Advanced SQL Server Interview Questions and Answers

Introduction

To be effective with database-centric requests (which comprises all the requests Data Warehousing area), one must be sturdy and plentiful in SQL. In this article, we will study further SQL by flouting the topic in the method of numerous question-answer meetings usually asked in Conferences. 

The below-mentioned SQL server interview questions for developers are really useful to crack the job interview.

Basic SQL Server Interview Questions and Answers

Q1). Explain the Meaning of DBMS?

Answer : A Database Management System (DBMS) is a database that assures the formation, upkeeping, and usage of a database. DBMS can be labeled as File Manager that accomplishes data in a database somewhat than convertible it in file arrangements.

Q2). Explain the Meaning of RDBMS?

Answer : RDBMS implies the Relational Database Management System. RDBMS hoard the information into the gathering of tables, which is linked by common fields amid the columns of the table. It also delivers relational operatives to operate the data stowed into the tables. For Instance: SQL Server.

Q3). Explain the meaning of SQL?

Answer : SQL implies the Structured Query Language, and it is cast-off to interconnect with the Database. This is a normal language used to achieve tasks such as recovery, update, supplement, and removal of data from a database. The usual SQL Command is Select.

Q4). Explain the meaning of Database?

Answer :The database is nonentity but a prearranged procedure of data for informal access, storage, recovery, and handling of data. This is also recognized as an organized form of data that can be retrieved in numerous ways. For instance: School Administration Database, Bank Administration Database.

Q5). Explain the Meaning of Tables and Fields?

Answer : A table is a set of information that is prearranged in a framework with Columns and Rows. Columns can be considered upright, and Rows are flat. A table has quantified a number of columns called arenas but can have any quantity of rows which is named as the record.

Q6). Explain the Meaning of Foreign Keys?

Answer : A foreign key is a unique table that can be linked to the main key of an alternative table. Relationships have to be formed between two tables by citing foreign keys with the main key of an alternative table.

Q7). Explain the meaning of a Join?

Answer : This is a keyword cast-off to query data from more counters founded on the relationship amid the fields of the tables. Keys piece the main role when JOINs are cast off.

Q8). What are the Categories of Join and Clarify Each?

Answer : There are numerous types of join that can be cast-off to save data and it depends on the association between tables. Following are the types of join:

• Inner join: Inner join reoccurred rows when there is at least one match of rows amid the tables.
• Right, join Right join reoccurrence rows which are shared amid the tables and all rows of a Right-hand side table. Merely, it proceeds all the rows from the right-hand side table even though there are no bouts in the left-hand side table.
• Left Join: Left join reoccurrence rows which are shared amid the tables and all rows of the Left-hand side table. Merely, it proceeds all the rows from the Left-hand side table even, however, there are no competitions on the Right-hand side table.
• Full Join: Full join reappearance rows when there are corresponding rows in any unique of the tables. This implies, it proceeds all the rows after the left-hand side table and all the rows after the right-hand side table.

Q9). Explain the Term Identity in SQL?

Answer : Answer: An identity column in the SQL inevitably produces numeric standards. We can have well-defined a start and increase the value of the uniqueness column.

Q10). Explain the term Normalization?

Answer : The procedure of table design to mineralize the data idleness is named normalization. We want to divide a database into two or additional tables and describe relationships between them. Normalization is the procedure of mineralizing idleness and dependence by establishing fields and counters of a database. The chief goal of Normalization is to add, delete or adapt fields that can be made in a solitary table.

Q11). What are the different types of major data types in SQL Server? Why there are so many sub-data types like small int, Char, date, small date, etc.

Answer : There are mainly three types of data types in SQL Server

1. Numerical
2. Character
3. Date Time

The sub-data types are meant for memory management. For example, Sex i.e. Male or Female will not require the same memory space as name or address.

Advanced SQL Server Interview Questions and Answers

Q12). Explain the Term Trigger?

Answer : Trigger permits us to implement a batch of SQL code when a table occasion occurs (Insert, appraise or delete command implemented against an exact table).

Q13). When you promote a SQL Server, the elevation wizard seems to stop answering and flops. Why?

Answer : If applications or amenities have exposed ODBC influences to the SQL Server 2005 throughout the adaptation process, they might not permit the SQL Server to be closed totally. The conversion procedure will not continue to the subsequent step if it does not accept confirmation that the SQL Server has been totally still.

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Q14). How to Roll Back the Advancement?

Answer: If the inheritance SQL Server occurrence is replaced by a new-fangled SQL Server 2008 example, rolling back an in-place advancement can be composite and inefficient, whereas in a side-by-side advancement the inheritance instance remains accessible if a rollback is desirable.

Q15). Explain the term De-normalization?

Answer: Denormalization is a method used to contact the information from higher to inferior normal methods of the database. It is also the procedure of presenting severance into a table by including data from the linked tables.

Q16). What are entirely the dissimilar normalizations?

Answer: The usual forms can be alienated into 4 forms, and they are clarified below -.

• First Normal Form (1NF): This must eliminate all the identical columns from the table. Formation of tables for the linked data and documentation of exclusive columns.
• Second Normal Form (2NF): Summit all necessities of the first normal form. Introduction of the subsets of data in distinct tables and Formation of relations amid the tables using main keys.
• Third Normal Form (3NF): This must meet all the necessities of 2NF. Eliminating the columns which are not reliant on main key restraints.
• Fourth Normal Form (4NF): Summit all the necessities of the third normal form and it must not have multi-valued needs.

