CRUD Operations on Windows Azure table and Azure Storage

Objective

This article will give a walkthrough on how to perform a CRUD operation on Azure table.

Step 1

Creating the

Create a new Cloud Service Application. To create, File -> New -> Projects -> Cloud Services. Select ASP.Net Web Role. I am giving CRUDSample to the name of the project and CRUDWebRole to the name of the Web Role. After adding project, in solution explorer you can see two projects. One is project to publish in azure and other is simple asp.net project. In our case CRUDSample is project which contains configuration settings for azure and CRUDWebRole is asp.net project for development.

Step 2

Make sure below references are added CRUDWebRole projects.

System.Data.Service

System.Data.Service.Client

Microsoft.WindowsAzure.Diagnostics

Microsoft.WindowsAzure.ServiceRunTime

Microsoft.WindowsAzure.StorageClient.

Step 3

Creating Entity class

Now right click to asp.net project add a class which will model the table in azure. Give any name to this class. This class will act as entity table.

Inherit the class from
Microsoft.WindowsAzure.StorageClient.TableServiceEntity

Add a default constructor
In Default constructor initialize the Row key and Partition key
Properties of the class define columns of the table.

Row Key and Partition key

These two keys uniquely define a table and row in azure storage.

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

using System.Data.Services;

namespace CRUDWebRole

{

public
class
USTEntity : Microsoft.WindowsAzure.StorageClient.TableServiceEntity

{

public USTEntity()

{

RowKey = String.Format(“{0:10}_{1}”, (DateTime.MaxValue.Ticks – DateTime.Now.Ticks), Guid.NewGuid());

PartitionKey = “UST”;

}

public
String Name { get; set; }

public
String Id { get; set; }

public
String Manager { get; set; }

public
String Experience { get; set; }

public
String Technology { get; set; }

public
String Location { get; set; }}}

Step 4

Creating Context class.

Now right click on asp.net project and add a new class as context class. This class will contain function to perform all the CRUD operation. This class is inherited from TableServiceContext class.

In default constructor passes the base address and storage credentials to base class.
Since TableServiceContext
class performs the operations against a class which is implementing IQueryable interface, so we will implement the interface for the entity class.
Just write simple LINQ for other CRUD functions.

Entire class is as below

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

using Microsoft.WindowsAzure;

using Microsoft.WindowsAzure.StorageClient;

namespace CRUDWebRole

{

public
class
USTContext : TableServiceContext

{

public USTContext(string baseAddress, StorageCredentials credentials)

: base(baseAddress, credentials)

{

}

public IQueryable<USTEntity> USTEntities
{
get
{
return this.CreateQuery<USTEntity>(“USTEntities”);
}}

public void ADDUSociate(USTClientEntity entity)
{
this.AddObject(“USTEntities”, new
USTEntity {Name = entity.Name ,Manager =entity.Manager,Id =entity.Id,Location=entity.Location,Technology=entity.Technology,Experience=entity.Experience});
this.SaveChanges();
}
public
void DELUSociate(string id)

{

USTEntity res = (from r in USTEntities where r.Id == id select r ).First();

this.DeleteObject(res);
this.SaveChanges();}

public void UPDATEUSociate(USTClientEntity entity){
USTEntity res = (from r in USTEntities where r.Id == entity.Id select r).First();
res.Technology = entity.Technology;
res.Location = entity.Location;
res.Manager = entity.Manager;
res.Experience = entity.Experience;
this.UpdateObject(res);
this.SaveChanges();
}}}

In above code I have used USTClientEntity class. This class is mapping of Entity class. This class is as below

USTClientEntity.cs

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

namespace CRUDWebRole

{

public
class
USTClientEntity

{

public String Name { get; set; }

public String Id { get; set; }

public String Manager { get; set; }

public String Experience { get; set; }

public String Technology { get; set; }

public String Location { get; set; }

}}

Step 5

Working with connection strings

We have two options to work with

Use local development center
Use Azure table from Windows azure

Use Local Development center

This option will use the local storage created by development fabric controller when you install Azure SDK.

Go to Azure Project. In this case it is , CRUDSample
Click on Roles folder
Then click on CRUDWebRole
Click on setting tab and add connection string
Click on Add Setting
Make sure while adding connection string, you are choosing connection string from the drop down. Give any name to the string setting.
Now click on left corner button
To use local storage select the radio button Use Development Storage and click on OK button.
To use AZURE table setting

Account Name: Give Azure storage account name

Account Key: Give Primary key from azure storage

Leave other setting as default and press ok.

