Q. Most Popular SQL Server Interview Questions and Answer?

1. Return Employee Records with Max salary

Ans.
        Select * from employee where salary=(select max(salary) from employee)
2. Return Highest salary in employee table

Ans. 
      Select max(salary) from employee
3. Return second highest salary in employee table 

Ans.
     select max(salary) from employee where salary not in (select max(salary) from employee) 
4. Return range of employee based on id

Ans.
     select * from employee where employee_id between 2003 and 2008
5. Return Employee Name,Highest salary and Departments 

Ans.
     select e.first_name,e.last_name,e.salary,d.department_name from employee e inner join department d on e.department_id=d.department_id where e.salary in(select max(salary) from employee)
6. Return highest salary ,employee_name,department_name for each department 

Ans.
     Select e.first_name,e.last_name,e.salary,d.department_name from employee e inner join department d on e.department_id=d.department_id where salary IN(select max(salary) from employee group by department_id )

How to add new column in existing table using sql server?

Ans.
Syntax:-

Alter Table [Table_Name] Alter Column [Column_Name] varchar(12)

Example:-

Alter table Table1 Alter Column Adddress varchar(50)

How to change schema of Tables in sql sever?

Ans.

Syntax:-

alter schema [new_schema] transfer [old_schema].[object_name];

Examples

Alter schema dbo transfer sys.table1

How to Alter "FOREIGN KEY" in existing table?

Ans.


ALTER TABLE [dbo].[Table2]  WITH CHECK ADD FOREIGN KEY([Dept_Id])
REFERENCES [dbo].[Table1] ([Dept_Id])

Q. How to bind treeview with database using asp.net C#?

Step 1.Create two table named VehicleTypes and VehicleSubTypes and insert some record?

CREATE TABLE [dbo].[VehicleTypes](
[ID] [int] IDENTITY(1,1) NOT NULL,
[Name] [varchar](50) NULL,
 CONSTRAINT [PK_VehicleTypes] PRIMARY KEY CLUSTERED
(
[ID] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY]


-----------------------------------

CREATE TABLE [dbo].[VehicleSubTypes](
[ID] [int] IDENTITY(1,1) NOT NULL,
[Name] [varchar](50) NULL,
[VehicleTypeId] [int] NULL,
 CONSTRAINT [PK_VehicleSubTypes] PRIMARY KEY CLUSTERED
(
[ID] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY]

ALTER TABLE [dbo].[VehicleSubTypes]  WITH CHECK ADD  CONSTRAINT [FK_VehicleSubTypes_VehicleSubTypes] FOREIGN KEY([VehicleTypeId])
REFERENCES [dbo].[VehicleTypes] ([ID])
GO
ALTER TABLE [dbo].[VehicleSubTypes] CHECK CONSTRAINT [FK_VehicleSubTypes_VehicleSubTypes]

-----------------------------------------------------------------

INSERT [dbo].[VehicleTypes] ([ID], [Name]) VALUES (1, N'Cars')
INSERT [dbo].[VehicleTypes] ([ID], [Name]) VALUES (2, N'Bikes')
INSERT [dbo].[VehicleTypes] ([ID], [Name]) VALUES (3, N'Heavy Vehicle')
-----------------------------------------------------------------

INSERT [dbo].[VehicleSubTypes] ([ID], [Name], [VehicleTypeId]) VALUES (1, N'Alto', 1)
INSERT [dbo].[VehicleSubTypes] ([ID], [Name], [VehicleTypeId]) VALUES (2, N'WagnoR', 1)
INSERT [dbo].[VehicleSubTypes] ([ID], [Name], [VehicleTypeId]) VALUES (3, N'Scorpio', 1)
INSERT [dbo].[VehicleSubTypes] ([ID], [Name], [VehicleTypeId]) VALUES (4, N'Duster', 1)
INSERT [dbo].[VehicleSubTypes] ([ID], [Name], [VehicleTypeId]) VALUES (5, N'Avenger', 2)
INSERT [dbo].[VehicleSubTypes] ([ID], [Name], [VehicleTypeId]) VALUES (6, N'Dicover', 2)
INSERT [dbo].[VehicleSubTypes] ([ID], [Name], [VehicleTypeId]) VALUES (7, N'Unicorn', 2)
INSERT [dbo].[VehicleSubTypes] ([ID], [Name], [VehicleTypeId]) VALUES (8, N'Karizma', 2)
INSERT [dbo].[VehicleSubTypes] ([ID], [Name], [VehicleTypeId]) VALUES (9, N'Hero', 2)
INSERT [dbo].[VehicleSubTypes] ([ID], [Name], [VehicleTypeId]) VALUES (10, N'Palatina', 2)
INSERT [dbo].[VehicleSubTypes] ([ID], [Name], [VehicleTypeId]) VALUES (11, N'Maruti Suzuki', 1)
INSERT [dbo].[VehicleSubTypes] ([ID], [Name], [VehicleTypeId]) VALUES (12, N'Truck', 3)
INSERT [dbo].[VehicleSubTypes] ([ID], [Name], [VehicleTypeId]) VALUES (13, N'Luxery Buses', 3)
SET IDENTITY_INSERT [dbo].[VehicleSubTypes] OFF
SET IDENTITY_INSERT [dbo].[VehicleTypes] ON


