How to Create and Manage Indexes in SQL Server

Database developer is often required to improve the performance of queries. SQL Server allows implementing indexes to reduce the execution time of queries. In addition they can restrict the view of data to different users by implementing views.

The SQL Server also provides an in-built full-text search capability that allows fast searching of data. This article discusses how to create and manage indexes and views.

Creating and Managing Indexes

When a user queries data from a table based on conditions, the server scans all the data stored in the database table. With an increasing volume of data, the execution time for queries also increases. As a database developer, you need to ensure that the users are able to access data in the least possible time. SQL Server allows you to create indexes on tables to enable quick access to data. In addition, SQL Server allows you to create XML indexes for columns that store XML data.

At times, the table that you need to search contains voluminous data. In such cases, it is advisable to create partitioned indexes. A partitioned index makes the index more manageable and scale able as they store only data of a particular partition.

As a database developer, you need to create and manage indexes. Before creating an index, it is important to identify the different types of indexes.

Identifying the Types of Indexes

Before identifying the types of indexes, it is important to understand the need to implement an index.
The data in the database tables is stored in the form of data pages. Each data page is 8 KB in size. Therefore, data of the complete table is stored in multiple data pages. When a user queries a data value from the table, the query processor searches for the data value in all the data pages. When it finds the value, it returns the result set. With an increasing volume of data, this process of querying data takes time.

To reduce the data query time, the SQL Server allows you to important indexes on tables. An index is a data structure associated with a table that helps in fast search of data in the table. Indexes in the SQL Server are like the indexes at the back of a book that you can use to locate text in the book.

Benefits provided by using Indexes:

• Accelerate queries that join tables, and perform sorting and grouping
• Enforce uniqueness of rows, (if configured for that)

An index contains a collection of keys and pointers. Keys are values built from one or more columns in the table with which the key is associated. The column on which the key is built is the one on which the data is frequently searched. Pointers store the address of the storage location where a data page is stored in the memory, as depicted in the following figure.

When the users query data with conditions based on the key columns, the query processor scans the indexes, retrieves the address of the data page where the required data is stored in the memory, and accesses the information. The query processor does not need to search for data in all the data pages. Therefore, the query execution time is reduced.

The keys in the indexes are stored in a B-Tree in the memory. A B-Tree is a data-indexing method that organizes the index into a multi-level set of nodes. Each page in an index B-Tree is called an index node. Each index contains a single root page at the top of the tree. This root page, or root node, branches out into n number of pages at each intermediate level until it reaches the bottom, or leaf level, of the index. The index tree is traversed by following pointers from the upper-level pages down through the lower-level pages.

The key values in the root page and the intermediate pages are sorted in the ascending order. Therefore, in the B-Tree structure, the set of nodes on which the server will search for data values is reduced. This enables the SQL Server to find the records associated with the key values quickly and efficiently. When you modify the data of an indexed column, the associated indexes are updated automatically.

Complaints Management Project in ASP.NET

Download this project

Project cost : 200Rs or $8
Pay me at:
PayPal id : saini1987tarun@gmail.com

Via bank transfer

ICICI bank account number is :    153801503056
Account holder name is :                 Tarun kumar saini
IFSC code is :                                   ICIC0001538

SBBJ bank detail :                             61134658849
Account holder name:                        Tarun kumar saini
IFSC code :                                        SBBJ0010398

CONTACT ME

narenkumar851@gmail.com

Introduction

In this project, you can create your complaints to admin department. Review your complaints by the admin department and try to solve the problem.

Project Module

I have two module in this project first one is consumer module and last one admin module.

How to work(Step by step guide)

Step-1 : First to complete the consumer registration.
Step-2 :  Login in your account using consumer login panel.
Step-3 : Fill the complaints form, after login.
Step-4 : Check Status after few time in consumer panel.
Step-5 : Open Admin account using admin login panel.
Step-6 : Check New or old consumer complaints and try to solve the problem if possible.
Step-7 : Update the pending status

Requirements

Software : Visual Studio 2010

Project Screen

Home page

Code 

<%@ Page Title="Home Page" Language="C#" MasterPageFile="~/Site.master" AutoEventWireup="true"

    CodeFile="Default.aspx.cs" Inherits="_Default" %>

<%@ Register src="UserControl/complaintform.ascx" tagname="complaintform" tagprefix="uc1" %>

<asp:Content ID="HeaderContent" runat="server" ContentPlaceHolderID="HeadContent">

