Technology Questions

-  The process of having a copy of redo log files is called mirroring.
-  It is done by creating group of log files together. This ensures that LGWR automatically writes them to all the members of the current on-line redo log group.
-  In case a group fails, the database automatically switches over to the next group. It diminishes the performance.

- Create a template that designs a layout for your application.

- Create the composing pages.

- Create a definition which means that suppose that you configured Tiles, in web.xml, to startup using the TilesServlet, we need to specify which files will contain the Tiles definitions to load.

- Render the definition.

- Physical Data Integration is all about creating new system that replicates data from the source systems.

- This process is done to manage the data independent of the original system.

- Data Warehouse is the example of Physical Data Integration.

- The benefits of PDI include data version management, combination of data from various sources, like mainframes, flat files, databases.

- A separate system is needed for handling vast data volumes.

Data cleaning is also known as data scrubbing. Data cleaning is a process which ensures the set of data is correct and accurate. Data accuracy and consistency, data integration is checked during data cleaning. Data cleaning can be applied for a set of records or multiple sets of data which need to be merged.

Data cleaning is performed by reading all records in a set and verifying their accuracy. Typos and spelling errors are rectified. Mislabeled data if available is labeled and filed. Incomplete or missing entries are completed. Unrecoverable records are purged, for not to take space and inefficient operations.

RegularExpressionValidator checks if entered data matches a specific format

Cache events are processed only when the Postback events occur

The primary keys of entity tables are the foreign keys of dimension tables.

The Primary keys of fact dimensional table are the foreign keys of fact tablels.

Oracle check constraint is used to ensure that before inserting the data in the database, it is validated and checked for the condition.
Example:
Below, the constraint is that the id has to be between 0 and 1000.
create table employee ( id number check (id between 0 and 1000), Name varchar(200) );