Step 2. Now open visual studio and create aspx page.

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="TreeView.aspx.cs" Inherits="TreeView" %>

<!DOCTYPE html>

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title></title>
 

    <style type="text/css">
        .nodeLevel1
        {
            font:40px Arial,Sans-Serif;
        }
        .nodeLevel2
        {
            font:20px Arial,Sans-Serif;
        }
        .nodeLevel3
        {
            font:10px Arial,Sans-Serif;
        }     
       
        .treeNode
        {
            transition: all .3s;
            padding: 12px 5px;
            text-align: left;
            /*width: 100%;*/
            margin: 0;
            min-width: 250px !important;
            border: 2px solid #8e44ad;
            text-decoration:none !important;
            color:black;
            /*color:blue;
            font:14px Arial, Sans-Serif;*/
        }
     .rootNode
        {
            font-size:18px;
            /*width:100%;*/
            border-bottom:Solid 1px black;
            color:#337ab7;
        }
     .leafNode {
            border: Dotted 2px black;
            padding: 10px;
            background-color: #eeeeee;
            font-weight: bold;
        }
     .selectNode
     {
        background-color:white;
        border:Dotted 2px black;
        font-weight:bold;
        color:#fff;
     }
    </style>
</head>
<body>
    <form id="form1" runat="server">
        <h3>Vehicle Details</h3>
        <hr />
        <asp:TreeView ID="TreeView1" runat="server" ImageSet="XPFileExplorer" NodeIndent="15"  NodeStyle-CssClass="treeNode"
    RootNodeStyle-CssClass="rootNode" ExpandDepth="1"  Font-Size="Small" HoverNodeStyle-CssClass="nodeLevel2"
    LeafNodeStyle-CssClass="leafNode" SelectedNodeStyle-CssClass="selectNode">

            <LevelStyles>
                <asp:TreeNodeStyle CssClass="nodeLevel1" />
                <asp:TreeNodeStyle CssClass="nodeLevel2" />
                <asp:TreeNodeStyle CssClass="nodeLevel3" />
                <asp:TreeNodeStyle CssClass="AspNet-TreeView-Collapse" />
                <asp:TreeNodeStyle CssClass="AspNet-TreeView-Expand" />
            </LevelStyles>

            <HoverNodeStyle Font-Underline="True" ForeColor="#6666AA" />
            <NodeStyle Font-Names="Tahoma" Font-Size="8pt" ForeColor="Black" HorizontalPadding="2px"
                NodeSpacing="0px" VerticalPadding="2px"></NodeStyle>
            <ParentNodeStyle Font-Bold="False" />
            <SelectedNodeStyle BackColor="#B5B5B5" Font-Underline="False" HorizontalPadding="0px" VerticalPadding="0px" />
        </asp:TreeView>
    </form>
</body>
</html>

step 3. now write c# code into code behind 

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

using System.Web.UI;

using System.Web.UI.WebControls;

using System.Data;

using System.Data.SqlClient;

using System.Configuration;

public partial class TreeView : System.Web.UI.Page

{

    protected void Page_Load(object sender, EventArgs e)

    {

        if (!this.IsPostBack)

        {

            DataTable dt = this.GetData("SELECT Id, Name FROM VehicleTypes");

            this.PopulateTreeView(dt, 0, null);

        }

    }

    private void PopulateTreeView(DataTable dtParent, int parentId, TreeNode treeNode)

    {

        foreach (DataRow row in dtParent.Rows)

        {

            TreeNode child = new TreeNode

            {

                Text = row["Name"].ToString(),

                Value = row["Id"].ToString()

            };

            if (parentId == 0)

