Viastudy ef core_cheat_sheet
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This document provides an overview of Entity Framework Core, including supported platforms, common operations using the DbContext object, conventions for mapping entities to database tables, and configuration options using the fluent API. It also lists features that are supported in EF Core and those that are not yet supported or planned.
Viastudy ef core_cheat_sheet
- 1. Entity Framework Core Cheat Sheet 1 Viastudy.com Platforms .NET Framework (Console, Winform, WPF, ASP.NET) .NET Core (Console, ASP.NET Core) Mono & Xamarin (in-progress) UWP (in-progress) EF Core - Working with DbContext Create and use DbContext object using (var context = new SchoolContext()) { //work with context here } Create Operation context.Add<Student>(newStudentObj); context.SaveChanges() //or context.Students.Add(newStudentObj); context.SaveChanges(); // or context.Entry(newStudentObj).State = EntityState.Added; context.SaveChanges(); Update Operation context.Update<Student>(StudentObj); context.SaveChanges(); //or context.Entry(studentObj).State = EntityState.Modified; context.SaveChanges(); Delete Operation Context.Remove(studentObj); context.SaveChanges(); //or context.Entry(studentObj).State = EntityState.Deleted; context.SaveChanges(); Get the current State of an entity varstate = context.Entry<Student>(studentObj).State; Execute raw SQL query for entity types varsList = context.Students.FromSql($"Select * from Student where StudentName=’name’").ToList<Student>(); Execute raw SQL commands int noOfRowsAffected = context.Database.ExecuteSqlCommand("CUD command"); Explicitly load navigation /reference entity context.Entry(student).Reference(s => s.Grade).Load(); Explicitly Load Collection context.Entry(student).Collection(s=>s.Courses).Load(); Find by PrimaryKey var student = context.Students.Find(1); Disable automatic detect changes context.ChangeTracker.AutoDetectChangesEnabled = false Disable Query Tracking context.ChangeTracker.QueryTrackingBehavior = QueryTrackingBehavior.NoTracking; Disable Automatic Detect Changes context.ChangeTracker.AutoDetectChangesEnabled = false; Eager Loading context.Students.Where(s => s.FirstName == "Bill") .Include(s => s.Grade).FirstOrDefault(); Multi Level Eager Loading context.Students.Where(s => s.FirstName == "Bill") .Include(s => s.Grade) .ThenInclude(g => g.Teachers); EF Core Conventions Schema dbo Table Name Same as DbSet<TEntity> property name in the context class. Primary key Name 1) Id 2) <Entity Class Name> Id (case insensitive) e.g. Id or StudentId property becomes primary key of Student by default. Foreign key property Name EF Core API will create a foreign key column for each reference navigation property in an entity with one of the following naming patterns. 1. <Reference Navigation Property Name>Id 2. <Reference Navigation Property Name><Principal Primary Key Property Name> Null column All reference type properties and nullable primitive properties. NotNull Column PrimaryKey properties and non-nullable primitive properties (int, decimal, datetime, float etc.) Index Clustered index on PrimaryKey columns. Non-clustered index on Foreignkey columns. Properties mapping to DB By default all properties will map to database. Cascade delete Enabled by default. EF Core Fluent API - Entity Type Configurations ToTable() - Maps an entity to database table modelBuilder.Entity<Student>().ToTable("StudentInfo"); modelBuilder.Entity<Student>() .ToTable("StudentInfo", "dbo"); ToTable() – Maps two entities to one database table modelBuilder.Entity<Student>().ToTable("Student"); modelBuilder.Entity<StudentDeail>() .ToTable("Student"); HasKey() - Configures Primary Key(s) modelBuilder.Entity<Student>().HasKey(s => s.StudId); HasAlternateKey() - Configures an alternate key in the EF model modelBuilder.Entity<Student>().HasAlternateKey(s=>s.Id)
