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- Question
Difference between Candidate key and Primary key?
- Correct Answer
- Candidate Key ? A Candidate Key can be any column or a combination of columns that can qualify as unique key in database There can be multiple Candidate Keys in one table Each Candidate Key can qualify as Primary Key Primary Key ? A Primary Key is a column or a combination of columns that uniquely identify a record Only one Candidate Key can be Primary Key One needs to be very careful in selecting the Primary Key as an incorrect selection can adversely impact the database architect and future normalization For a Candidate Key to qualify as a Primary Key, it should be Non-NULL and unique in any domain
- 1. What is the maximum number of triggers, can apply to a single table?
Options- A. 8
- B. 10
- C. 12
- D. 14 Discuss
- 2. Which dml command is used in conjunction with @@identity?
Options- A. INSERT and UPDATE
- B. UPDATE and DELETE
- C. SCOPE_IDENTITY and IDENT_CURRENT
- D. Commit and rollback Discuss
- 3. What is Primary Key in DBMS? Discuss
- 4. You are choosing a Windows 2000 operating system to use on a new computer at your company. This new computer will be a heavily used SQL server in your enterprise network environment. which operating system should you choose?
Options- A. Windows 2000 professional
- B. Windows 2000 Server
- C. Windows 2000 Advanced Server
- D. Windows 2000 Datacenter Server Discuss
- 5. You use two sites on your Windows 2000 network. You decide you want to manually specify a particular domain controller in each site that will be used for intersite replication. What should you do?
Options- A. Create a site link to connect the two domain controllers
- B. Designate the desired domain controller in each site as a bridge-head server
- C. Configure the desired domain controller in each site to be a global catalog server
- D. Create a new connection object for the desired domain controller in each site Discuss
- 6. Why do you need common fields in a Database? Discuss
- 7. 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); }
Options- A. Compilation and output of "We are equal 10"
- B. Compilation and output of "Not equal! 10"
- C. Compilation error, attempting to perform binary comparison on logical data type
- D. Compilation and output of "Not equal! 20" Discuss
- 8. 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;
Options- A. TRUE
- B. FALSE Discuss
- 9. Define Executive Plan in Database SQL ? Discuss
- 10. Insert command falls in which sub-language of SQL ?
Options- A. DCL
- B. DQL
- C. DML
- D. DDL Discuss
Oracle Certification problems
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Correct Answer: 12
Explanation:
Maximim number of triggers that can be applied to a single table is 12
Correct Answer: SCOPE_IDENTITY and IDENT_CURRENT
Explanation:
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.
Correct Answer: A primary key is a special relational database table column or combination of columns designated to uniquely identify all table records That is, A primary key is a column or set of columns in a table that uniquely identifies tuples (rows) in that table A primary key, also called a Primary Keyword Main Features Primary key are :: It must contain a unique value for each row of data It cannot contain null values
Correct Answer: Windows 2000 Advanced Server
Explanation:
Windows 2000 Advanced Server is optimized for use on servers (such as SQL servers) in an enterprise network environment.
Correct Answer: Designate the desired domain controller in each site as a bridge-head server
Explanation:
The server that is designated as the bridgehead server is used for intersite replication.
Correct Answer: A database that contains multiple tables related through common fields A common field is a field of data that is shared among all forms in a database Without them, it would be difficult and/or time-consuming to create other forms
Correct Answer: Compilation and output of "Not equal! 10"
Explanation:
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".
Correct Answer: TRUE
Explanation:
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.
Correct Answer: Executive plan can be defined as: * SQL Server caches collected procedure or the plan of query execution and used thereafter by subsequent calls * An important feature in relation to performance enhancement * Data execution plan can be viewed textually or graphically
Correct Answer: DML
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