            {

                TreeView1.Nodes.Add(child);

                DataTable dtChild = this.GetData("SELECT Id, Name FROM VehicleSubTypes WHERE VehicleTypeId = " + child.Value);

                PopulateTreeView(dtChild, int.Parse(child.Value), child);

            }

            else

            {

                treeNode.ChildNodes.Add(child);

            }

        }

    }

    private DataTable GetData(string query)

    {

        DataTable dt = new DataTable();

        string constr = ConfigurationManager.ConnectionStrings["constr"].ConnectionString;

        using (SqlConnection con = new SqlConnection(constr))

        {

            using (SqlCommand cmd = new SqlCommand(query))

            {

                using (SqlDataAdapter sda = new SqlDataAdapter())

                {

                    cmd.CommandType = CommandType.Text;

                    cmd.Connection = con;

                    sda.SelectCommand = cmd;

                    sda.Fill(dt);

                }

            }

            return dt;

        }

    }

} 

OutPut.

Q. Update ,Insert,Delete Operation with FormView Using asp.net?

Step 1  . Create table name as Employee.

CREATE TABLE [dbo].[Employee](
[EmpID] [int] IDENTITY(1,1) NOT NULL,
[LastName] [nvarchar](20) NOT NULL,
[FirstName] [nvarchar](10) NOT NULL,
[Address] [nvarchar](60) NULL,
[Country] [nvarchar](15) NULL,
[Designation] [nvarchar](30) NULL,
PRIMARY KEY CLUSTERED
(
[EmpID] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY]

GO

Step 2. Insert Some record manual like below

SET IDENTITY_INSERT [dbo].[Employee] ON

INSERT [dbo].[Employee] ([EmpID], [LastName], [FirstName], [Address], [Country], [Designation]) VALUES (1, N'Firoz', N'Ansari', N'Hyderabad', N'India', N'Developer')
INSERT [dbo].[Employee] ([EmpID], [LastName], [FirstName], [Address], [Country], [Designation]) VALUES (2, N'Ansari', N'Tamanna', N'Hyderabad', N'India', N'Developer')
INSERT [dbo].[Employee] ([EmpID], [LastName], [FirstName], [Address], [Country], [Designation]) VALUES (3, N'Singh', N'MK', N'Hyderabad', N'India', N'Developer')
SET IDENTITY_INSERT [dbo].[Employee] OFF

Step 3. Write Connection String Code inside web.config

<connectionStrings>
    <add name="constr" connectionString="Data Source=INDIA;Persist Security Info=False;Integrated Security=SSPI; Initial Catalog=Northwind;User Id=sa;Password=123;
        Connect Timeout=30;"/>
 
</connectionStrings>

Step 4. Now open visual studio and create aspx page

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="FormView.aspx.cs" Inherits="FormView" %>

<!DOCTYPE html>

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title></title>
    <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/4.7.0/css/font-awesome.min.css" />
    <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css" />
    <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
    <script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/js/bootstrap.min.js"></script>
    <link rel="stylesheet" href="https://cdn.datatables.net/1.10.16/css/dataTables.bootstrap4.min.css" />+
    <script src="https://cdn.datatables.net/1.10.16/js/jquery.dataTables.min.js" type="text/javascript"></script>
    <script src="https://cdn.datatables.net/1.10.16/js/dataTables.bootstrap4.min.js" type="text/javascript"></script>
</head>
<body>
    <form id="form1" runat="server">
        <div class="container py-3">
            <h2 class="text-center text-uppercase">Form View</h2>
            <div class="card">
                <asp:FormView ID="EmployeeFormView" DataKeyNames="EmpID" GridLines="Both" AllowPaging="true"
                    runat="server" OnItemDeleting="EmployeeFormView_ItemDeleting"
                    OnPageIndexChanging="EmployeeFormView_PageIndexChanging"
                    OnItemUpdating="EmployeeFormView_ItemUpdating"
                    OnItemInserted="EmployeeFormView_ItemInserted"
                    OnItemInserting="EmployeeFormView_ItemInserting"
                    OnItemUpdated="EmployeeFormView_ItemUpdated"
                    OnModeChanging="EmployeeFormView_ModeChanging" BackColor="#FFFF66"
                    BorderColor="#FF8080" EmptyDataText="Data not available">
                    <HeaderStyle BackColor="Navy" ForeColor="#999966" />
                    <RowStyle BackColor="White" ForeColor="#CC3300" />
                    <EditRowStyle BackColor="#66FF99" ForeColor="#FF9966" />
                    <ItemTemplate>
                        <table>
                            <tr>
                                <td align="left"><b>Employee ID:-&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp</b></td>
                                <td><%# Eval("EmpID") %></td>
                            </tr>
                            <tr>
                                <td align="left"><b>First Name:-&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp</b></td>
                                <td><%# Eval("FirstName") %></td>
                            </tr>
                            <tr>
                                <td align="left"><b>Last Name:-&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp</b></td>
                                <td><%# Eval("LastName") %></td>
                            </tr>
                            <tr>
                                <td align="left"><b>Address:-&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp</b></td>
                                <td><%# Eval("Address")%></td>
                            </tr>

