Create or Delete Database Via LINQ-to-SQL

Vijay Prativadi
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Introduction

This article demonstrates an interesting and very useful concept in LINQ-to-SQL.

Question: What is creating and deleting database via LINQ-to-SQL?

In simple terms "It provides the flexibility to create or delete data dynamically. The database can be created with a table as determined by user-defined requirements".

Step 1: Create a new web application

Step 2: Adding new LINQ-to-SQL

Step 3: The complete code of DataClasses1.designer.cs is as in the following:

#pragma warning disable 1591
//------------------------------------------------------------------------------
// <auto-generated>
// This code was generated by a tool.
// Runtime Version:4.0.30319.17929
//
// Changes to this file may cause incorrect behavior and will be lost if
// the code is regenerated.
// </auto-generated>
//------------------------------------------------------------------------------
namespace Create_Delete_DB_LINQtoSQL
{
    using System.Data.Linq;
    using System.Data.Linq.Mapping;
    using System.Data;
    using System.Collections.Generic;
    using System.Reflection;
    using System.Linq;
    using System.Linq.Expressions;
    using System.ComponentModel;
    using System;
    public partial class DataClasses1DataContext : System.Data.Linq.DataContext
    {
        public Table<Employee> Employees;
        private static System.Data.Linq.Mapping.MappingSource mappingSource = new AttributeMappingSource();
        #region Extensibility Method Definitionspartial void OnCreated();
        #endregion
        public DataClasses1DataContext(string connection): base(connection, mappingSource)
        {
            OnCreated();
        }
        public DataClasses1DataContext(System.Data.IDbConnection connection): base(connection, mappingSource)
        {
            OnCreated();
        }
        public DataClasses1DataContext(string connection, System.Data.Linq.Mapping.MappingSource mappingSource): base(connection, mappingSource)
        {
            OnCreated();
        }
        public DataClasses1DataContext(System.Data.IDbConnection connection, System.Data.Linq.Mapping.MappingSource mappingSource): base(connection, mappingSource)
        {
            OnCreated();
        }
        [Table(Name = "tblEmployee")]
        public class Employee
        {
            [Column(IsPrimaryKey = true)]public int Id;
            [Column]public string FirstName;
            [Column]public string LastName;
            [Column]public int Age;
        }
    }
}
#pragma warning restore 1591

Step 4: The complete code of WebForm1.aspx is as in the following:

<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="WebForm1.aspx.cs" Inherits="Create_Delete_DB_LINQtoSQL.WebForm1" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head id="Head1" runat="server">
    <title></title>
</head>
<body>
    <form id="form1" runat="server">
        <center>
            <div>
                <table>
                    <tr>
                        <td colspan="4" align="center">
                            <asp:Label ID="Label1" runat="server" Text="Create | Delete DB via LINQ-to-SQL" Font-Bold="true" Font-Size="Large" Font-Names="Verdana"
ForeColor="Maroon"></asp:Label></td>
                    </tr>
                    <tr>
                        <td colspan="3" align="center">
                            <asp:Label ID="Label2" runat="server" Text="Please Enter DB Name" Font-Bold="true" Font-Names="Verdana"></asp:Label></td>
                        <td colspan="3" align="center">
                            <asp:TextBox ID="TextBox1" runat="server"></asp:TextBox></td>
                    </tr>
                    <tr>
                        <td colspan="2" align="center">
                            <asp:Button ID="Button1" runat="server" Text="Create DB" Font-Names="Verdana" Width="213px" BackColor="Orange" Font-Bold="True" OnClick="Button1_Click" /></td>
                        <td colspan="2" align="center">
                            <asp:Button ID="Button2" runat="server" Text="Delete DB" Font-Names="Verdana" Width="213px" BackColor="Orange" Font-Bold="True" OnClick="Button2_Click" /></td>
                    </tr>
                    <tr>
                        <td colspan="4" align="center">
                            <asp:Label ID="Label3" runat="server" Font-Bold="true" Font-Names="Verdana"></asp:Label></td>
                    </tr>
                </table>
            </div>
        </center>
    </form>
</body>
</html>

Step 5: The complete code of WebForm1.aspx.cs is as in the following:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
namespace Create_Delete_DB_LINQtoSQL
{
    public partial class WebForm1 : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e) { }
        protected void Button1_Click(object sender, EventArgs e)
        {
            if (string.IsNullOrEmpty(TextBox1.Text))
            {
                Label3.Text = "Please Enter DB Name";
                Label3.ForeColor = System.Drawing.Color.Red;
            }
            else
            {
                DataClasses1DataContext objContext = new DataClasses1DataContext(@"c:\" + TextBox1.Text + ".mdf");
                objContext.CreateDatabase();
                Label3.Text = "DB Creation Successful";
                Label3.ForeColor = System.Drawing.Color.Green;
                TextBox1.Text = string.Empty;
            }
        }
        protected void Button2_Click(object sender, EventArgs e)
        {
            if (string.IsNullOrEmpty(TextBox1.Text))
            {
                Label3.Text = "Please Enter DB Name";
                Label3.ForeColor = System.Drawing.Color.Red;
            }
            else
            {
                DataClasses1DataContext objContext = new DataClasses1DataContext(@"c:\" + TextBox1.Text + ".mdf");
                objContext.DeleteDatabase();
                Label3.Text = "DB Deletion Successful";
                Label3.ForeColor = System.Drawing.Color.Green;
                TextBox1.Text = string.Empty;
            }
        }
    }
}

Step 6: The output of the application is as in the following:

Step 7: The created database output of the application is as in the following:

Step 8: The deleted database output of the application is as in the following:

I hope this article was useful for you.

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