Transactions and Conne ction Management in Visual C#.NET

Creation QR Code 2d barcode in Visual C#.NET Transactions and Conne ction Management
Transactions and Conne ction Management
Generate QR Code ISO/IEC18004 In Visual C#.NET
Using Barcode maker for Visual Studio .NET Control to generate, create Denso QR Bar Code image in Visual Studio .NET applications.
In summary, LINQ to SQL provides a rich set of tools to handle simultaneous changes You can specify what properties should be used to detect con icts, choose to end on rst con ict, or get information about all con icts and resolve con icts with simple built-in options You can also refresh the state for unmodi ed objects These tools cover concurrent changes between the time that objects are read and the time that the changes are submitted But an equally important issue is to ensure that all the changes are done atomically as one unit of work or are not done at all This is accomplished using transactions, which are covered next
Bar Code Generator In Visual C#
Using Barcode encoder for .NET framework Control to generate, create bar code image in .NET applications.
Transactions and Connection Management
Quick Response Code Creation In .NET
Using Barcode generation for ASP.NET Control to generate, create Denso QR Bar Code image in ASP.NET applications.
LINQ to SQL lets you retrieve a graph of objects for modi cation All changes to the graph can then be submitted as a single unit of work with a call A unit of work may include multiple updates, inserts, and deletes Each operation on an entity is handled as a single database command So the set of changes requires a set of commands This raises some obvious questions: What happens when one of the commands fails say, due to a change con ict or some other failure What happens if someone else makes changes between two commands in a set of changes LINQ to SQL addresses these issues by executing the set of SQL commands as a single transaction Here is the conceptual multistep process for call: a 1 Compute the change set for the entities in the The result is a list of entities to be updated, a list of entities to be inserted, and a list of entities to be deleted
Drawing QR-Code In Visual Studio .NET
Using Barcode maker for .NET framework Control to generate, create QR-Code image in .NET framework applications.
9: Modifying Obje cts with LINQ to SQL
QR Code 2d Barcode Creation In VB.NET
Using Barcode encoder for Visual Studio .NET Control to generate, create QR Code image in Visual Studio .NET applications.
2 Order the changes based on foreign key dependencies For example, must be inserted before an can be inserted, an because the latter requires the key value of the former 3 Open a connection to the database, and start a transaction or use the ambient transaction , , and 4 Execute ate checks for con ict detection SQL commands, with appropri-
Barcode Creation In Visual C#
Using Barcode generation for .NET framework Control to generate, create barcode image in Visual Studio .NET applications.
5 Run queries for database-generated values 6 If all commands execute successfully, commit the transaction to make the changes persistent in the database Otherwise, roll back the transaction and throw exception to inform the caller that failed The transaction around all the SQL commands addresses these questions It ensures that either all the changes are persisted or all of them are ignored, leaving the database in the same state as before the beginning of the transaction Second, depending on the transaction s isolation level, the database server prevents con icting changes between the commands LINQ to SQL starts a transaction by default to minimize the chance of an error You do not have to remember to start a transaction for every call However, you still have control over the transaction boundary if you so desire You have two additional options at your disposal for more advanced scenarios In most common cases, you do not need the following options; you can just rely on the implicit transaction started call by a to perform additional operations in the context Use a of the transaction LINQ to SQL detects an ambient transaction and uses it The transaction is committed or aborted based on the for model Failures other than also usual get to veto the transaction s completion yourself, and use it to execute other commands Create a as necessary Then tell LINQ to SQL to use it by setting the property You still get to start and commit or roll back the transaction as you want
Bar Code Creation In Visual C#.NET
Using Barcode creation for Visual Studio .NET Control to generate, create bar code image in VS .NET applications.
Transactions and Conne ction Management
Code39 Generation In C#.NET
Using Barcode generation for VS .NET Control to generate, create USS Code 39 image in Visual Studio .NET applications.
Use of is convenient when you want to perform additional operations A common scenario for such a broader scope is to in one transaction, as shown in the include queries and following code This provides a pessimistic concurrency control option, where you want to avoid con icts rather than detecting and resolving them Another usage scenario is to enable access to multiple transactional sources using a promotable or distributed transaction
Code 128 Code Set B Creation In Visual C#.NET
Using Barcode generator for .NET framework Control to generate, create Code 128 image in .NET framework applications.
Use of allows interoperability with code using ADO NET relational APIs, as shown in the following code It lets you mix direct SQL commands and LINQ to SQL operations, and it also allows you to change the isolation level on the transaction if you want
Generating ECC200 In Visual C#.NET
Using Barcode generation for VS .NET Control to generate, create ECC200 image in .NET framework applications.
Optimistic concurrency checks and transactions provide complementary support The former allows disconnected operation No resources are held on the database server while working with entities retrieved in
Encoding Barcode In .NET
Using Barcode generation for ASP.NET Control to generate, create barcode image in ASP.NET applications.
ANSI/AIM Code 128 Scanner In Visual Studio .NET
Using Barcode decoder for VS .NET Control to read, scan read, scan image in VS .NET applications.
Barcode Printer In Java
Using Barcode encoder for Java Control to generate, create bar code image in Java applications.
Paint Bar Code In VS .NET
Using Barcode creator for VS .NET Control to generate, create barcode image in VS .NET applications.
GS1 128 Generator In VS .NET
Using Barcode creator for ASP.NET Control to generate, create EAN128 image in ASP.NET applications.
USS-128 Printer In .NET
Using Barcode printer for VS .NET Control to generate, create UCC-128 image in .NET applications.