                            <tr>
                                <td align="left"><b>Designation:-&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp</b></td>
                                <td><%# Eval("Country")%></td>
                            </tr>
                             <tr>
                                <td align="left"><b>Designation:-&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp</b></td>
                                <td><%# Eval("Designation")%></td>
                            </tr>
                            <tr>
                                <td colspan="2">
                                    <asp:LinkButton ID="EditButton" Text="Edit" CommandName="Edit" runat="server" />
                                    &nbsp;
                        <asp:LinkButton ID="NewButton" Text="New" CommandName="New" runat="server" />
                                    &nbsp;
                        <asp:LinkButton ID="DeleteButton" Text="Delete" CommandName="Delete" runat="server" />
                                </td>
                            </tr>
                        </table>
                    </ItemTemplate>
                    <EditItemTemplate>
                        <table>
                            <tr>
                                <td align="left"><b>Employee ID:</b></td>
                                <td>
                                    <asp:TextBox ID="txtEmployeeID2" Text='<%# Bind("EmpID") %>' runat="Server" /></td>
                            </tr>
                            <tr>
                                <td align="left"><b>First Name:</b></td>
                                <td>
                                    <asp:TextBox ID="txtFirstName2" Text='<%# Bind("FirstName") %>' runat="Server" /></td>
                            </tr>
                            <tr>
                                <td align="left"><b>Last Name:</b></td>
                                <td>
                                    <asp:TextBox ID="txtLastName2" Text='<%# Bind("LastName") %>' runat="Server" /></td>
                            </tr>
                            <tr>
                                <td align="left"><b>Address:</b></td>
                                <td>
                                    <asp:TextBox ID="txtAddress2" Text='<%# Bind("Address") %>' runat="Server" /></td>
                            </tr>
                            <tr>
                                <td align="left"><b>Country:</b></td>
                                <td>
                                    <asp:TextBox ID="txtCountry2" Text='<%# Bind("Country") %>' runat="Server" /></td>
                            </tr>
                               <tr>
                                <td align="left"><b>Designation:</b></td>
                                <td>
                                    <asp:TextBox ID="txtDesignation2" Text='<%# Bind("Designation") %>' runat="Server" /></td>
                            </tr>
                            <tr>
                                <td colspan="2">
                                    <asp:LinkButton ID="UpdateButton" Text="Update" CommandName="Update" runat="server" />
                                    &nbsp;
                        <asp:LinkButton ID="CancelUpdateButton" Text="Cancel" CommandName="Cancel" runat="server" />
                                </td>
                            </tr>
                        </table>
                    </EditItemTemplate>
                    <InsertItemTemplate>
                        <table>
                            <%--<tr>
                                <td align="right"><b>Employee ID:</b></td>
                                <td>
                                    <asp:TextBox ID="txtEmployeeID1" Text='<%# Bind("EmpID") %>' runat="Server" /></td>
                            </tr>--%>

                            <tr>
                                <td align="left"><b>First Name:</b></td>

                                <td>
                                    <asp:TextBox ID="txtFirstName1" Text='<%# Bind("FirstName") %>' runat="Server" /></td>
                            </tr>
                            <tr>
                                <td align="left"><b>Last Name:</b></td>

