Interview Questions

A collection just like an array is an ordered group of elements of the same type. Each elements position is determined by a unique subscript.

Index by tables:- They are similar to hash arrays that allows to search for subscript values using arbitrary numbers and strings.

They can be declared as:

TYPE type_name IS TABLE OF element_type [NOT NULL]

INDEX BY [BINARY_INTEGER | PLS_INTEGER | VARCHAR2(size_limit)];

INDEX BY key_type;

Example:

TYPE studenttyp IS TABLE OF emp%ROWTYPE

INDEX BY BINARY_INTEGER;

stud_tab studenttyp;

Nested tables:- they hold random number of elements and use sequential numbers as sub scripts.

They can be declared as:

TYPE type_name IS TABLE OF element_type [NOT NULL];

Example: TYPE employee_type IS TABLE OF NUMBER INDEX BY VARCHAR2(64);

Varrays: Holds a fixed number of elements which can be changed in run time. 

They can be declared as:

TYPE type_name IS {VARRAY | VARYING ARRAY} (size_limit) OF element_type [NOT NULL];

Example: TYPE Calendar IS VARRAY(366) OF DATE;

Time Estimation method for Testing Process:

Step 1 : count number of use cases (NUC) of system 

Step 2 : Set Avg. Time Test Cases(ATTC) as per test plan 

Step 3 : Estimate total number of test cases (NTC) 

Total number of test cases = Number of Use Cases X Avg. Test Cases per a use case 

Step 4 : Set Avg. Execution Time (AET) per a test case 

Step 5 : Calculate Total Execution Time (TET) 

TET = Total number of test cases * AET 

Step 6 : Calculate Test Case Creation Time (TCCT)

usually we will take 1.5 times of TET as TCCT

TCCT = 1.5 * TET

Step 7 : Time for Re-Test Case Execution (RTCE) this is for retesting

usually we take 0.5 times of TET

RTCE = 0.5 * TET

Step 8 : Set Report generation Time (RGT

usually we take 0.2 times of TET

RGT = 0.2 * TET

Step 9 : Set Test Environment Setup Time (TEST)

it also depends on test plan

Step 10 : Total Estimation time = TET + TCCT+ RTCE + RGT + TEST + some buffer.

A stored procedure is a segment of declarative SQL statements stored inside the database catalog. A stored procedure can be invoked by triggers, other stored procedures or applications such as Java, C#, PHP, etc.

Advantages 

- Typically stored procedures help increase the performance of the applications. Once created, stored procedures are compiled and stored in the database. However MySQL implements the stored procedures slightly different. MySQL stored procedures are compiled on demand. After compiling a stored procedure, MySQL puts it to a cache. And MySQL maintains its own stored procedure cache for every single connection. If an application uses a stored procedure multiple times in a single connection, the compiled version is used, otherwise the stored procedure works like a query.

- Stored procedures helps reduce the traffic between application and database server because instead of sending multiple lengthy SQL statements, the application has to send only name and parameters of the stored procedure.

- Stored procedures are reusable and transparent to any applications. Stored procedures expose the database interface to all applications so that developers don’t have to develop functions that are already supported in stored procedures.

- Stored procedures are secure. Database administrator can grant appropriate permissions to applications that access stored procedures in the database without giving any permission on the underlying database tables.

Disadvantages

- If you use a lot of stored procedures, the memory usage of every connection that is using those stored procedures will increase substantially. In addition, if you overuse a large number of logical operations inside store procedures, the CPU usage will also increase because database server is not well-designed for logical operations.

- A constructs of stored procedures make it more difficult to develop stored procedures that have complicated business logic.

- It is difficult to debug stored procedures. Only few database management systems allow you to debug stored procedures. Unfortunately, MySQL does not provide facilities for debugging stored procedures.

-It is not easy to develop and maintain stored procedures. Developing and maintaining stored procedures are often required specialized skill set that not all application developers possess. This may lead to problems in both application development and maintenance phases.

- The better way to design the layout of the webpage is by using the <div> tag. 

- The <table> tag is used to present the data in tabular format

As a manager, the tough decisions I make involve layoffs. Before making those hard decisions, I always think particularly about what is best for my employees and the business. While I do not relish making those kinds of decisions, I do not shy away from this part of my job. Two years ago, I had to let some employees go due to the monetary climate. This was a tough decision that was ultimately necessary for the good of the organization and everyone working for the company.

We need to first login to the data base as: SQLPLUS followed by user_name/password. Then we need to execute the following query:

CREATE USER user_name IDENTIFIED BY abcd; in this query a user_name suggest the user that is created which has a password abcd which is required for login in database.

Recovery/error testing is testing how well a system recovers from crashes, hardware failures, or other catastrophic problems.

"==" checks equality only,
"===" checks for equality as well as the type.