</asp:Content>

<asp:Content ID="BodyContent" runat="server" ContentPlaceHolderID="MainContent">

    <h2>

        Complaint Form Fill by Consumer</h2>

    <p>

        <table style="width:100%;">

            <tr>

                <td>

                    <uc1:complaintform ID="complaintform1" runat="server" />

                </td>

                <td valign="top">

                    <asp:Image ID="Image1" runat="server" Height="526px" 

                        ImageUrl="~/images/complaint-handling-cartoon.jpg/" Width="340px" />

                </td>

            </tr>

        </table>

    </p>

<p>

        &nbsp;</p>

    </asp:Content>

Consumer login Form

Solution Explorer View

How to download this project

Step-1 : mail to me  ( narenkumar851@gmail.com)
Step-2 : Project Cost $10  or 400 Rs

How to Modify XML Data using Functions in SQL Server

Similar to any other type of data, programmer might also need to modify the XML data. To modify data, you can use the modify function provided by the XML data type of the SQL Server. The modify function specifies an XQuery expression and a statement that specifies the kind of modification that needs to be done.

This function allows you to perform the following modifications:

• Insert: Used to add nodes to XML in an XML column or variable. For example, the management of AdventureWorks wants to add another column specifying the type of customer, in the CustDetails table. The default value in the Type column should be ‘Credit’. To resolve this problem, the database developer of AdventureWorks will create the following query:
  
  UPDATE CusomtDetails SET Cust_Details.modify (‘ inser attribute Type{“Credit”} as first into (/Customer) [1]’)
  
• Replace: Used to update the XML data. For example, James Stephen, one of the customers of AdventureWorks, has decided to change his customer type from Credit to Cash. As a database developer, you can create the following query to reflect this change:
  
• Delete: Used to remove a node from the XML data. For example, the management of AdventureWorks has decided to remove the ‘City’ column from the customer details. You can write the following query to display the results:
  
  UPDATE CustomDetails SET Cust_Details.modify (‘delete (/Customer/@City) [1]’)

Retreive XML data using XQuery

Add 3 months in current month in asp.net

 <form id="form1" runat="server">
    <div>
   
        <asp:Button ID="Button1" runat="server" onclick="Button1_Click" Text="Click" BackColor="#99CCFF" />
   
    </div>
    <asp:Label ID="Label1" runat="server" BackColor="Yellow"></asp:Label>
    </form>
Code Behind
 protected void Button1_Click(object sender, EventArgs e)
    {
        {        
            DateTime now = DateTime.Now;        
            DateTime after3Months = now.AddMonths(3);
            Label1.Text = "now = " + now.ToLongDateString();
            Label1.Text += "<br /><br />after added 3 months to now= ";
            Label1.Text += after3Months.ToLongDateString();
        }

    }
Code Generate the following output

Example of Append string using StringBuilder class in asp.net

 <form id="form1" runat="server">
    <asp:Button ID="Button1"
     runat="server"
     onclick="Button1_Click"
     Text="Click"
        Width="74px" BackColor="#FF6666" />
    <div style="width: 93px">
   
        <asp:Label ID="Label1"
         runat="server"
         Text="Label" BackColor="Yellow" ForeColor="Black"></asp:Label>
   
    </div>
    </form>

 Code Behind

 protected void Button1_Click(object sender, System.EventArgs e)  

       {

        StringBuilder stringA = new StringBuilder();

        stringA.Append("those are text. ");

        StringBuilder stringA2 = new StringBuilder(" another text.");

        stringA.Append(stringA2);

        Label1.Text = stringA.ToString(); 

    }

Code Generate the following output

How to Retrieve XML Data Using XQuery

In addition to FOR XML, SQL Server allows programmer to extract data stored in variables or columns with the XML data type by using XQuery. XQuery is a language that uses a set of statements and functions provided by the XML data type to extract data. As compared to the FOR XML clause of the SELECT statement, the XQuery statements allow you to extract specific parts of the XML data.

Each XQuery statement consists of two parts, prolog and body. In the prolog section, you declare the namespaces. In addition, schemas can be imported in the prolog. The body parts specifies the XML nodes to be retrieved. The XQuery language includes the following statements:

• For: Used to iterate through a set of nodes at the same level as in an XML document.
• Let: Used to declare variables and assign values.
• Order by: Used to specify a sequence.
• Where: Used to specify criteria for the data to be extracted.
• Return: Used to specify the XML returned from a statement.