                                <td>
                                    <asp:TextBox ID="txtLastName1" Text='<%# Bind("LastName") %>' runat="Server" /></td>
                            </tr>
                            <tr>
                                <td align="left"><b>Address:</b></td>
                                <td>
                                    <asp:TextBox ID="txtAddress1" Text='<%# Bind("Address") %>' runat="Server" /></td>
                            </tr>
                            <tr>
                                <td align="left"><b>Country:</b></td>
                                <td>
                                    <asp:TextBox ID="txtCountry1" Text='<%# Bind("Country") %>' runat="Server" /></td>
                            </tr>
                               <tr>
                                <td align="left"><b>Designation:</b></td>
                                <td>
                                    <asp:TextBox ID="txtDesignation1" Text='<%# Bind("Designation") %>' runat="Server" /></td>
                            </tr>
                            <tr>
                                <td colspan="2">
                                    <asp:LinkButton ID="InsertButton" Text="Insert" CommandName="Insert" runat="server" />
                                    &nbsp;
                        <asp:LinkButton ID="CancelInsertButton" Text="Cancel" CommandName="Cancel" runat="server" />

                                </td>

                            </tr>

                        </table>

                    </InsertItemTemplate>
                </asp:FormView>
            </div>
        </div>
    </form>
</body>
</html>

Step 5. Now goto aspx.cs file and wrire the following code.

using System;

using System.Configuration;

using System.Data;

using System.Linq;

using System.Web;

using System.Web.Security;

using System.Web.UI;

using System.Web.UI.HtmlControls;

using System.Web.UI.WebControls;

using System.Web.UI.WebControls.WebParts;

using System.Xml.Linq;

using System.Data.SqlClient;

public partial class FormView : System.Web.UI.Page

{

    string connStr = ConfigurationManager.ConnectionStrings["constr"].ConnectionString;

    SqlDataAdapter sqlda = new SqlDataAdapter();

    SqlCommand com = new SqlCommand();

    DataTable dt;

    protected void Page_Load(object sender, EventArgs e)

    {

        if (!IsPostBack)

        {

            bindgrid();

        }

    }

    private void bindgrid()

    {

        SqlConnection conn = new SqlConnection(connStr);

        dt = new DataTable();

        com.Connection = conn;

        com.CommandText = "SELECT * FROM Employee";

        sqlda = new SqlDataAdapter(com);

        sqlda.Fill(dt);

        EmployeeFormView.DataSource = dt;

        EmployeeFormView.DataBind();        

    }

    protected void EmployeeFormView_PageIndexChanging(object sender, FormViewPageEventArgs e)

    {

        EmployeeFormView.PageIndex = e.NewPageIndex;

        bindgrid();

    }

    protected void EmployeeFormView_ItemDeleting(object sender, FormViewDeleteEventArgs e)

    {

        //string key = EmployeeFormView.DataKey["EmpID"].ToString();

        DataKey key = EmployeeFormView.DataKey;

        if (key.Value!=null)

        {

            SqlConnection conn = new SqlConnection(connStr);

            com.Connection = conn;

            com.CommandText = "DELETE FROM Employee WHERE EmpID='" + key+ "'";

            conn.Open();

            com.ExecuteNonQuery();

            conn.Close();

            Response.Write("Record deleted successfully");

            bindgrid();

        }

        else

        {

            Response.Write("Record not deleted");

        }

    }

    protected void EmployeeFormView_ItemUpdating(object sender, FormViewUpdateEventArgs e)

    {

      

        DataKey key = EmployeeFormView.DataKey;

        if (key.Value != null)

        {

            TextBox txtFirstName = (TextBox)EmployeeFormView.FindControl("txtFirstName2");

            TextBox txtLastName = (TextBox)EmployeeFormView.FindControl("txtLastName2");

            TextBox txtAddress = (TextBox)EmployeeFormView.FindControl("txtAddress2");

            TextBox txtCountry = (TextBox)EmployeeFormView.FindControl("txtCountry2");

            TextBox txtDesignation = (TextBox)EmployeeFormView.FindControl("txtDesignation2");

            SqlConnection conn = new SqlConnection(connStr);

            com.Connection = conn;

            com.CommandText = "UPDATE Employee SET FirstName ='" + txtFirstName.Text + "',LastName ='" + txtLastName.Text + "',Address ='" + txtAddress.Text + "',Country='" + txtCountry.Text + "',Designation='" + txtDesignation.Text + "' WHERE EmpID='" + key.Value.ToString() + "'";

            conn.Open();

            com.ExecuteNonQuery();

            Response.Write("Record updated successfully");

            bindgrid();

            conn.Close();

            txtFirstName.Text = "";

            txtLastName.Text = "";

            txtAddress.Text = "";

            txtCountry.Text = "";

            txtDesignation.Text = "";

        }

        else

        {

            Response.Write("Record not Updated");

        }

    }

    protected void EmployeeFormView_ModeChanging(object sender, FormViewModeEventArgs e)

