entity-framework-6

问题 I am using EF6 for storing instances of the report class in my database. The database already contains data. Say I wanted to add a property to report , public class report { // ... some previous properties // ... new property: public string newProperty{ get; set; } } Now if I go to the package-manager console and execute add-migration Report-added-newProperty update-database I will get a file in the '/Migrations' folder adding a newProperty column to the table. This works fine. However, on

问题 I am using EF6 for storing instances of the report class in my database. The database already contains data. Say I wanted to add a property to report , public class report { // ... some previous properties // ... new property: public string newProperty{ get; set; } } Now if I go to the package-manager console and execute add-migration Report-added-newProperty update-database I will get a file in the '/Migrations' folder adding a newProperty column to the table. This works fine. However, on

问题 In my project I have: public class BaseEntity { [Key] public int Id {get; set; } } Then I have to define 10+ POCO classes to define the tables in my database: public class MyTable : BaseEntity { //define properties here } Of course, because MyTable inherits from BaseEntity I get that Discriminator field. I want to get rid of the Discriminator field as I do not need the table BaseEntity to be created nor I need to implement some sort of inheritance into my database. Is it possible? 回答1: A

问题 In my project I have: public class BaseEntity { [Key] public int Id {get; set; } } Then I have to define 10+ POCO classes to define the tables in my database: public class MyTable : BaseEntity { //define properties here } Of course, because MyTable inherits from BaseEntity I get that Discriminator field. I want to get rid of the Discriminator field as I do not need the table BaseEntity to be created nor I need to implement some sort of inheritance into my database. Is it possible? 回答1: A

问题 TL;DR; What is the best way to standardize and abstract IQueryable construction in large data access layers? Are extensions acceptable or encouraged? Background We're using Entity Framework 6 with a Repository pattern as our Data Access Layer. In order to make our data calls more efficient, we've recently started using some structured Data Transfer Objects to force ourselves to only pull from the database what is necessary. For example: We have a dashboard that uses 15 of 500 properties of an

问题 I am using EntityFramework as my Data Access Layer in a Visual Studio C# project. I have added a new entity model and built right away without adding or doing anything to test its functionality. Unfortunately, the build failed with many errors like: CS0426 The type name 'Data' does not exist in the type 'System' CS0138 A 'using namespace' directive can only be applied to namespaces; 'System' is a type not a namespace. Consider a 'using static' directive instead CS0246 The type or namespace

问题 I am using EntityFramework as my Data Access Layer in a Visual Studio C# project. I have added a new entity model and built right away without adding or doing anything to test its functionality. Unfortunately, the build failed with many errors like: CS0426 The type name 'Data' does not exist in the type 'System' CS0138 A 'using namespace' directive can only be applied to namespaces; 'System' is a type not a namespace. Consider a 'using static' directive instead CS0246 The type or namespace

问题 I am using EntityFramework 6 and I used Update Model from Database after inserting table in the database, I got above error.Please state how to overcome this problem. 回答1: Open the edmx file on notepad, find the unmapping association and remove it. It should work. 回答2: I got the same error and found that the foreign key in the table I had added was not of the same type as in the referenced table. 回答3: Not too satisfying, but I solved it by removing and re-adding the model: Right-click on edmx

问题 In my project we have a branch model that has a separate development branch and has a separate branch for each release. It may look like this: dev ______ ______ / \ / \ master --+---+----+---+---+----+----+--- (...) r1 \______/ r2 \_______/ So we develop on dev merge it to master and then we create a release branch (r1, r2, ...). We want to use EF 6 (manual not automatic) migrations but we have a question that we don't know how to answer. Imagine this: dev _(1)__ ____(4) / \ / \ master --+---

问题 In my project we have a branch model that has a separate development branch and has a separate branch for each release. It may look like this: dev ______ ______ / \ / \ master --+---+----+---+---+----+----+--- (...) r1 \______/ r2 \_______/ So we develop on dev merge it to master and then we create a release branch (r1, r2, ...). We want to use EF 6 (manual not automatic) migrations but we have a question that we don't know how to answer. Imagine this: dev _(1)__ ____(4) / \ / \ master --+---