymous method. Delegates are secure and type-safe.

Scope resolution operator allows a program to reference an identifier in the global scope that is hidden by another identifier with the same name in the local scope.