- 2. Entity Framework Core Cheat Sheet 2 Viastudy.com HasIndex() - Configures an index on the specified properties modelBuilder.Entity<Student>().HasIndex(s => s.Id) HasOne() - Configures the One part of the relationship modelBuilder.Entity<Student>().HasOne(s => s.Grade) HasMany() - Configures the Many part of the relationship modelBuilder.Entity<Student>().HasMany(s => s.Courses) OwnsOne() - Configures a relationship where the target entity is owned by this entity modelBuilder.Entity<Student>() .OwnsOne(p => p.HomeAddress) .OwnsOne(p => p.PermanentAddress); EF Core Fluent API – Property Configuration HasColumnType - Configures a column data type modelBuilder.Entity<Student>() .Property(s => s.StudentName) .HasColumnType("varchar"); HasColumnName - Configures a Column name modelBuilder.Entity<Student>() .Property(s => s.StudentName) .HasColumnName("Name"); HasDefaultValue - Configures a default value modelBuilder.Entity<Student>() .Property(s => s.PendingFees) .HasDefaultValue(100); HasComputedColumnSql - Configures a computed column modelBuilder.Entity<Student>() .Property(s => s.PendingFees) .HasComputedColumnSql(“Sql here”); IsRequired - Configures a Null column modelBuilder.Entity<Student>().Property(s => s.DoB).IsRequired(false); IsRequired - Configures a NotNull column modelBuilder.Entity<Student>() .Property(s => s.DoB) .IsRequired(); HasMaxLength - Configures maximum Length for string column modelBuilder.Entity<Student>() .Property(s => s.StudentName) .HasMaxLength(50); IsUnicode - Configures a Unicode string column modelBuilder.Entity<Student>() .Property(s => s.StudentName) .IsUnicode(); //or modelBuilder.Entity<Student>() .Property(s => s.StudentName) .IsUnicode(false); IsConcurrencyToken – Configures a concurrency property modelBuilder.Entity<Student>() .Property(p => p.StudentName) .IsConcurrencyToken(); //or modelBuilder.Entity<Student>() .Property(p => p.RowVersion) .IsRowVersion(); HasField - Configures a backing field modelBuilder.Entity<Student>() .Property(s => s.StudentName) .HasField("_StudentName"); EF Core Fluent API – Relationship Configurations One-to-zero-or-one modelBuilder.Entity<Student>() .HasOne<StudentAddress>(s => s.Address) .WithOne(ad => ad.Student) One-to-Many modelBuilder.Entity<Student>() .HasOne<Grade>(s => s.Grade) .WithMany(g => g.Students) Many-to-Many modelBuilder.Entity<StudentCourse>() .HasKey(sc => new { sc.StudentId, sc.CourseId }); modelBuilder.Entity<StudentCourse>() .HasOne<Student>(sc => sc.Student) .WithMany(s => s.StudentCourses); modelBuilder.Entity<StudentCourse>() .HasOne<Course>(sc => sc.Course) .WithMany(s => s.StudentCourses);
- 3. Entity Framework Core Cheat Sheet 3 Viastudy.com Features EF Core DB-First - Command line 1.0 DB-First -VS Wizard X Identity Key Generation 1.0 Global query filter 2.0 DB Scalar function 2.0 Model-First X Code-First 1.0 Mixed client/server evaluation 1.0 DbContext & DbSet 1.0 LINQ-to-Entities 1.0 ChangeTracker 1.0 Automated Migration X Code-based Migration 1.0 Eager Loading 1.0 Proxy Entity X Interception X Simple Logging X GroupBy Transaction 2.1 Graphical Visualization X of EDM Raw SQL Queries: Entity Types 1.0 EDM Wizard X Raw SQL Queries: non- 2.1 Querying using EntitySQL X entity types DbContext Pooling 2.0 Table per hierarchy 1.0 Table per type X Data annotations 1.0 Fluent API 1.0 Table per concrete class X Model Format: EDMX X Many-to-Many without X join entity (XML) Entity Splitting X Spatial Data X Lazy loading 2.1 Stored procedure mapping with entity for X CUD operation Seed Data 2.1 Complex Type/Owned X types Table splitting 2.0 Field Mapping 1.1 Shadow properties 1.0 Alternate Keys 1.0