The XQuery statements also use the following functions provided by the XML data type:

Query: Used to extract XML from an XML data type. The XML to be retrieved is bicycle is manufactured at AdventureWorks, it passes through a series of work centre locations. Each work centre location produces a different cycle component. Therefore, the number of production steps varies between different work centres.

To analyse the production process, the management of AdventureWorks needs to retrieve a list of the location IDs of all the work centers, which have more than four steps. You need to generate the list displaying the location ids in the ascending order of the steps included in the work centres.

To perform this task, the database developer can create the following query:

SELECT Instructons.query
(‘ declare namespace
ns=http://schemas.microsoft.com/sqlserver/2004/07/adventure-works/ProductModelManuInstructions:
for $work in /ns:root/ns:Location
where count(#work/ns:step) > 4
order by count ($work/ns:step)
return
count($work/ns:step)’) AS Result
FROM Production.ProductModel
WHERE Instructions IS NOT NULL

Value: Used to return a single value from an XML document. To extract a single value, you need to specify an XQuery expression that identifies a single node and a data type of the value to be retrieved.

For example, the management of AventureWorks, Ins. Wants a list containing the product model id, product name, machine hours, and labour hours. However, not all product have production instructions. As a database developer, you have stored this data in the XML format in the ProductModel table. You can create the following query to display the results:

SELECT ProductModelID, Name, Instructions.value (‘declare namespace ns=”http//schemas.microsoft.com/sqlserver/2004/07/adventure-works/ProductManuInstructions”;
(/ns:root/ns:Location/@LaborHours) [1]’, ‘float’)AS
LaborHours,
Instructions.value(declare namespace
Ns=”http://schemas.microsoft.com/sqlserver/2004/07/adventure-works/ProductModelManuInstructions”;
(/ns:root/ns:Location/@MachineHours) [1]’, ‘float’) AS MachineHours
FROM Production.ProductModel
WHERE Instructions IS NOT NULL

Exist: Used to check the existence of a node in an XML data. The function returns I if the specified node exists else it returns 0. For example, the management of AdventureWorks, wants the details of all the customers in the city ‘NJ’. The details of all the customers are stored in an XML format in the CustDetails table. You can use the following query to display the results:

SELECT Cust_ID, Cust_Details.exist
(‘Customer[@City=’NJ”]’) AS ‘True’ FROM CustDetails

Retrieve XML data from DataSet

How to Define Methods with Behavior: Java

Objects have behavior that is implemented by its methods. Other objects can ask an object to do something by invoking its methods. This section tells you everything you need to know about writing methods for your Java classes.

In Java, you define a class’s methods in the body of the class for which the method implements some behavior. Typically, you declare a class’s methods after its variables in the class body although this is not required.

Implementing Methods

Similar to a class implementation, a method implementation consists of two parts: the method declaration and the method body

methodDeclaration {
        methodBody
}

The Method Declaration

At minimum, a method declaration has a name and a return type indicating the data type of the value returned by the method:

returnType methodName( ) {
. . .
}

This method declaration is very basic. Methods have many other attributes such as arguments, access control, and so on.

Objects as Instances of Class

A class defines only a blueprint and its concrete version comes into effect only through objects that implement the functionality as defined by class. Recall our class example of City class. The objects created from this class will have two variables: name and population; and they will be able to represent cities. The object of City class will also have a method namely display ( ). An object of a class is typically named by a variable of the class type. For example, the program CityTrial in Example 4.7 declares the two variables metl1 and metro2 to be of type City, as follows;

City metro1, metro2;

This gives us variables of the class City, but so far there are no objects of the class. Objects are class value that are named by the variables. To obtain an object you must use the new operator to create a “new” object. For example, the following creates an object of the class City and names it with the variable metro1:

Metro = new city ( );

For now you need not go into details, simply note that the statement like:

Class-variable = new class-Name ( );

Creates a new object of the specified class and associates it with the class type variables. Since the class variable now names an object of the class, we will often refer to the class variable as an object of the class. (This is really the same usage as when we refer to an int variable n as “the integer n”, even though the integer is strictly speaking not n but the value of n.)

Unlike what we did in previous lines, the declaration of a class type variable and the creation of the object are more typically combined into one statement as follows:
City metro1 = new City( );

To instantiate an object, Java uses the keyword new.

Declare member variables in JAVA