SQL server views interview questions and answers

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Define Views.
What is Indexed view? How to create it?
What are partitioned views and distributed partitioned views?
What functions can a view be used to performed?
Describe the functionalities that views support.
Explain Indexed views and partitioned view with their syntax.
What are the restrictions that views have to follow?

SQL Server views - August 29, 2008 at 18:00 PM by Nishant Kumar Define Views. View can be created to retrieve data from one or more tables. Query used to create view can include other views of the database. We can also access remote data using distributed query in a view. Views - October 24, 2008 at 18:10 pm by Rajmeet Ghai What is Indexed view? How to create it? In an indexed view, the data is already computed and stored. Data can be accessed by a unique index. This index is a clustered index. In order to create an index the syntax is CREATE [UNIQUE], [CLUSTERED | NONCLUSTERED] INDEX index_name ON {view} [WITH <index_option>] [ON filegrp] What are partitioned views and distributed partitioned views? Partitioned views allow data in a large table to be split into smaller tables. These small tables are called as member tables. The split is done based on range of data values in one of the columns. In a distributed portioned view, each member table is on a separate member server. This means that the member tables are distributed. To locate these tables easily, the database name on each server should be same. What functions can a view be used to performed? Functions of View:- Subset data of a table Can join multiple tables values into one They can act as aggregated tables. i.e. a view can be used to store Sum, average of values Views can be nested and can be used for abstraction Define views. Answer A view can be considered as a virtual table. It does not physically exist. It is based on the result set of a SQL statement. A view contains rows and tables just like a real table. Describe the functionalities that views support. Answer Views can subset data in a table They can join multiple tables into one virtual table Views can provide security and decrease complexity They save space because only their definition is stored. They can also be used to create abstraction Materialized views are commonly used in data warehousing. They represent a snapshot of the data from remote sources. Views can create other calculated fields based on values in the real underlying tables Explain Indexed views and partitioned view with their syntax. Answer Indexed view: An index view has a unique clustered index created on it. They exist as rows on the disk. Because they are saved on the disk, the response time to a query is fast at the cost of space consumption. They are more commonly used in scenarios when data modification is less. Syntax: Create Index CREATE [UNIQUE ] [ CLUSTERED | NONCLUSTERED ] INDEX index_name ON table_name The view is created using the CREATE VIEW synatx Partitioned view: Partitioned view joins the horizontally portioned data. This data may belong to one ore more servers. It makes the data appear as one table. A portioned view can either be local or distributed. A local portioned view resides on the same instance of the SQL server while the distributed may reside on a different server. Syntax: The view is then created by UNIONing all the tables and an updateable partitioned View results Server 1 : CREATE TABLE Customer1 (CustomerID INTEGER PRIMARY KEY CHECK (CustomerID BETWEEN 1 AND 32999), ... -- Additional column definitions) Similar tables created for Server 2 and 3 Partitioned view for server 1 CREATE VIEW Customers AS SELECT * FROM CompanyDatabase.TableOwner.Customer1 UNION ALL SELECT * FROM Server2.CompanyDatabase.TableOwner.Customer2 UNION ALL SELECT * FROM Server3.CompanyDatabase.TableOwner.Customer3 What are the restrictions that views have to follow? Answer Since a view is a virtual table – columns of the view cannot be renamed. To change anything in the view, the view must be dropped and create again. The select statement on the view cannot contain ORDER BY or INTO TEMP When a table or view is dropped, any views in the same database are also dropped. It is not possible to create an index on a view It is not possible to use DELETE to update a view that is defined as a join. <<Previous  Next>> Also read What are the rules to use the ROWGUIDCOL property to define a globally unique identifier column? Answer - A table can have only one ROWGUIDCOL column...... Describe in brief system database. Answer - Master database is system database. It contains information about server’s configuration. It is a very important database and important to backup Master..... Describe in brief SQL Server monitoring ways. Answer - SQL Profiler is a tool that stores events from the server. SQL Profiler saves the events in the trace file...... SQL Server Optimization Tips Answer - Restricting query result means return of required rows instead of all rows of the table. This helps in reducing network traffic...... Describe in brief authentication modes in SQL server. Answer - This is the default and recommended security mode. 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