Interview Questions

Constraints enable the RDBMS to enforce the integrity of the database automatically, without the need to create triggers, rule or defaults.

Types of Constraints: NOT NULL, CHEQUE, UNIQUE, PRIMARY KEY, FOREIGN KEY.

Layer objects are data objects which represent visual content. Layer objects are used by views to render their content. Custom layer objects can also be added to the interface to implement complex animations and other types of sophisticated visual effects.

Primary key constraint ensures that the column(s) always has a unique value to identify the record.
Example:
Below, the primary key is created for column id with name prim_id.
create table employee ( id number NOT NULL, Name varchar(200) Constraint prim_id primary key(id) );

the layer that establishes ,manages and terminates the session between two communticating devices

The following are the areas of concern for tuning:

- Memory Usage

- Data Storage

- Data Manipulation

- Physical Storage

- Logic Storage

- Network Traffic

Tuning Memory Usage: In Oracle 10g, we can use the Automatic Workload Repository (AWR) toolset to gather and manage statistical data but in case of Oracle 11g, we can use new initialization parameters such as MEMORY_TARGET to further control the overall memory used by Oracle. It helps us to tune the database automatically when we don’t have time to read the AWR report.

Tuning Data Manipulation: There are two ways to tune Data manipulation in Oracle one way is through Conventional Path mode and second is Direct Path mode.

Tuning Physical Storage: We need to tune the physical storage because it limits the disk in database. This can be done by: Distributing I/O, Striping and Mirroring.

Whenever there is local- variable/parameter inside the method with same name as data member.

Ex:

Class Sample {

 int a;

  void show() {

   int a=5;

   system.out.println(a); // 5

   system.out.println(this.a);//23

  }

}

class MainApp {

  Public static void main(String[] args) {

  Sample s = new Sample();

   s.a = 23;

   s.show();

   }

}

The QA testing process that was followed in my last company where I worked was like this: First of all the Business Requirement Document was prepared as per the client’s requirement (with the muck-up screen shots). Then on the basis of the requirement document, Test Strategy, Test Plans and Test Cases were written in sequential order. Once the Build is made and deployed to the different testing environments where different types of testing were performed to check whether there are any defects.