Asked by: Abderrazzaq Donati
technology and computing databases

What is view in SQL and why it is used?

18
A view is actually a composition of a table inthe form of a predefined SQL query. Views are usedfor security purpose in databases,views restricts the user fromviewing certain column and rows means by using view we canapply the restriction on accessing the particular rows and columnsfor specific user.


Furthermore, what is the purpose of views in SQL?

Use of a View Views are used for security purposesbecause they provide encapsulation of the name of the table. Datais in the virtual table, not stored permanently. Viewsdisplay only selected data. We can also use Sql Join s inthe Select statement in deriving the data for theview.

Additionally, why do we use views instead of tables? Views can provide many advantages overtables: Views can represent a subset of the datacontained in a table. Views can limit the degree ofexposure of the underlying tables to the outer world: agiven user may have permission to query the view, whiledenied access to the rest of the basetable.

what are views How are they useful?

A view is a virtualtable based on the result-set of an SQL Statement. It has rows andcolumns like in a real table but does not hold thedata.

In what situations would you use a view?

Simplicity - Views can be used to hide and reusecomplex queries.

Views can provide advantages over tables:

  • Views can represent a subset of the data contained in atable.
  • Views can join and simplify multiple tables into a singlevirtual table.

Related Question Answers

Chedey Kaloxylos

Professional

Can we insert data into view?

If you are using inner joins, and your viewcontains all the columns in the base tables, then yourview might be updatable. However, for a multiple-tableupdatable view, INSERT can work if it insertsinto a single table. You could split your insertoperation into multiple INSERTstatements.

Jodi Willbers

Professional

What is difference between views and tables?

A view consists of rows and columns just like atable. The difference between a view and atable is that views are definitions built on top ofother tables (or views), and do not hold datathemselves. Space savings: Views takes very little space tostore, since they do not store actual data.

Yered Norman

Professional

What view means?

A view is a subset of a database that isgenerated from a query and stored as a permanent object. Althoughthe definition of a view is permanent, the datacontained therein is dynamic depending on the point in time atwhich the view is accessed. Views represent a subsetof the data contained in a table.

Pilar Nowicki

Explainer

What is view explain with example?

Views in SQL are kind of virtual tables. Aview also has rows and columns as they are in a real tablein the database. We can create a view by selecting fieldsfrom one or more tables present in the database. A View caneither have all the rows of a table or specific rows based oncertain condition.

Huilin Cousin

Explainer

Can we update view in SQL?

If the view contains joins between multipletables, you can only insert and update one table inthe view, and you can't delete rows. You can'tdirectly modify data in views based on union queries. Youcan't modify data in views that use GROUP BY orDISTINCT statements.

Lioudmila Julian

Explainer

What are the advantages of views in SQL?

The following are advantages of using databaseviews.
  • A database view allows you to simplify complex queries: adatabase view is defined by an SQL statement that associates withmany underlying tables.
  • A database view helps limit data access to specific users.
  • A database view provides extra security layer.

Maricielo Senajit

Pundit

What is the use of a view in SQL?

Views are nothing but logical tables or you cansay it as virtual table whch is used to fetch the recordsfrom one or more tables.Basically views are used forreporting purpose in sql.Views are used torestrict a data.Means if Employee table contains 3 fieldseno,ename,salary but we want to show only eno,ename toend

Reduan Escrig

Pundit

Why we use triggers in SQL?

A database trigger is special stored procedurethat is run when specific actions occur within a database. Mosttriggers are defined to run when changes are made to atable's data. Triggers can be defined to run instead of orafter DML (Data Manipulation Language) actions such as INSERT,UPDATE, and DELETE.

Abderrafia Ahaddouch

Pundit

What is a view in DBMS?

A database view is a searchable object in adatabase that is defined by a query. Though a view doesn'tstore data, some refer to a views as “virtual tables,”you can query a view like you can a table. A view cancombine data from two or more table, using joins, and also justcontain a subset of information.

Don Schiesswohl

Pundit

What is the use of NVL function?

The NVL( ) function is available inOracle, and not in MySQL or SQL Server. This function isused to replace NULL value with another value. It is similarto the IFNULL Function in MySQL and the ISNULLFunction in SQL Server.

Nosakhare Ruess

Pundit

What is the role of view in DBMS?

A view contains rows and columns, just like areal table. The fields in a view are fields from one or morereal tables in the database. You can add SQL functions,WHERE, and JOIN statements to a view and present the data asif the data were coming from one single table.

Tomita Fedchenko

Teacher

What is the trigger?

In a DBMS, a trigger is a SQL procedure thatinitiates an action (i.e., fires an action) when an event (INSERT,DELETE or UPDATE) occurs. Since triggers are event-drivenspecialized procedures, they are stored in and managed by theDBMS.

Angely Pedrouso

Teacher

Does View store data in Oracle?

Unlike a table, a view does not store anydata. To be precise, a view only behaves like atable. And it is just a named query stored in thedatabase.

Ehari Cejuela

Teacher

What is primary key in database?

A primary key is a special relationaldatabase table column (or combination of columns) designatedto uniquely identify all table records. A primary key's mainfeatures are: It must contain a unique value for each row of data.It cannot contain null values.

Sharie Vorner

Teacher

What is database join?

A join is an SQL operation performed to establisha connection between two or more database tables based onmatching columns, thereby creating a relationship between thetables. Most complex queries in an SQL database managementsystem involve join commands.

Code Basto

Reviewer

What describes a query?

A query is a question, often expressed in aformal way. A database query can be either a selectquery or an action query. A select query is adata retrieval query, while an action query asks foradditional operations on the data, such as insertion, updating ordeletion.

Gillermo Grazina

Reviewer

What are views in mysql?

MySQL supports views, including updatableviews. Views are stored queries that when invokedproduce a result set. A view acts as a virtual table.

Rosali Damasio

Reviewer

Are views faster than tables?

It all depends on the situation. MS SQL Indexedviews are faster than a normal view or query butindexed views can not be used in a mirrored databaseinvironment (MS SQL). Same as a query. In this situation atemporary table using # or @ to hold your data to loopthrough is faster than a view or a query.

Mohand Given

Reviewer

Can we create view on view?

A view can contain all rows of a table or selectrows from a table. A view can be created fromone or many tables which depends on the written SQL query tocreate a view.

Co-Authored By:

EveryThingWhat Staff Editor

3

7th March, 2020

45

80% of readers found this page helpful.

4/5

Click a star to add your vote

Similar Asks
Trending