update primary key value using entity framework

... the primary key in the table in the database, the UpdateCommand of the DataAdapter needs to locate the row based on the original primary key and update the primary key value with the current value ... Recipe 4.8 Updating a Primary Key Value Problem You changed a primary key value in a DataTable and updated the change back to the underlying data source, but the value in the data source ... unchanged. You need to update a primary key value in the data source underlying the DataTable. Solution Use the SourceVersion property of SqlParameter to update the primary key value in the data...

Ngày tải lên: 26/01/2014, 10:20

Ngày tải lên: 11/08/2014, 05:22

Ngày tải lên: 20/10/2014, 14:10

Ngày tải lên: 20/10/2014, 14:21

... Step by Step Running Framework Queries The Entity Framework provides four key methods for querying data exposed by the entity model.  Write SQL-like queries using the Entity SQL language. ... home for each piece of data. Mapping files use an .msl file extension. Using the Entity Framework Using a model in the Entity Framework requires four essential steps: 1. Build the model. 2. Generate ... the Entity Framework After completing this chapter, you will be able to:  Understand the high-level concepts of the ADO.NET Entity Framework  Distinguish between the three main Entity Framework...

Ngày tải lên: 03/10/2013, 00:20

... choose which candidate key will be the primary key at this point, but one could do so. When there is only one candidate key, we will generally speak of it as the primary key, simply because it ... will be the primary key. 8. Once again, embellish the building entity to include names (and only the names) of the janitorial staff. 9. Add a multi-valued attribute to the building entity. 10. ... the primary key is a candidate key. In Figure 2.6 we have also depicted the short form of the ER diagram (at the bottom) with composite attributes and multi-valued attributes as well as primary...

Ngày tải lên: 22/10/2013, 10:15

... Dynamic Data với ADO.NET Entity Framework 11 using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.DynamicData; using System.ComponentModel.DataAnnotations; ... | Bài số 8: Dynamic Data với ADO.NET Entity Framework 6 1.3. Tạo Data Model với ADO.NET Entity Framework Trong ví dụ này chúng ta dùng ADO.NET Entity Framework để truy cập vào CSDL My_Database.mdf. ... Dynamic Data với ADO.NET Entity Framework 2 Bài số 8 DYNAMIC DATA VỚI ADO.NET Entity Framework Bài này giới thiệu cách xây dựng ứng dụng Dynamic Data với ADO.NET Entity Framework. 1. Xây...

Ngày tải lên: 13/12/2013, 09:15

... automatically incremented, called an identity field. This identity field can also be set as the primary key field, again so that the record is made unique. The primary key field will also be indexed. ... Security Number, and make that into a primary key field. By making a field the primary key field, you will need to make that field unique and prohibit null values there. The alternative to a current ... menu. 2.3 Define a Primary Key and Other Indexes Indexes are used to improve performance when querying data, such as searching on fields and sorting information. The primary key is an index that...

Ngày tải lên: 14/12/2013, 20:16

... The Cascade Update Related Fields check box indicates whether a change to a value in the primary key column of the primary key table (the parent table) is also made to the foreign key column ... to change the primary key column value and apply the same change to the child rows? The easiest way is to simply delete the rows in the child table first, change the primary key value in the ... table. Updating the Primary Key of a Parent Table and Pushing the Change to the Database In this section you'll learn what happens if you attempt to update the primary key in a parent table...

Ngày tải lên: 24/12/2013, 01:17

... check if a column value contains a null value using methods such as I sContactNameNull(), and you can set a column to null using methods such as Reading a Column Value Using Strongly Typed ... </xs:choice> </xs:complexType> <xs:unique name="MyDataSetKey1" msdata:PrimaryKey="true"> <xs:selector xpath=".//mstns:Customers" /> ... Using Strongly Typed DataSet Classes A strongly typed DataSet object allows you read a column value using a property with the same name as the column. For example, to read the CustomerID of a...

Ngày tải lên: 21/01/2014, 07:20

... made to the row have been rolled back. The DefaultValue of the GUID primary key column in both parent and child tables is set to a new GUID using the NewGuid( ) method of the Guid structure ... when the tables are defined. This causes a new GUID value to be assigned to the primary key when the first row is added. Because the DefaultValue for the column is calculated once when the property ... parentTable.Columns; col = cols.Add(PARENTID_FIELD, typeof(Guid)); col.DefaultValue = Guid.NewGuid( ); parentTable.PrimaryKey = new DataColumn[] {col}; cols.Add(FIELD1_FIELD, typeof(String)).MaxLength...

