Technology Questions

 - 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.

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.

A static method cannot access non static variables or methods because static methods doesnt need the object to be accessed. So if a static method has non static variables or non static methods which has instantiated variables they will no be intialized since the object is not created and this could result in an error.

WATER MARK is a divided segment of used and free blocks. Blocks which are below high WATER MARK i.e. used blocks, have at least once contained some data. This data might have been deleted later. Oracle knows that blocks beyond high WATER MARK don’t have data; it only reads blocks up to the high WATER MARK during a full table scan. 

In C++, void represents the absence of type, so void pointers are pointers that point to a value that has no type. The void pointers can point to any data type.

You can declare void pointer as follows:

void *p;

A DB2 bind is a process that builds an access path to DB2 tables. 

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.