For My purpose I have two connection strings in my application.

DiagnosticConnectionString

And

CrudString

Step 6

Creating table

To create table in ASP.net project click on WebRole.cs class
And add below line of code to create class.

var account = CloudStorageAccount.FromConfigurationSetting(“CrudString”);

CloudTableClient.CreateTablesFromModel(typeof(USTContext), account.TableEndpoint.AbsoluteUri, account.Credentials);

Whole WebRole.Cs class will look like below ,

WebRole.cs

using System.Linq;

using Microsoft.WindowsAzure.Diagnostics;

using Microsoft.WindowsAzure.ServiceRuntime;

using System.Data.Services.Client;

using Microsoft.WindowsAzure;

using Microsoft.WindowsAzure.StorageClient;

namespace CRUDWebRole

{

public class WebRole : RoleEntryPoint
{
public override bool OnStart()
{
DiagnosticMonitor.Start(“DiagnosticsConnectionString”);

RoleEnvironment.Changing += RoleEnvironmentChanging;

CloudStorageAccount.SetConfigurationSettingPublisher((configName, configSetter) =>

{

configSetter(RoleEnvironment.GetConfigurationSettingValue(configName));

RoleEnvironment.Changed += (anotherSender, arg) =>

{

if (arg.Changes.OfType<RoleEnvironmentConfigurationSettingChange>()

.Any((change) => (change.ConfigurationSettingName == configName)))

{

if (!configSetter(RoleEnvironment.GetConfigurationSettingValue(configName)))

{

RoleEnvironment.RequestRecycle();

}

};});

var account = CloudStorageAccount.FromConfigurationSetting(“CrudString”);
CloudTableClient.CreateTablesFromModel(typeof(USTContext), account.TableEndpoint.AbsoluteUri, account.Credentials);
return base.OnStart();
}
private void RoleEnvironmentChanging(object sender, RoleEnvironmentChangingEventArgs e)

{

if (e.Changes.Any(change => change is
RoleEnvironmentConfigurationSettingChange))

{

// Set e.Cancel to true to restart this role instance

e.Cancel = true;

}}}}

Here CrudString is name of the connection string.

Step 7

CRUD Operations

To add a record

var account = CloudStorageAccount.FromConfigurationSetting(“CrudString”);

var context = new
USTContext(account.TableEndpoint.ToString(), account.Credentials);

USTClientEntity entity = new
USTClientEntity(){Id= txtEmployeeID.Text.ToString(),Name = txtEmployeeName.Text.ToString(),Manager=txtManagerName.Text.ToString(),Experience=ddlExperience.Text.ToString(), Technology = ddlTechnology.Text.ToString(),Location = ddlCurrentLocation.Text.ToString()};

context.ADDUSociate(entity);

To update a record

entity = new
USTClientEntity() {Id=ddlEmployees.SelectedItem.Text , Manager = txtManagerName.Text, Location = ddlCurrentLocation.SelectedItem.Text, Technology = ddlTechnology.SelectedItem.Text, Experience = ddlExperience.SelectedItem.Text };

var account = CloudStorageAccount.FromConfigurationSetting(“CrudString”);

var context = new
USTContext(account.TableEndpoint.ToString(), account.Credentials);

context.UPDATEUSociate(entity);

To Delete a record

var account = CloudStorageAccount.FromConfigurationSetting(“CrudString”);

var context = new
USTContext(account.TableEndpoint.ToString(), account.Credentials);

if(!string.IsNullOrEmpty(ddlEmployees.Text.ToString()))

{

context.DELUSociate(ddlEmployees.Text.ToString());

}

To View all records

var account = CloudStorageAccount.FromConfigurationSetting(“CrudString”);

var context = new
USTContext(account.TableEndpoint.ToString(), account.Credentials);

List<USTClientEntity> lst = new
List<USTClientEntity>();

foreach (USTEntity u in context.USTEntities)

{

if (!string.IsNullOrEmpty(u.Id))

{

lst.Add(new
USTClientEntity() { Id = u.Id, Name = u.Name, Manager = u.Manager, Experience = u.Experience, Location = u.Location, Technology = u.Technology });

}

this.grdViewAll.DataSource = lst;

this.grdViewAll.DataBind();

In all above cases drodownlist , Textboxes and GridView has been used as input and output control.

Now your application Is ready to run. Thanks for reading.

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Dhananjay Kumar

Developer Evangelist @Infragistics | MVP @Microsoft | Organizer ng-India, India Angular Conference