    {

        EmployeeFormView.ChangeMode(e.NewMode);

        bindgrid();

        if (e.NewMode == FormViewMode.Edit)

        {

            EmployeeFormView.AllowPaging = false;

        }

        else

        {

            EmployeeFormView.AllowPaging = true;

        }

    }

    protected void EmployeeFormView_ItemInserted(object sender, FormViewInsertedEventArgs e)

    {

        EmployeeFormView.ChangeMode(FormViewMode.ReadOnly);

    }

    protected void EmployeeFormView_ItemUpdated(object sender, FormViewUpdatedEventArgs e)

    {

        EmployeeFormView.ChangeMode(FormViewMode.ReadOnly);

    }

    protected void EmployeeFormView_ItemInserting(object sender, FormViewInsertEventArgs e)

    {        

       

        TextBox txtFirstName = (TextBox)EmployeeFormView.FindControl("txtFirstName1");

        TextBox txtLastName = (TextBox)EmployeeFormView.FindControl("txtLastName1");

        TextBox txtAddress = (TextBox)EmployeeFormView.FindControl("txtAddress1");

        TextBox txtCountry = (TextBox)EmployeeFormView.FindControl("txtCountry1");

        TextBox txtDesignation = (TextBox)EmployeeFormView.FindControl("txtDesignation1");

        SqlConnection conn = new SqlConnection(connStr);

        com.Connection = conn;

        com.CommandText = "INSERT INTO Employee(FirstName,LastName,Address,Country,Designation) Values('" + txtFirstName.Text + "', '" + txtLastName.Text + "', '" + txtAddress.Text + "','" + txtCountry.Text+ "', '" + txtDesignation.Text + "')";

        conn.Open();

        com.ExecuteNonQuery();

        Response.Write("Record inserted successfully");

        bindgrid();

        conn.Close();

        txtFirstName.Text = "";

        txtLastName.Text = "";

        txtAddress.Text = "";

        txtCountry.Text = "";

        txtDesignation.Text = "";

    }   

}

Step 6.Now run the application the following page will appear.

Step 7.Whenever we will click on New link button then following page will come.

Note:- Form here you can enter some record and click on insert link button .

Step 8. Whenever click on Edit button then bellow page will apears.

Q. How to use detailsview is asp.net c# using sql server?

Step 1.Open SQL Server and create one table.

CREATE TABLE [dbo].[Customers](
[CustomerID] [nchar](5) NOT NULL,
[CompanyName] [nvarchar](40) NOT NULL,
[ContactName] [nvarchar](30) NULL,
[ContactTitle] [nvarchar](30) NULL,
[Address] [nvarchar](60) NULL,
[City] [nvarchar](15) NULL,
[Region] [nvarchar](15) NULL,
[PostalCode] [nvarchar](10) NULL,
[Country] [nvarchar](15) NULL,
[Phone] [nvarchar](24) NULL,
[Fax] [nvarchar](24) NULL,
 CONSTRAINT [PK_Customers] PRIMARY KEY CLUSTERED
(
[CustomerID] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY]

Step 2. Open visual studio and create one aspx page.

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="DetailsView.aspx.cs" Inherits="DetailsView" %>

