barcode vb.net 2008 Detached objects in Visual C#

Creation USS Code 39 in Visual C# Detached objects

Detached objects
Code39 Generation In Visual C#.NET
Using Barcode generation for .NET Control to generate, create Code39 image in Visual Studio .NET applications.
www.OnBarcode.com
Read Code 39 In C#
Using Barcode recognizer for VS .NET Control to read, scan read, scan image in .NET framework applications.
www.OnBarcode.com
When a transaction completes and the data is written to the database, the persistent instances associated with the persistence manager still exist in memory. If the transaction was successful, the state of these instances has been synchronized with the database. In ORM implementations with process-scoped identity (see the following sections), the instances retain their association to the persistence manager and are still considered persistent. But in the case of NHibernate, these instances lose their association with the persistence manager when you Close() the ISession. Because they re no longer associated with a persistence manager, we refer to these objects as detached. Detached instances may no longer be guaranteed to be synchronized with database state; they re no longer under the management of NHibernate. But they still contain persistent data. It s possible, and common, for the application to retain a reference and update a detached object outside of a transaction and therefore without NHibernate tracking the changes. Fortunately, NHibernate lets you use these instances in a new transaction by reassociating them with a new persistence manager. After reassociation, they re considered persistent again. This feature has a deep impact on how multitiered applications may be designed. The ability to return objects from one transaction to the presentation
2D Generation In Visual C#
Using Barcode drawer for Visual Studio .NET Control to generate, create 2D image in VS .NET applications.
www.OnBarcode.com
UPC - 13 Generator In Visual C#
Using Barcode maker for VS .NET Control to generate, create EAN / UCC - 13 image in VS .NET applications.
www.OnBarcode.com
Working with persistent objects
ECC200 Printer In C#
Using Barcode creator for VS .NET Control to generate, create Data Matrix image in .NET framework applications.
www.OnBarcode.com
Drawing Barcode In Visual C#.NET
Using Barcode creation for .NET Control to generate, create Barcode image in VS .NET applications.
www.OnBarcode.com
layer and later reuse them in a new transaction is one of NHibernate s main selling points. We discuss this usage in the next chapter as an implementation technique for long-running application transactions. We also show you how to avoid the DTO (anti-) pattern by using detached objects in section 10.3.1. NHibernate also provides an explicit way of detaching instances: the Evict() method of the ISession. This method is typically used only for cache management (a performance consideration). It s not common to perform detachment explicitly. Rather, all objects retrieved in a transaction become detached when the ISession is closed or when they re serialized (if they re passed remotely, for example). NHibernate doesn t need to provide functionality for controlling detachment of subgraphs. Instead, the application can control the depth of the fetched subgraph (the instances that are currently loaded in memory) using the query language or explicit graph navigation. Then, when the ISession is closed, this entire subgraph (all objects associated with a persistence manager) becomes detached. Let s look at the different states again, but this time consider the scope of object identity.
PDF 417 Generation In Visual C#
Using Barcode creator for .NET framework Control to generate, create PDF417 image in .NET framework applications.
www.OnBarcode.com
Generating UPC-E In C#
Using Barcode generation for Visual Studio .NET Control to generate, create UPC - E0 image in .NET applications.
www.OnBarcode.com
The scope of object identity
Code 3/9 Recognizer In Visual C#
Using Barcode decoder for VS .NET Control to read, scan read, scan image in VS .NET applications.
www.OnBarcode.com
Code 39 Extended Reader In Visual Basic .NET
Using Barcode reader for .NET Control to read, scan read, scan image in Visual Studio .NET applications.
www.OnBarcode.com
As application developers, we identify an object using .NET object identity (a==b). If an object changes state, is its .NET identity guaranteed to be the same in the new state In a layered application, that may not be the case. In order to explore this topic, it s important to understand the relationship between .NET identity, object.ReferenceEquals(a,b), and database identity, a.Id==b.Id. Sometimes they re equivalent; sometimes they aren t. We refer to the conditions under which .NET identity is equivalent to database identity as the scope of object identity. For this scope, there are three common choices:
Print ECC200 In Java
Using Barcode maker for Android Control to generate, create Data Matrix image in Android applications.
www.OnBarcode.com
2D Creation In .NET Framework
Using Barcode drawer for .NET Control to generate, create Matrix Barcode image in .NET applications.
www.OnBarcode.com
A primitive persistence layer with no identity scope makes no guarantees that if a row is accessed twice, the same .NET object instance will be returned to the application. This becomes problematic if the application modifies two different instances that both represent the same row in a single transaction (how do you decide which state should be propagated to the database ). A persistence layer using transaction-scoped identity guarantees that, in the context of a single transaction, only one object instance represents a particular database row. This avoids the previous problem and also allows for some caching to be done at the transaction level. Process-scoped identity goes one step further and guarantees that there is only one object instance representing the row in the whole process (.NET CLR).
UPC-A Supplement 5 Reader In .NET
Using Barcode decoder for .NET framework Control to read, scan read, scan image in .NET applications.
www.OnBarcode.com
Make Linear Barcode In .NET
Using Barcode printer for ASP.NET Control to generate, create 1D image in ASP.NET applications.
www.OnBarcode.com
For a typical web or enterprise application, transaction-scoped identity is preferred. Process-scoped identity offers potential advantages in terms of cache utilization and the programming model for reuse of instances across multiple transactions; but in a pervasively multithreaded application, the cost of always synchronizing shared access to persistent objects in the global identity map is too high. It s simpler, and more
Data Matrix 2d Barcode Decoder In None
Using Barcode recognizer for Software Control to read, scan read, scan image in Software applications.
www.OnBarcode.com
Barcode Maker In VS .NET
Using Barcode printer for Reporting Service Control to generate, create Barcode image in Reporting Service applications.
www.OnBarcode.com
Drawing Barcode In .NET
Using Barcode generation for .NET framework Control to generate, create Barcode image in .NET applications.
www.OnBarcode.com
Draw EAN / UCC - 13 In Java
Using Barcode creation for Java Control to generate, create GS1 128 image in Java applications.
www.OnBarcode.com
Decode Code-128 In VS .NET
Using Barcode scanner for VS .NET Control to read, scan read, scan image in .NET framework applications.
www.OnBarcode.com
UPC Symbol Maker In None
Using Barcode generation for Font Control to generate, create UPC-A Supplement 5 image in Font applications.
www.OnBarcode.com
Copyright © OnBarcode.com . All rights reserved.