Technology Questions

Overloading allows multiple functions to exist with same name but different parameters. Again if you take bike as an example, it has a function “Start” with two forms i.e. ’Auto Start’ and ’kick start’.

Trigger allows us to execute a batch of SQL code when an insert, update or delete command is executed against a specific table.

Triggers are special types of stored procedures that are defined to execute automatically in place of or after data modifications. They can be executed automatically on the insert, delete and update operation.

Yes the object is retained. It creates a timer that calls a selector on the current threads run loop. It may not be 100% precise time-wise as it attempts to dequeue the message from the run loop and perform the selector.

The window.history object can be written without the window prefix.
To protect the privacy of the users, there are limitations to how JavaScript can access this object.
Some methods:

    history.back() - same as clicking back in the browser
    history.forward() - same as clicking forward in the browser

Marshalling is the process of gathering data from one or more applications or non-contiguous sources in computer storage, putting the data pieces into a message buffer, and organizing or converting the data into a format that is prescribed for a particular receiver or programming interface.  

An alert box displays only one button which is the OK button whereas the Confirm box displays two buttons namely OK and cancel.

Advantages of 3G:

- Overcrowding is relieved in existing systems with radio spectrum
- Bandwidth, security and reliability are more
- Provides interoperability among service providers
- Availability of fixed and variable rates
- Support to devices with backward compatibility with existing networks
- Always online devices – 3G uses IP connectivity which is packet based
- Rich multi media services are available

Disadvantages of 3G:

- The cost of cellular infrastructure , upgrading base stations is very high
- Needs different handsets.
- Roaming and data/voice work together has not yet been implemented
- Power consumption is high
- Requires closer base stations and are expensive
- Spectrum-license costs, network deployment costs and handset subsidies subscribers are tremendous.

Retain -Specifies that retain should be invoked on the object upon assignment. takes ownership of an object

Assign - Specifies that the setter uses simple assignment. Uses on attribute of scalar type like float,int.