entity-framework

问题 I'm trying to get Entity Framework (6.4.4. the newest version in summer 2020) working together with SQLite (1.0.113.1, also latest in summer 2020). I found a lot of information about how to do this, but this information was not always helpful, quite often they contradicted each other. Now that I found out how to do it, I decided to jot down how I did it. The question describes the classes and the tables, the answer will describe how to do it. I describe a database for Schools, where every

问题 I'm using EF5 Code First in MVC4. There are tables where fields have decimal datatypes. I just wanted to update the precision of decimal originally from (18,2) to (18,4) . Please help. To achieve the goal I just modified the OnModelCreating something like this: protected override void OnModelCreating(DbModelBuilder modelBuilder) { modelBuilder.Entity<DealerLevelDiscount>().Property(d =>d.Discount ).HasPrecision(18, 4); modelBuilder.Entity<DealerTransaction>().Property(d => d.ProductDiscount)

问题 I have a simple TPT Inheritance, EF 6.1.1 public class Base { public int Id {get; set;} } public class Derived : Base { public int SomeProperty {get; set;} } Note that in my case Base is NOT an abstract class, because in my domain can exists an instance of Base without Derived . DbContext : public class ApplicationDbContext : DbContext { protected override void OnModelCreating(DbModelBuilder modelBuilder) { base.OnModelCreating(modelBuilder); modelBuilder.Entity<Derived >().ToTable("Derived")

问题 I have a simple TPT Inheritance, EF 6.1.1 public class Base { public int Id {get; set;} } public class Derived : Base { public int SomeProperty {get; set;} } Note that in my case Base is NOT an abstract class, because in my domain can exists an instance of Base without Derived . DbContext : public class ApplicationDbContext : DbContext { protected override void OnModelCreating(DbModelBuilder modelBuilder) { base.OnModelCreating(modelBuilder); modelBuilder.Entity<Derived >().ToTable("Derived")

问题 I am creating a schema where the following logic applies: A String can belong to multiple locations. Multiple Locations can have multiple String , or no String . The DateTime (As DateScraped ) at which the relationship between Location and String was formed must be recorded. Basically, I've mapped the relationship as a many-to-many relationship using a junction table like so: In mapping the chart in Code First EF6 (Using SQLite), I have the following objects: public class Location { [Key,

问题 I am creating a schema where the following logic applies: A String can belong to multiple locations. Multiple Locations can have multiple String , or no String . The DateTime (As DateScraped ) at which the relationship between Location and String was formed must be recorded. Basically, I've mapped the relationship as a many-to-many relationship using a junction table like so: In mapping the chart in Code First EF6 (Using SQLite), I have the following objects: public class Location { [Key,

问题 I am creating a schema where the following logic applies: A String can belong to multiple locations. Multiple Locations can have multiple String , or no String . The DateTime (As DateScraped ) at which the relationship between Location and String was formed must be recorded. Basically, I've mapped the relationship as a many-to-many relationship using a junction table like so: In mapping the chart in Code First EF6 (Using SQLite), I have the following objects: public class Location { [Key,

问题 I have these tables: Category CategoryId CategoryTitle ... ICollection<Article> Articles Each category can have several articles: Article ArticleId ArticleTitle NumberOfComment NumberOfView ... ICollection<ArticleReview> Reviews And each article has several reviews by some user: ArticleReview ArticleReviewId ReviewPoint ArticleId ReviewerId i am trying to export excel report using EPPlus package Here is my ExcelExport class : public class excelExport { public string ArticleTitle { get; set; }

问题 What is the equal code in EntityFramework to this sql code? select Scope_Identity() I want to get the id of the last record that i have inserted to database in EF. 回答1: You must ensure that your key property is mapped with StoreGeneratedPattern.Identity (here you can find some more about this setting). This should be used as default when generating the model from MS SQL database where the key column is defined with IDENTITY . After that it is enough to call SaveChanges on the context and the

问题 I have implemented EntityFramework pattern along with Repository and Unit Of Work. The implementation is similar to Code Project Repository Example, however I need an enhancement for the Unit Of Work. The unit of work public class GenericUnitOfWork : IDisposable { // Initialization code public Dictionary<Type, object> repositories = new Dictionary<Type, object>(); public IRepository<T> Repository<T>() where T : class { if (repositories.Keys.Contains(typeof(T)) == true) { return repositories