Index In SQL Server Part VI

Index In SQL Server

Index :

  • Indexes are used to improve the performance of  searching, Because they are in sequential format it helps the searching operation.
  • An index is an on-disk structure associated with a table or view that speeds retrieval of rows from the table or view.
  • An index contains keys built from one or more columns in the table or view.
  • These keys are stored in a structure (B-tree) that enables SQL Server to find the row or rows associated with the key values quickly and efficiently.
A table or view can contain the following two types of indexes :


1) Clustered Index :
  • Clustered Index arranges the indexes in the form of the Balanced Tree Structure(B-Tree).
  • In SQL server clustered index is created automatically, when a primary key is created.
  • There can be only one clustered index per table, because the data rows themselves can be stored in only one order.  
Creating Clustered Index in SQL Server : 

1) Go to Design of a table, then Right click on column and select Indexes/Keys :

2) The Table Designer set Create As Clustered as Yes,then Clustered Index is created Successfully :

2) Non-Clustered Index :

  • In Non-Clustered Index, it also arranges a Balanced tree structure.
  • There can be multiple non-clustered index per table, because the data rows themselves can be stored in multiple order.  
Creating Non-Clustered Index in SQL Server : 

1) Go to Design of a table, then Right click on column select and open Indexes/Keys then click Add & Select the column name :

2) Select type to index :

SQL Plan :

  • The SQL plan is nothing but is the plan by SQL server created while executing.
  • Then the query is written completely.
  • You can directly click the “Display Estimated Execution Plan” toolbar button :

Example :


Comments

Post a Comment

Popular posts from this blog

Basic Concept In C Sharp Day 16

Image
Lecture 16 : Basic Concept In C Sharp C Sharp : C#  (pronounced  see sharp , like the musical note C♯, but written with the number sign) is a general-purpose, multi-paradigm programming language encompassing static typing, strong typing, lexically scoped, imperative, declarative, functional, generic, object-oriented (class-based), and component-oriented programming disciplines. C# was developed around 2000 by Microsoft as part of its .NET initiative and later approved as an international standard by Ecma (ECMA-334) in 2002 and ISO (ISO/IEC 23270) in 2003. It was designed by Anders Hejlsberg, and its development team is currently led by Mads Torgersen, being one of the programming languages designed for the Common Language Infrastructure (CLI). The most recent version is 9.0, which was released in 2020 in .NET 5.0 and included in Visual Studio 2019 version 16.8. C-sharp musical note : " C sharp " was inspired by the musical notation whereby a sharp symb
Read more

Understanding C Sharp Day 18

Image
Lecture 18 : Understanding C Sharp   Class Library : A class library  defines types and methods that are called by an application. The  Class Library .DLL  contains program code, data, and resources that can be can used by other programs and are easily implemented into other Visual Studio projects. Create New Class Library Project with Visual Studio :  Create New Project : Select C# in the language tab And then select  Class Library (.NET Framework) and press the NEXT button You can then proceed to give your project a Project Name Call the project  MathLibrary  (in order to copy/paste example code) Press the CREATE button, After you have given a name to your project Building the Class Library .DDL for C# : The following code example is a C# version of the Class Library.  The Class Library .DLL contains program code, data, and resources.  The Class Library in this example will feature a custom Math API that has a set of functions to Substract, Devide and Multiply numbers.
Read more

Concept In Angular Day 14

Image
Lecture 14 : Concept In Angular What is ngModel : ngModel is Angular’s answer to the two-way data binding problem. Previously in AngularJS, there was no way to perform a binding which would update automatically. What are Directives : Directives are markers on a DOM element that tell AngularJS to attach a specified behaviour to that DOM element or even transform the DOM element and its children. Angular includes various built-in directives. In addition to this, you can create custom directives for your application. ng-model Directive : The ng-model directive binds the value of HTML controls (input, select, textarea) to application data. With the ng-model directive you can bind the value of an input field to a variable created in AngularJS. Two-Way Binding : The binding goes both ways. If the user changes the value inside the input field. Two-way binding, we can display a data property as well as an update that property when the user makes changes. Two-way binding
Read more