مشخصات کتاب

نویسنده:

Julia Lerman and Rowan Miller
تاریخ انتشار:

2012
زبان:

انگلیسی
تعداد بازدید:

27384
تعداد دانلود:

849
لایک ها :

0

Programming Entity Framework- DbContext

نویسنده :Julia Lerman and Rowan Miller

1. Introducing the DbContext API . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Getting the DbContext API into Your Project 2

Looking at Some Highlights of the DbContext API 3

Reducing and Simplifying Ways to Work with a Set 5

Retrieving an Entity Using ID with DbSet.Find 5

Avoiding Trolling Around the Guts of Entity Framework 6

Working with the BreakAway Model 6

Getting the Sample Solution 6

Getting DbContext from an EDMX Model 8

Ensuring DbContext Instances Get Disposed 11

2. Querying with DbContext . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Writing Queries with LINQ to Entities 13

Querying All the Data from a Set 16

Using LINQ for Sorting, Filtering, and More 18

Finding a Single Object 21

Querying Local Data 24

Using the Load Method to Bring Data into Memory 26

Running LINQ Queries Against Local 27

Working with the ObservableCollection Returned by Local 29

Loading Related Data 30

Lazy Loading 31

Eager Loading 33

Explicit Loading 36

Checking If a Navigation Property Has Been Loaded 38

Querying Contents of a Collection Navigation Property 39

Explicit Loading a Subset of the Contents of a Navigation Property 41

3. Adding, Changing, and Deleting Entities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

Working with Single Entities 44

Adding New Entities 44

Changing Existing Entities 45

Deleting Existing Entities 46

Multiple Changes at Once 51

The “Find or Add” Pattern 52

Working with Relationships 53

Adding a Relationship Between Objects 54

Changing a Relationship Between Objects 56

Removing a Relationship Between Objects 57

Working with Change Tracking 59

Using Snapshot Change Tracking 60

Understanding When Automatic Change Detection Occurs 60

Controlling When DetectChanges Is Called 60

Using DetectChanges to Trigger Relationship Fix-up 63

Enabling and Working with Change Tracking Proxies 64

Ensuring the New Instances Get Proxies 67

Creating Proxy Instances for Derived Types 68

Fetching Entities Without Change Tracking 69

4. Working with Disconnected Entities Including N-Tier Applications . . . . . . . . . . . . . 71

A Simple Operation on a Disconnected Graph 72

Exploring the Challenges of N-Tier 74

Using Existing N-Tier Frameworks That Support Graph Modification 76

Using Explicit Operations on the Server Side 77

Replaying Changes on the Server 77

Understanding How DbContext Responds to Setting the State of a Single

Entity 78

Marking a New Entity as Added 79

Marking an Existing Entity as Unchanged 80

Marking an Existing Entity as Modified 81

Registering an Existing Entity for Deletion 83

Working with Relationships with and Without Foreign Keys 85

Setting the State for Multiple Entities in an Entity Graph 88

Getting the Graph into the Context 88

Setting the State of Entities in a Graph 90

Building a Generic Approach to Track State Locally 92

Creating a Generic Method That Can Apply State Through Any Graph 96

Concurrency Implications 98

Tracking Individually Modified Properties 99

Recording Modified Property Names 99

Recording Original Values 102

5. Change Tracker API . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111

Change Tracking Information and Operations for a Single Entity 111

Working with the State Property 112

Working with Current, Original, and Database Values 113

Working with DbPropertyValues for Complex Types 119

Copying the Values from DbPropertyValues into an Entity 122

Changing Values in a DbPropertyValues 123

Working with Individual Properties 128

Working with Scalar Properties 128

Working with Complex Properties 131

Working with Navigation Properties 133

Refreshing an Entity from the Database 137

Change Tracking Information and Operations for Multiple Entities 139

Using the Change Tracker API in Application Scenarios 141

Resolving Concurrency Conflicts 141

Logging During Save Changes 147

6. Validating with the Validation API . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153

Defining and Triggering Validation: An Overview 154

Validating a Single Object on Demand with GetValidationResult 155

Specifying Property Rules with ValidationAttribute Data Annotations 157

Validating Facets Configured with the Fluent API 158

Validating Unmapped or “Transient” Properties 158

Validating Complex Types 159

Using Data Annotations with an EDMX Model 159

Inspecting Validation Result Details 160

Inspecting Individual Validation Errors 161

Exploring More ValidationAttributes 163

Using CustomValidationAttributes 164

Validating Individual Properties on Demand 166

Specifying Type-Level Validation Rules 166

Using IValidatableObject for Type Validation 167

Validating Multiple Rules in IValidatableObject 169

Using CustomValidationAttributes for Type Validation 171

Understanding How EF Combines Validations 173

Validating Multiple Objects 175

Validating When Saving Changes 178

Reviewing ObjectContext. SaveChanges Workflow 179

Understanding DbContext.SaveChanges Workflow 179

Disabling Validate Before Save 182

7. Customizing Validations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183

Overriding ValidateEntity in the DbContext 183

Considering Different Ways to Leverage ValidateEntity 187

Updating Data During SaveChanges 192

Overriding SaveChanges When Validation Occurs 193

Comparing ValidateEntity to SaveChanges for Custom Logic 197

Using the IDictionary Parameter of ValidateEntity 198

Controlling Which Entities Are Validated in ValidateEntity 200

8. Using DbContext in Advanced Scenarios . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203

Moving Between ObjectContext and DbContext 203

Accessing ObjectContext Features from a DbContext 204

Adding DbContext into Existing .NET 4 Applications 205

Leveraging SQL Server Operators Exposed in SqlFunctions 208

Querying Derived Types with DbSet 209

Understanding the Interface Property Limitation 210

Considering Automated Testing with DbContext 210

Testing with DbSet 211

Exploring a Scenario That Unnecessarily Queries the Database 212

Reducing Database Hits in Testing with IDbSet 214

Creating an IDbSet Implementation 214

Abstracting BreakAwayContext for Tests 217

Reviewing the Implementation 221

Supplying Data to a FakeDbSet 221

Accessing the Database Directly from DbContext 222

Executing Queries with Database.SqlQuery and DbSet.SqlQuery 223

Tracking Results of SqlQuery 226

Executing Commands from the Database Class 226

Providing Multiple Targeted Contexts in Your Application 227

Reusing Classes, Configurations, and Validation Across Multiple

Contexts 227

Ensuring That All DbContexts Use a Single Database 231

Validating Relationship Constraints and Other Validations with Multiple

Contexts 232

Getting Code First to Create Full BreakAwayContext Database 232

9. What’s Coming Next for Entity Framework . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235

Understanding Entity Framework’s Version Numbers 235

Entity Framework 5.0 236

Enums 236

Spatial Data 236

Performance Improvements 236

Multiple Result Sets from Stored Procedures 237

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مشخصات کتاب

Julia Lerman and Rowan Miller

2012

انگلیسی

27384

849

0

Programming Entity Framework- DbContext

آموزش Programming Entity Framework : Entity Framework

آموزش Entity Framework 4 in Action : Entity Framework

آموزش Entity Framework 6 Recipes : Entity Framework