Programming Entity Framework - Cdn.oreilly.com

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Creating a Common Wrapper to Handle Query Execution Exceptions 585 SaveChanges Command Execution Exceptions 587 Model and Mapping Constraints Are Broken: UpdateException 587 Exceptions Thrown by Broken Constraints in the Database 588 Automatically Rolling Back SaveChanges When an UpdateException Occurs 589 ObjectStateEntries Returned by Object Services Exceptions 589 General Entity Exceptions That May Occur When Executing Queries or Commands 590 InvalidOperationExceptions 590 Exceptions When Multiple Parties Edit Data Concurrently 591 Handling Concurrency Conflicts 591 Understanding Optimistic Concurrency Options in the Entity Framework 592 Ignoring Concurrency Conflicts 592 Forcing the User’s Data to the Server (ClientWins) 593 Refreshing the User’s Data with Server Data (StoreWins) 593 Determining the Scope of Changes 593 Using rowversion for Concurrency Checks 594 Implementing Optimistic Concurrency with the Entity Framework 595 Flagging a Property for Concurrency Checking 595 How the Entity Framework Uses the ConcurrencyMode Property 595 Concurrency Checking Without a rowversion Field 597 Concurrency Checking on a Checksum in the Data Store 597 Concurrency Checks for EntityReference Navigation Properties 598 Concurrency Checks and Inherited Types 598 Concurrency Checks and Stored Procedures 600 Handling OptimisticConcurrencyExceptions 602 Using ObjectContext.Refresh 602 Using ClientWins Refresh 603 Using StoreWins Refresh 605 Refreshing Collections of Entities 606 Refreshing Related Entities in a Graph 608 Rewinding and Starting Again, and Maybe Again After That 609 What If a Relationship, But No Scalar Properties, Changes? 611 Reporting an Exception 612 Handling Concurrency Exceptions at a Lower Level 613 Handling Granular Exceptions Without User Intervention 613 Handling Multiple Conflicts 616 Handling Exceptions When Transactions Are Your Own 617 Summary 619 Table of Contents | xvii
19. Using Your Own Custom Classes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 621 Mapping Classes to the Entity Data Model 621 Mapping Rules for Custom Classes and Their Properties 622 Inheriting from EntityObject 622 Metadata Attributes 623 Entity Classes 624 Scalar Properties 625 Navigation Properties 627 Mapping the Remaining Entities in the Model 631 Mapping the EntityContainer 631 Resolving Conflicts Between Custom Classes and Designer-Generated Classes 631 Querying Using the Custom Classes 631 Implementing the IPOCO Interfaces 632 The IEntityWithKey Interface 632 The IEntityWithChangeTracker Interface 633 The IEntityWithRelationships Interface 636 Working with the IPOCO-Enabled Objects 637 Custom Class Assemblies and Entity Data Model Files 638 Accessing the Model Files When They Are Not in a Referenced Assembly 639 Summary 639 20. Using the Entity Framework in n-Tier Client-Side Applications . . . . . . . . . . . . . . . . 641 Thinking in Layers 641 Organizing Your Layers 643 Finding Your Motivation: A Master/Detail Data Entry Form That Will Use the DataBridge Class 644 Preventing Non-UI Logic from Leaking into the UI 644 Implementing Logic That Fits Best in the Entity Partial Classes 646 Creating an IsDirty Property for the ObjectContext 647 Building the CommandExecutor Class 648 Building the DataBridge Class 652 Using a Long-Running ObjectContext 652 Implementing the Primary Elements of the DataBridge Class 653 Creating a Class for Lightweight Objects to Be Used in UI Pick Lists 654 Creating the Main Entity Pick List: For Customer Names 655 Using MergeOptions to Cache or Refresh a Pick List 656 Building a Frequently Used Entity Graph for the UI 656 Supplying Additional Lists for UI Drop-Downs 660 Saving Changes 662 Rolling Back User Changes 663 Using the DataBridge Class for Data Binding in a Master/Detail Form 666 xviii | Table of Contents
Page 1 and 2: Free Sampler
Page 3 and 4: Programming Entity Framework by Jul
Page 5 and 6: The EDM Within the Entity Framework
Page 7 and 8: Retrieving a Single Entity with Get
Page 9 and 10: Breaking Apart the ObjectQuery 222
Page 11 and 12: Using a New EntityDataSource to Add
Page 13 and 14: Insert, Update, and Delete Function
Page 15: Digging Through ObjectStateEntry 53
Page 19 and 20: Designing the Service Interface 725
Page 21 and 22: In addition to POCO support, the te
Page 23 and 24: using System.Text; namespace Chapte
Page 25 and 26: } } public ObjectSet Addresses { ge
Page 27 and 28: } If you run the code now, you will
Page 29 and 30: Using Proxies to Enable Change Noti
Page 31 and 32: Figure 13-2. A high-level view of t
Page 33 and 34: Rule 2: To enable lazy loading on a
Page 35 and 36: using System.Collections.ObjectMode
Page 37 and 38: Modifying the POCO Template Althoug
Page 39 and 40: The next step is to modify the temp
Page 41 and 42: get; set; } public string Street1 {
Page 43: Want to read more? You can find thi

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