Understanding Data Management
Almost every piece of software ever written works with data. In fact, a typical web application is often just a thin user interface shell on top of sophisticated data-driven code that reads and writes information from a database. Often, website users aren’t aware (or don’t care) that the displayed information originates from a database. They just want to be able to search your product catalog, place an order, or check their payment records.
The Role of the Database The most common way to manage data is to use a database. Database technology is particularly useful for business software, which typically requires sets of related information. For example, a typical database for a sales program consists of a list of customers, a list of products, and a list of sales that draws on information from the other two tables. This type of information is best described using a relational model, which is the philosophy that underlies all modern database products, including SQL Server, Oracle, and even Microsoft Access.
As you probably know, a relational model breaks information down to its smallest and most concise units. For example, a sales record doesn’t store all the information about the products that were sold. Instead, it stores just a product ID that refers to a full record in a product table.
Although it’s technically possible to organize data into tables and store it on the hard drive in one or more files (perhaps using a standard like XML), this approach wouldn’t be very flexible. Instead, a web application needs a full relational database management system (RDBMS), such as SQL Server. The RDBMS handles the data infrastructure, ensuring optimum performance and reliability. For example, the RDBMS takes the responsibility of providing
data to multiple users simultaneously, disallowing invalid data, and ommitting groups of actions at once using transactions.
In most ASP.NET applications, you’ll need to use a database for some tasks. Here are some basic examples of data at work in a web application:
• E-commerce sites (like Amazon) use detailed databases to store product catalogs. They also track orders, customers, shipment records, and inventory information in a huge arrangement of related tables.
• Search engines (like Google) use databases to store indexes of page URLs, links, and keywords.
• Knowledge bases (like Microsoft Support) use less structured databases that store vast quantities of information or links to various documents and resources.
• Media sites (like The New York Times) store their articles in databases.
Important Considerations of Velocity (Powershell Command)
When using the PowerShell commands described in this topic, it is important to consider the following points:
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The security identity of the person using these PowerShell commands must have administrator privileges on all cache servers in the cache cluster.
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Parameter values for the commands are case sensitive. For example, if you create a cache called
NamedCache1, the commandGet-CacheConfig -CacheName namedcache1will not work. You must match the case, as inGet-CacheConfig -CacheName NamedCache1. -
When making XML-based cluster configuration changes with the
Export-CacheClusterConfigandImport-CacheClusterConfigcommands, you can change cluster configuration settings (XML attributes) in the XML file, but adding or removing named caches and cache hosts by inserting or removing XML elements is not supported. -
Start-CacheCluster,Stop-CacheCluster, andRestart-CacheClustercache cluster commands involve coordinating the state of the cache host Windows service on all cache servers in the cluster. These commands may take longer when lead hosts perform the cluster management role; there must be a majority of lead host running while the rest of the cache hosts stop and start. -
Stop-CacheClusterorRestart-CacheClustercache cluster commands cause all data to be flushed from the memory of all cache hosts in the cluster. -
Set-CacheConfigandImport-CacheClusterConfigcommands require you to restart the cache cluster with Restart-CacheCluster in order for changes to take effect. -
Remove-CacheandNew-Cachecommands can be used to change a named cache configuration without impacting other named caches in the cluster.
How to install an additional cache server and join it to the cache cluster
Confirm hardware and software requirements and install pre-requisites on the cache server. For more information, see the "Velocity" download page.
Download the "Velocity" installation program from the "Velocity" download page and copy it to the cache server. There are two installation programs available:
MicrosoftDistributedCache-i386.exe: Use this program to install "Velocity" on 32-bit computers.
MicrosoftDistributedCache-amd64.exe: Use this program to install "Velocity" on x64-based computers.
Perform the cache server installation using the setting of the cache cluster you want the cache server to join. This can be done manually with the graphical user interface (GUI) or by using command-line parameters to automate a "silent" installation. For more information about a cache server installation, see Cache Server Installation (Velocity).
