Code-First Approach
An alternative to introspecting the model from the provider is to handwrite your model classes. This is the code-first approach to Entity Framework, which gives you greater control over the exact data model you use in your application.
Create the Context Class
This is the base object that extends DbContext and exposes the DbSet properties that represent the tables in the data source. Override some of the default functionality of the DbContext class by overriding the OnConfiguring method.
using Microsoft.EntityFrameworkCore; public class ApacheKafkaContext : DbContext { public DbSet<SampleTable_1> SampleTable_1 { get; set; } protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder) { if (!optionsBuilder.IsConfigured) { optionsBuilder.UseApacheKafka("User=admin;Password=pass;BootStrapServers=localhost:9091"); } } }
Create the Table Models
Define a class for each table that was defined in the DbSet properties of the context class. The table classes should have a list of properties that correspond to each field of that table. A corresponding map class must be defined to configure attributes for each property in the table class.
public class SampleTable_1 { public string Id { get; set; } public string Column1 { get; set; } }
Retrieving Records
You can retrieve records from a table as follows:
class Program { static void Main(string[] args) { SalesforceContext context = new SalesforceContext();var Query = from Lead in context.Leadselect Lead; foreach (var result in Query) { Console.WriteLine("{0}", result.Id); Console.WriteLine("{0}", result.LastName); } try { context.SaveChanges(); } catch (Exception e) { Console.WriteLine(e); } Console.ReadLine(); } }
Inserting Records
You can insert records into existing tables as follows:
class Program { static void Main(string[] args) { SalesforceContext context = new SalesforceContext(); Lead newRecord = new Lead() { Company = "Company", LastName = "Iris1" }; context.Lead.Add(newRecord); try { context.SaveChanges(); Console.WriteLine(newRecord.Id); } catch (Exception e) { Console.WriteLine(e); } Console.ReadLine(); } }