- Are views faster than queries?
- What are the after triggers?
- What is view in DBMS Mcq?
- Which is faster view or table?
- Can we insert row in view?
- What Cannot be done on a view?
- Can we insert data in view oracle?
- What is a view vs a table?
- Why do we create view in SQL?
- How can we insert data into a view Mcq?
- Why can’t I use outer join in an indexed view?
- How do I make SQL run faster?
- Are views stored in database?
- Can you add index to a view?
- What can be done on a view?
- How do you display in SQL?
- Can we insert and delete rows into a view?
- What is the advantage of view in SQL?
Are views faster than queries?
Views make queries faster to write, but they don’t improve the underlying query performance.
In short, if an indexed view can satisfy a query, then under certain circumstances, this can drastically reduce the amount of work that SQL Server needs to do to return the required data, and so improve query performance..
What are the after triggers?
After Trigger, Instead of Trigger ExampleAfter Trigger (using FOR/AFTER CLAUSE) This trigger fires after SQL Server completes the execution of the action successfully that fired it. … Instead of Trigger (using INSTEAD OF CLAUSE) This trigger fires before SQL Server starts the execution of the action that fired it.
What is view in DBMS Mcq?
This set of SQL Server Multiple Choice Questions & Answers (MCQs) focuses on “Views”. … Explanation: VIEW is a virtual table, through which a selective portion of the data from one or more tables can be seen. A view do not contain data of their own. 2.
Which is faster view or table?
MS SQL Indexed views are faster than a normal view or query but indexed views can not be used in a mirrored database invironment (MS SQL). … Same as a query. In this situation a temporary table using # or @ to hold your data to loop through is faster than a view or a query. So it all depends on the situation.
Can we insert row in view?
You can insert rows into a view only if the view is modifiable and contains no derived columns. … When a modifiable view contains no derived columns, you can insert into it as if it were a table. The database server, however, uses NULL as the value for any column that is not exposed by the view.
What Cannot be done on a view?
What cannot be done on a view? Explanation: In MySQL, ‘Views’ act as virtual tables. It is not possible to create indexes on a view. However, they can be used for the views that are processed using the merge algorithm.
Can we insert data in view oracle?
4 Answers. Views in Oracle may be updateable under specific conditions. … An updatable view is one you can use to insert, update, or delete base table rows. You can create a view to be inherently updatable, or you can create an INSTEAD OF trigger on any view to make it updatable.
What is a view vs a table?
A view is a virtual table. A view consists of rows and columns just like a table. The difference between a view and a table is that views are definitions built on top of other tables (or views), and do not hold data themselves. If data is changing in the underlying table, the same change is reflected in the view.
Why do we create view in SQL?
Views are used for security purposes because they provide encapsulation of the name of the table. Data is in the virtual table, not stored permanently. Views display only selected data. We can also use Sql Join s in the Select statement in deriving the data for the view.
How can we insert data into a view Mcq?
How can we insert data into a view? Explanation: We can insert data into a view using the inset into values ( ); statement. This operation can be done only if the view is updatable. Explanation: We can update a view only if it has a single database relation in the “from” clause.
Why can’t I use outer join in an indexed view?
Q: Why can’t I use OUTER JOIN in an Indexed view? A: Rows can logically disappear from an Indexed view based on OUTER JOIN when you insert data into a base table. … In addition, the performance of the implementation would be slower than for views based on standard (INNER) JOIN.
How do I make SQL run faster?
10 More Do’s and Don’ts for Faster SQL QueriesDo use temp tables to improve cursor performance. … Don’t nest views. … Do use table-valued functions. … Do use partitioning to avoid large data moves. … If you must use ORMs, use stored procedures. … Don’t do large ops on many tables in the same batch. … Don’t use triggers. … Don’t cluster on GUID.More items…•
Are views stored in database?
A view is a virtual table whose contents are defined by a query. Like a table, a view consists of a set of named columns and rows of data. Unless indexed, a view does not exist as a stored set of data values in a database.
Can you add index to a view?
Microsoft SQL Server allows you to add an index to a view, but why would you want to do this? To speed up the queries. Not always. By creating a clustered index on a view, you materialize the view, and updates to the underlying tables physically update the view.
What can be done on a view?
A view can hide the complexity that exists in a multiple table join. Views allows the user to select information from multiple tables without requiring the users to actually know how to perform a join. Views can be used to store complex queries.
How do you display in SQL?
The SQL SELECT StatementSELECT column1, column2, … FROM table_name;SELECT * FROM table_name;Example. SELECT CustomerName, City FROM Customers;Example. SELECT * FROM Customers;
Can we insert and delete rows into a view?
You can insert, update, and delete rows in a view, subject to the following limitations: If the view contains joins between multiple tables, you can only insert and update one table in the view, and you can’t delete rows. You can’t directly modify data in views based on union queries.
What is the advantage of view in SQL?
Views can provide advantages over tables: Views can represent a subset of the data contained in a table. Consequently, a view can limit the degree of exposure of the underlying tables to the outer world: a given user may have permission to query the view, while denied access to the rest of the base table.