Ngày tải lên: 21/01/2014, 11:20

... Property to an Entity 543 Setting a Foreign Key Property 544 Setting an EntityReference Using an EntityKey 544 Loading, Adding, and Attaching Navigation Properties 545 Lazy Loading 545 EntityReference.Load ... 1: Introducing the ADO.NET Entity Framework www.it-ebooks.info Accessing Foreign Keys When There Is No Foreign Key Property 308 Working with Related EntityReference Data 309 Using EntityDataSource.Include ... attention from Microsoft. When working with the Entity Framework, you will implement an EDM that is par- ticular to the Entity Framework. In the Entity Framework, an EDM is represented by a single...

Ngày tải lên: 08/03/2014, 18:20

... Composite Keys Entity Framework supports entities that have composite keys, that is, entities where the key is made up of two or more properties. For example, you may have a Passport entity that ... PassportNumber as its key. To locate entities with a composite key you supply each of the key values to Find: context.Passports.Find("USA", "123456789") The key values must be supplied ... What’s Coming Next for Entity Framework . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235 Understanding Entity Framework s Version Numbers 235 Entity Framework 5.0 236 Enums...

Ngày tải lên: 08/03/2014, 18:20

... with Related EntityReference Data 309 Using EntityDataSource.Include to Get Related Data 309 Displaying Data That Comes from EntityReference Navigation Properties 310 Using a New EntityDataSource ... the Entity Framework. Therefore, ODBC is not a valid provider for the Entity Framework. Unless someone creates a provider specifically for Access, you won’t be able to use it with Entity Framework ... EntityCollections 117 Using Entity SQL SET Operators 117 Aggregating with Query Builder Methods 118 Using Joins 118 Nesting Queries 119 Grouping in Entity SQL 120 Returning Entities from an Entity...

Ngày tải lên: 15/03/2014, 20:20

... that included Code First. The core Entity Framework API, System.Data .Entity. dll, is still part of the .NET Framework and was untouched by Entity Framework 4.1 and 4.2. The Entity Framework 4.1 release also ... only way Entity Framework was able to manage in-memory objects was by requiring classes to inherit from Entity Framework s EntityObject. The EntityObject communicates its changes to Entity Framework, ... referred to as Entity Framework 4.1, in April 2011. The version number will increment as subsequent updates are released. Entity Framework 4.2 was released in October 2011 and replaces Entity Framework...

Ngày tải lên: 23/03/2014, 02:20

... What’s Coming Next for Entity Framework . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235 Understanding Entity Framework s Version Numbers 235 Entity Framework 5.0 236 Enums ... tasks using the Entity Framework. The focus of this chapter will be on retrieving data from the database. One of the great benefits of using an Object Relational Mapper (ORM), such as Entity Framework, ... ADO.NET Entity Framework, has had two major releases as part of the .NET Framework. .NET 3.5 brought us the first version of Entity Framework, which is covered in the first edition of Programming Entity Framework...

Ngày tải lên: 23/03/2014, 02:20

... APPLIED ENTITY FRAMEWORK 355 14 ■ Designing the application around Entity Framework 357 15 ■ Entity Framework and ASP.NET 378 16 ■ Entity Framework and n-tier development 396 17 ■ Entity Framework ... Letting Entity Framework ease your life 23 What is O/RM? 23 ■ The benefits of using Entity Framework 24  When isn’t O/RM needed? 26 1.6 How Entity Framework performs data access 26 The Entity ... with stored procedures 275 Using stored procedures to persist an entity 276 ■ Using stored procedures to update an entity with concurrency 279 ■ Persisting an entity that’s in an inheritance...

Ngày tải lên: 05/05/2014, 11:21

... vii Contents Introduction xvii PART I INTRODUCING THE ENTITY FRAMEWORK Chapter 1 Getting to know the Entity Framework 3 Dening an entity 4 Understanding the Entity Framework elements 6 Considering the conceptual ... .11 Developing a simple Entity Framework example 12 Starting the Entity Data Model Wizard 12 Using the Entity Data Model Designer 16 Working with the mapping details 18 Using the resulting framework to ... coding—that’s a tall order! The Entity Framework fullls this promise and far more. Each version of the Entity Framework is more capable than the last. The latest version, Entity Framework version 5, provides...

Ngày tải lên: 05/05/2014, 15:11

Ngày tải lên: 23/05/2014, 15:23