Technology Questions

The ServiceInstaller class, also known as the project installer class, is used to install a Windows service.

PL/SQL is Procedural Language SQL that is an extension of SQL that results in a more structural language composed of blocks. It is mainly used in writing applications that needs to be structured and has error handling.

XML templates are XML files such as XHTML files. XML templates includes the processing directives which affect how the template is rendered, and the template expressions which are substituted dynamically by various data.

If constructor opens the file 

finalize() method closes that file.

If constructor opens the connection 

finalize() method closes that connection.

To perform finalization operation we must overriding finalize method.

boolean isDirectory();

The following are the usages of the Command object in AD0.NET:

The Command object in AD0.NET executes a command against the database and retrieves a DataReader or DataSet object.

  =>  It also executes the INSERT, UPDATE, or DELETE command against the database.
  =>  All the command objects are derived from the DbCommand class.
  =>  The command object is represented by two classes: SqlCommand and OleDbCommand.
  =>  The Command object provides three methods to execute commands on the database:
  =>  The ExecuteNonQuery() method executes the commands and does not return any value.
  =>  The ExecuteScalar() method returns a single value from a database query.
  =>  The ExecuteReader() method returns a result set by using the DataReader object.

1. Operational Data Store has very low data latency. Data moved to ODS mostly on event based rather than time based ETL to Data Warehouse/Data Mart. 

2. ODS is more closer to OLTP system. We don't normally prefer to store aggregated data in OLTP. So it is with ODS. 

3. Unlike data warehouse where data is HISTORICAL, ODS is near real time(NRT). So data aggregation is less important is ODS as data keeps changing.

COMMIT statements are used to release locks which are required for that unit of work, and then permit a new unit of work. In other words, if COMMITS are not coded in the program and the program has been sent for execution, then while processing, in place of just going back to a few inserts since the nearest commit, the program has to go back to the inserts which were made during the entire run of the program. This extra process takes around twice or thrice the time taken normally.