<!DOCTYPE html>

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title></title>
    <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/4.7.0/css/font-awesome.min.css" />
    <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css" />
    <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
    <script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/js/bootstrap.min.js"></script>
    <link rel="stylesheet" href="https://cdn.datatables.net/1.10.16/css/dataTables.bootstrap4.min.css" />
    <script src="https://cdn.datatables.net/1.10.16/js/jquery.dataTables.min.js" type="text/javascript"></script>
    <script src="https://cdn.datatables.net/1.10.16/js/dataTables.bootstrap4.min.js" type="text/javascript"></script>
</head>
<body>
    <form id="form1" runat="server">
        <div class="container py-10">
            <h2 class="text-center text-uppercase">How to upload excel file in sql server database in asp.net</h2>
            <div class="card">
                <asp:DetailsView ID="DetailsView1" runat="server" DataKeyNames="CustomerID" CellPadding="6" ForeColor="#333333" AutoGenerateRows="false"
                    GridLines="None" AllowPaging="True" AutoGenerateDeleteButton="True" AutoGenerateEditButton="True" AutoGenerateInsertButton="True" OnItemDeleting="DetailsView1_ItemDeleting"
                    OnPageIndexChanging="DetailsView1_PageIndexChanging" OnItemInserting="DetailsView1_ItemInserting" OnItemUpdating="DetailsView1_ItemUpdating"
                    OnItemInserted="DetailsView1_ItemInserted" OnItemUpdated="DetailsView1_ItemUpdated" OnModeChanging="DetailsView1_ModeChanging1">
                    <FooterStyle BackColor="#5D7B9D" Font-Bold="True" ForeColor="White" />
                    <CommandRowStyle BackColor="#E2DED6" Font-Bold="True" />
                    <RowStyle BackColor="#F7F6F3" ForeColor="#333333" />
                    <FieldHeaderStyle BackColor="#E9ECF1" Font-Bold="True" />
                    <PagerStyle BackColor="#284775" ForeColor="White" HorizontalAlign="Center" />
                    <Fields>
                        <asp:TemplateField HeaderText="CustomerID" Visible="True" InsertVisible="True">
                            <ItemTemplate>
                                <asp:Label ID="CustomerIDLabel" Text='<%# Eval("CustomerID") %>' runat="server"></asp:Label>
                            </ItemTemplate>
                            <EditItemTemplate>
                                <asp:TextBox ID="EditCustomerID" runat="server" Text='<%# Bind("CustomerID") %>' MaxLength="10" />
                            </EditItemTemplate>
                            <InsertItemTemplate>
                                <asp:TextBox ID="InsertCustomerIDTextBox" runat="server" Text='<%# Bind("CustomerID") %>' MaxLength="10" />
                            </InsertItemTemplate>
                        </asp:TemplateField>
                        <asp:TemplateField HeaderText="CompanyName">
                            <ItemTemplate>
                                <asp:Label ID="CompanyNameLabel" runat="server" Text='<%# Bind("CompanyName") %>'></asp:Label>
                            </ItemTemplate>
                            <EditItemTemplate>
                                <asp:TextBox ID="EditCompanyNameTextBox" runat="server" Text='<%# Bind("CompanyName") %>' MaxLength="10" />
                            </EditItemTemplate>
                            <InsertItemTemplate>
                                <asp:TextBox ID="InsertCompanyNameTextBox" runat="server" Text='<%# Bind("CompanyName") %>' MaxLength="10" />
                            </InsertItemTemplate>
                        </asp:TemplateField>
                        <asp:TemplateField HeaderText="ContactName">
                            <ItemTemplate>
                                <asp:Label ID="ContactNameLabel" runat="server" Text='<%# Bind("ContactName") %>'></asp:Label>
                            </ItemTemplate>
                            <EditItemTemplate>
                                <asp:TextBox ID="EditContactNameTextBox" runat="server" Text='<%# Bind("ContactName") %>' MaxLength="10" />
                            </EditItemTemplate>
                            <InsertItemTemplate>
                                <asp:TextBox ID="InsertContactNameTextBox" runat="server" Text='<%# Bind("ContactName") %>' MaxLength="10" />
                            </InsertItemTemplate>
                        </asp:TemplateField>
                        <asp:TemplateField HeaderText="ContactTitle">
                            <ItemTemplate>
                                <asp:Label ID="ContactTitleLabel" runat="server" Text='<%# Bind("ContactTitle") %>'></asp:Label>
                            </ItemTemplate>
                            <EditItemTemplate>
                                <asp:TextBox ID="EditContactTitleTextBox" runat="server" Text='<%# Bind("ContactTitle") %>' MaxLength="10" />
                            </EditItemTemplate>
                            <InsertItemTemplate>
                                <asp:TextBox ID="InsertContactTitleTextBox" runat="server" Text='<%# Bind("ContactTitle") %>' MaxLength="10" />
                            </InsertItemTemplate>
                        </asp:TemplateField>
                        <asp:TemplateField HeaderText="Address">
                            <ItemTemplate>
                                <asp:Label ID="AddressLabel" runat="server" Text='<%# Bind("Address") %>'></asp:Label>
                            </ItemTemplate>
