Question 1

Which dml command is used in conjunction with @@identity?

Accepted Answer

Using automatically incrementing IDENTITY columns is very popular with database developers. You don’t need to explicitly calculate unique surrogate keys when inserting new data, the IDENTITY column functionality does that for you. The IDENTITY feature also allows you to specify useful Seed and Increment properties. When you use an INSERT statement to insert data into a table with an IDENTITY column defined, SQL Server will generate a new IDENTITY value. You can use the @@IDENTITY variable and the SCOPE_IDENTITY and IDENT_CURRENT functions to return the last IDENTITY value that has been generated by SQL Server. This is very useful when you need to return the key for the row that has just been inserted, back to the caller.

Question 2

What is the maximum number of triggers, can apply to a single table?

Accepted Answer

Maximim number of triggers that can be applied to a single table is 12

Question 3

What is the output after compile and run the following code ? int Output = 10; boolean b = false; if((b == true) && ((Output += 10) == 20)) { System.out.println("We are equal " + Output); } else { System.out.println("Not equal! " + Output); }

Accepted Answer

The output will be "Not equal! 10". Please note that && is logical AND operator. If first operand before (&&) is false then the other operand will not be evaluated. This illustrates that the Output +=10 calculation was never performed because processing stopped after the first operand was evaluated to be false. If you change the value of b1 to true, processing occurs as you would expect and the output would be "We are equal 20".

Question 4

In the following pieces of code, B and D will compile without any error. True or false ? A: StringBuffer sb1 = "abcd"; B: Boolean b = new Boolean("abcd"); C: byte b = 255; D: int x = 0x1234; E: float fl = 1.2;

Accepted Answer

The code segments B and D will compile without any error. A is not a valid way to construct a StringBuffer, you need to create a StringBuffer object using "new". B is a valid construction of a Boolean (any string other than "true" or "false" to the Boolean constructor will result in a Boolean with a value of "false"). C will fail to compile because the valid range for a byte is -128 to +127 (i.e., 8 bits, signed). D is correct, 0x1234 is the hexadecimal representation in java. E fails to compile because the compiler interprets 1.2 as a double being assigned to a float (down-casting), which is not valid. You either need an explicit cast, as in "(float)1.2" or "1.2f", to indicate a float.

Question 5

In R-DBMS, the data is organized in the form of _____.

Accepted Answer

Data is organized in the form of row and columns, thus it is in tabular structure.

Question 6

How many joining conditions are required to join 4 tables in SQL?

Accepted Answer

To join 'n' tables 'n-1' conditions should be satisfied. So to join 4 tables 3 conditions should be satisfied.

Question 7

What is the default return value of a function?

Accepted Answer

The default return value from a function is int. In other words, unless explicitly specified the default return value by compiler would be integer value from function.

Question 8

MOV extension refers usually to what kind of files?

Accepted Answer

A .MOV file is a common multimedia container file format developed by Apple. It may contain multiple tracks that store different types of media data and is often used for saving movies and other video files.

Question 9

Which among the following keys are used to identify each row of the table uniquely?

Accepted Answer

Primary key helps us to identify a row uniquely in a relation

Oracle Certification Questions