If you don't specify a connection string or the name of one explicitly, Entity Framework assumes that the connection string name is the same as the class name. It isn'tnecessary to call the SaveChanges method after each group of entities, as is done here, but doing that helpsyou locate the source of a problem if an exception occurs while the code is writing to the database
Code First Approach in Entity Framework using Data Annotation and Fluent API - CodeProject
Now, in previous days, developers used to write code manually to fetch data and convert the data to domain object and then pass the object across layers. Code First Approach As the name suggests, in this approach, we will write code at first to generate database and in one good day, we will run those codes to see database in DB server
Introduction to Entity Framework Code First
The name of the database created will be BlogDb (as specified in data context constructor) and two tables - BlogPosts and Categories - will also be created. After the fourth play was whistled dead, Harris was lying on top of Lutui and delivered a closed-fist punch through Lutui's facemask a few yards away from the Cardinals bench
The term "Independent Association" resonates for us because they are independently mapped, whereas FK Associations need no mapping, simply mapping the Entity(Set) is sufficient. The existing style Independent Associations will still be possible, but we expect that FK Associations will become most peoples automatic choice because they simplify so many common Entity Framework coding tasks
Relationship in Entity Framework Using Code First Approach With Fluent API - CodeProject
Navigation properties allow you to navigate and manage relationships in both directions, returning either a reference object (if the multiplicity is either one or zero-or-one) or a collection (if the multiplicity is many). Finally what you put up as a unit test is not a unit test, it's basically a console app with test attributes you may want to address this by adding unit tests that great rather then just add values to a database
As an alternative you might want to consider adding a IsDefaultSurvey field on the Survey object so that you can query for the default survey through the Surveys collection that you have on the Client object
The problem of this association type was the internal implementation in Entity framework which makes it sometimes (especially in detached scenarios) very hard to use. When using Independent association we can't map a foreign key to a property - Visual Studio will throw a validation error in EDMX file if we try to do it
That said, EF team has this feature on their list for the future, so hopefully it will be supported in a later release of EF and until then the workaround that I showed here is going to be the way to implement one-to-one foreign key associations in EF Code First. However, Code First will not recognize them as the foreign keys for the associations since their names are not aligned with the conventions that it has to infer foreign keys
As you can tell from the type of the inner exception (SqlException), it has nothing to do with EF or Code First; it has been generated purely by SQL Server when Code First was trying to create a database based on our object model. Create a Unique Constraint To Enforce the Relationship as a One to OneWe can manually create unique constraints on the foreign keys in the database after Code First creates it for us but if you are like me and prefer to create your database in one shot then there is a way to have Code First create the constraints as part of its database creation process
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