                            <EditItemTemplate>
                                <asp:TextBox ID="EditAddressTextBox" runat="server" Text='<%# Bind("Address") %>' MaxLength="10" />
                            </EditItemTemplate>
                            <InsertItemTemplate>
                                <asp:TextBox ID="InsertAddressTextBox" runat="server" Text='<%# Bind("Address") %>' MaxLength="10" />
                            </InsertItemTemplate>
                        </asp:TemplateField>
                        <asp:TemplateField HeaderText="City">
                            <ItemTemplate>
                                <asp:Label ID="CityLabel" runat="server" Text='<%# Bind("City") %>'></asp:Label>
                            </ItemTemplate>
                            <EditItemTemplate>
                                <asp:TextBox ID="EditCityTextBox" runat="server" Text='<%# Bind("City") %>' MaxLength="10" />
                            </EditItemTemplate>
                            <InsertItemTemplate>
                                <asp:TextBox ID="InsertCityTextBox" runat="server" Text='<%# Bind("City") %>' MaxLength="10" />
                            </InsertItemTemplate>
                        </asp:TemplateField>
                        <asp:TemplateField HeaderText="Region">
                            <ItemTemplate>
                                <asp:Label ID="RegionLabel" runat="server" Text='<%# Bind("Region") %>'></asp:Label>
                            </ItemTemplate>
                            <EditItemTemplate>
                                <asp:TextBox ID="EditRegionTextBox" runat="server" Text='<%# Bind("Region") %>' MaxLength="10" />
                            </EditItemTemplate>
                            <InsertItemTemplate>
                                <asp:TextBox ID="InsertRegionTextBox" runat="server" Text='<%# Bind("Region") %>' MaxLength="10" />
                            </InsertItemTemplate>
                        </asp:TemplateField>
                        <asp:TemplateField HeaderText="PostalCode">
                            <ItemTemplate>
                                <asp:Label ID="PostalCodeLabel" runat="server" Text='<%# Bind("PostalCode") %>'></asp:Label>
                            </ItemTemplate>
                            <EditItemTemplate>
                                <asp:TextBox ID="EditPostalCodeTextBox" runat="server" Text='<%# Bind("PostalCode") %>' MaxLength="10" />
                            </EditItemTemplate>
                            <InsertItemTemplate>
                                <asp:TextBox ID="InsertPostalCodeTextBox" runat="server" Text='<%# Bind("PostalCode") %>' MaxLength="10" />
                            </InsertItemTemplate>
                        </asp:TemplateField>
                        <asp:TemplateField HeaderText="Country">
                            <ItemTemplate>
                                <asp:Label ID="CountryLabel" runat="server" Text='<%# Bind("Country") %>'></asp:Label>
                            </ItemTemplate>
                            <EditItemTemplate>
                                <asp:TextBox ID="EditCountryTextBox" runat="server" Text='<%# Bind("Country") %>' MaxLength="10" />
                            </EditItemTemplate>
                            <InsertItemTemplate>
                                <asp:TextBox ID="InsertCountryTextBox" runat="server" Text='<%# Bind("Country") %>' MaxLength="10" />
                            </InsertItemTemplate>
                        </asp:TemplateField>
                        <asp:TemplateField HeaderText="Phone">
                            <ItemTemplate>
                                <asp:Label ID="PhoneLabel" runat="server" Text='<%# Bind("Phone") %>'></asp:Label>
                            </ItemTemplate>
                            <EditItemTemplate>
                                <asp:TextBox ID="EditPhoneTextBox" runat="server" Text='<%# Bind("Phone") %>' MaxLength="10" />
                            </EditItemTemplate>
                            <InsertItemTemplate>
                                <asp:TextBox ID="InsertPhoneTextBox" runat="server" Text='<%# Bind("Phone") %>' MaxLength="10" />
                            </InsertItemTemplate>
                        </asp:TemplateField>
                        <asp:TemplateField HeaderText="Fax">
                            <ItemTemplate>
                                <asp:Label ID="FaxLabel" runat="server" Text='<%# Bind("Fax") %>'></asp:Label>
                            </ItemTemplate>
                            <EditItemTemplate>
                                <asp:TextBox ID="EditFaxTextBox" runat="server" Text='<%# Bind("Fax") %>' MaxLength="10" />
                            </EditItemTemplate>
                            <InsertItemTemplate>
                                <asp:TextBox ID="InsertFaxTextBox" runat="server" Text='<%# Bind("Fax") %>' MaxLength="10" />
                            </InsertItemTemplate>
                        </asp:TemplateField>
                    </Fields>
                    <HeaderStyle BackColor="#5D7B9D" Font-Bold="True" ForeColor="White" />
                    <EditRowStyle BackColor="#999999" />
                    <AlternatingRowStyle BackColor="White" ForeColor="#284775" />
                </asp:DetailsView>
            </div>
        </div>
        <asp:Label ID="MessageLabel" runat="server"></asp:Label>
    </form>
</body>
</html>

Step 3.Now goto code behind and write the following code which is giving bellow.