Q17). Explain the Meaning of View?

Answer : A view is a simulated table that contains a subset of information limited in a table. Views are not practically contemporary, and it receives less space to stock. A view can have information on one or more tables united, and it is contingent on the association.

Q18). Explain the meaning of Index?

Answer : An index is a presentation tuning technique of permitting faster recovery of records from the table. A directory generates an entry for each value and it will be quicker to recover data.

Q19). What Are All the Diverse Types of Indexes?

Answer : There are three kinds of indexes -

• Unique Index: This indexing does not permit the arena to have identical values if the column is exclusively indexed. The exclusive index can be practical mechanically when the main importance is well-defined.
• Clustered Index: This kind of index reorganizes the corporeal order of the table and exploration based on the main values. Separately tables can have only one clustered index.
• Non-Clustered Index: Non-Clustered Index does not modify the corporeal order of the table and preserves logical instruction of information. Every table can have many non-clustered indexes.

Q20). Is It Possible to Add CPU to SQL Server?

Answer : Yes. Addition of CPUs can happen by totaling new-fangled hardware, rationally by online hardware separating, or practically through a virtualization layer. Preliminary with SQL Server 2008, SQL Server provisions hot add CPU.

• Necessitates hardware that provisions hot add CPU.
• Needs the 64-bit version of Windows Server 2008 Datacenter or the Windows Server 2008 Initiative Edition for Itanium-Based Organizations operating a system.
• Necessitates SQL Server Enterprise.
• SQL Server cannot be organized to custom soft NUMA

Once the CPU is supplementary just run RECONFIGURE then SQL server distinguishes the afresh additional CPU.

Q21). How to do advancement in SQL Server 2000 to SQL Server 2008?

Answer : The best method is side-by-side promotion. You can do this either by using the backup and reinstate method or detach/ascribe to the database files. I’d propose using the backup & restore as the harmless method. The steps are:

• Route Advancement Analysis tool from Microsoft. Report any matters raised there, primary.
• Classify DTS packages. These must be wandered by hand, except you buy Pragmatic Works outstanding software. Reconstruct the DTS posts as SSIS.
• Script out entirely SQL Agent jobs.
• Script out all sanctuary
• Holdup the schemes and authenticate the backups (if possible by restoring them to the additional system)
• Run the safety script on the new-fangled system
• Run the reinstate on the new-fangled system.
• Authenticate the databases by consecutively DBCC
• Automatically update all data
• Run the SQL Go-between script

Q22). Can You Separate the SQL Server 2005 Database and Ascribe It to a SQL Server 2008 Server?

Answer : Yes. SQL Server 2005 databases are well-matched with SQL Server 2008. Ascribing a SQL Server 2005 folder to SQL Server 2008 mechanically promotes the SQL Server 2005 database to the last and the folder is then no longer serviceable by the SQL Server 2005 connection.

Q23). What are magic tables? How are they useful in Triggers?

Answer : There are Magic Tables (virtual tables) in SQL Server that hold the temporal information of recently inserted and recently deleted data in the virtual table. INSERTED and DELETED are two types of magic tables in SQL Server. An INSERTED magic table is populated with INSERT and UPDATE operations and DELETED magic table is populated with UPDATE and DELETE operations.

The INSERTED magic table stores the before version of the row, and the DELETED table stores the after version of the row for any INSERT, UPDATE, or DELETE operations.

A magic table can be utilized in INSERT, UPDATE, and DELETE activity with the table in a trigger, which is the common understanding of people. SQL Server uses magic tables outside the TRIGGER also for a lot of other purposes too. Use of Magic tables in SQL Server with the usual update statement lessens the information dependency and makes your information consistent with your transaction.

Q24.)Can you index a table variable? If yes what type of index and why?

Answer : Table variables are declared like standard tables. Only difference is that they are not permanent. The syntax for declaring a table variable is as below.

DECLARE @product_table TABLE (

  ProductID int PRIMARY KEY NOT NULL,

  [Category Name] nvarchar(50) NOT NULL,

  [Subcategory Name] nvarchar(50) NOT NULL,

  [Product Name] nvarchar(50) NOT NULL,

  ListPrice money NOT NULL

);

Since you can define a primary key in a table variable and by default primary key creates a clustered index, so indexing is possible in a table variable and that is clustered index.

Q25) Is trigger applicable only on tables?

Answer :

          Trigger is not applicable only on tables. You can also implement triggers on views and triggers can also be implemented on databases as well. Below is an example.

CREATE TRIGGER LimitConnectionAfterOfficeHours

AS

BEGIN

 IF ORIGINAL_LOGIN() = 'TestUser' AND

  (DATEPART(HOUR, GETDATE())

                  DATEPART (HOUR, GETDATE()) > 18)

 BEGIN

  PRINT 'You are not authorized to login after office hours'

  ROLLBACK

 END

END

This particular trigger checks if a particular login id except Testuser is logged into the system even after a certain time of the day. If yes it logs out the person.

Conclusion

Advanced SQL Server interview questions will help to check your proficiency in the dat  abase. The above content will help you crack your SQL Server interview. You can also register with JanBask Training to enroll for top-level training in technologies.