Technology Questions

The mysqli extension , or as it is sometimes known, the MYSQL improved extension ,was developed to take advantage of new features found in MYSQL systems versions 4.1.3 and later.

The mysqli extension has a number of benfits,the key enhancements over the mysql extension being:
=> Object-oriented interface
=> Support for prepared statements
=> Support for multiple statements
=> Support for transactions
=> Enhanced debugging capabilities
=> Embedded server support

In a baseband transmission, the entire bandwidth of the cable is consumed by a single signal. In broadband

transmission, signals are sent on multiple frequencies, allowing multiple signals to be sent simultaneously.

The Big-O notation simply describes how well an algorithm scales or performs in the worst case scenario as the number of elements in a data structure increases. The Big-O notation can also be used to describe other behavior such as memory consumption. Since the collection classes are actually data structures, we usually use the Big-O notation to chose the best implementation to use, based on time, memory and performance. Big-O notation can give a good indication about performance for large amounts of data.

The finalize method is called by the garbage collector, just before releasing the object’s memory. It is normally advised to release resources held by the object inside the finalize method.

 - When two processes are waiting to update the rows of a table which are locked by another process, the situation is called a deadlock.
 - The reasons for it to happen are:
 * lack of proper row lock commands.
 * Poor design of front-end application
- It reduces the performance of the server severely.
- These locks get automatically released automatically when a commit/rollback operation is performed or any process is killed externally.

ARC is a compiler-level feature that simplifies the process of managing the lifetimes of Objective-C objects. Instead of you having to remember when to retain or release an object, ARC evaluates the lifetime requirements of your objects and automatically inserts the appropriate method calls at compile time.

Open for INPUT, OUTPUT, I-O, EXTEND.

1.INPUT : for read only purpose

2.OUTPUT : for write only purpose

3.EXTEND : for appending records

4.I-O : for read and write(using EXTEND) purpose

Similarity: Both WHERE and HAVING Clause filters out records based on one or more conditions.

Difference: WHERE Clause can only be applied to a static non-aggregated column whereas HAVING is needed for aggregated columns.