GUI installation: To begin the GUI installation, double-click on the installation program.
Automated installation: To perform an automated installation, open the CMD.exe command-line tool and navigate to the folder within which you saved the installation program. Then, execute the installation program using the automation parameters. For more information, see Automated Cache Server Installation (Velocity).
Open the PowerShell-based cache administration tool from the shortcut that was installed on the desktop of the cache server. Note: On Microsoft Windows Vista and Microsoft Windows Server 2008 operating systems, you will have to right-click the "Velocity" PowerShell shortcut and select Run as administrator for the cache administration tool to work correctly.
Set the PowerShell execution policy for signed assemblies, this is required to run the cache administration cmdlets. Depending on how your cache server is configured, you may not be prompted to set the policy. Follow the prompt or set the policy manually using the command: Set-ExecutionPolicy -ExecutionPolicy AllSigned
Join the cache server to the cache cluster using the Start-CacheHost command. For example, if you performed the cache server installation on a computer named CacheServer1 with the default values for the TCP/IP port numbers, you would use the following command to start the server's cache host service: Start-CacheHost -HostName CacheServer1 -CachePort 22233. For more information about the cache administration commands available, see Cache Administration with PowerShell (Velocity).
Posted in: .Net Programming| Tags: .net .net 4.0 CTP CTP 3 Distribute Cache Install VelocityHow to install "Velocity" for the first time
Determine how you will store the cluster configuration settings. For more information, see Cluster Configuration Storage Options (Velocity).
Prepare the cluster configuration storage location and assign the necessary security permissions to the security identity of the person or account performing the installation.
For more information about preparing a SQL Server-based cluster configuration, see How to: Prepare a SQL Server Database for Cluster Configuration Settings (Velocity).
For more information about preparing a shared folder, see How to: Prepare a Shared Network Folder for Cluster Configuration Settings (Velocity).
Confirm hardware and software requirements and install pre-requisites on the cache server. For more information, see the "Velocity" download page.
Download the Microsoft project code named "Velocity" installation program from the "Velocity" download page and copy it to the cache server. There are two installation programs available:
MicrosoftDistributedCache-i386.exe: Use this program to install "Velocity" on 32-bit computers.
MicrosoftDistributedCache-amd64.exe: Use this program to install "Velocity" on x64-based computers.
Perform the cache server installation. For more information, see Cache Server Installation (Velocity). This can be done manually with the graphical user interface (GUI) or by using command-line parameters to automate a "silent" installation.
GUI installation: To begin the GUI installation, double-click on the installation program.
Automated installation: To perform an automated installation, open the CMD.exe command-line tool and navigate to the folder in which you saved the installation program. Then, execute the installation program using the automation parameters. For more information, see Automated Cache Server Installation (Velocity).
Open the PowerShell-based cache administration tool from the shortcut that was installed on the desktop of the cache server. Note: On Microsoft Windows Vista and Microsoft Windows Server 2008 operating systems, you will have to right-click the "Velocity" PowerShell shortcut and select Run as administrator for the cache administration tool to work correctly.
Set the PowerShell execution policy for signed assemblies, this is required to run the cache administration cmdlets. Depending on how your cache server is configured, you may be prompted to set the policy. Follow the prompt or set the policy manually using the command: Set-ExecutionPolicy -ExecutionPolicy AllSigned
Start the cache cluster using the command Start-CacheCluster. For more information about the cache administration commands available, see Cache Administration with PowerShell (Velocity).
(optional) To create your first cache, named FirstCache, use the command New-Cache FirstCache. For more information about cache settings, see the Cache Settings section in Cluster Configuration Settings (Velocity).
Install the cache client assemblies on the "Velocity" development environment or cache-enabled application server. For more information, see Installing Cache Client Assemblies (Velocity).
Posted in: .Net Programming| Tags: .net .net 4.0 CTP CTP 3 Distribute Cache Velocity