CreateDatabaseIfNotExists tries to initialize an existing database - database

Question

I am using CreateDatabaseIfNotExists when creating a database, but it just doesn't drop the database and then it starts initializing it.
There is my DbContext.
public class AppDbContext : DbContext
{
public AppDbContext() : base("Valtrends")
{
InitializeDbContext();
}
public DbSet<FactorType> FactorTypes { get; set; }
public DbSet<ComplexType> ComplexTypes { get; set; }
public DbSet<Value> Values { get; set; }
public DbSet<DataLoader.Entities.Version> Versions { get; set; }
public DbSet<DefaultPlotData> DefaultPlotData { get; set; }
public DbSet<GraphBucket> GraphBuckets { get; set; }
public DbSet<XfactorFrom> XfactorsFrom { get; set; }
public DbSet<XfactorTo> XfactorsTo { get; set; }
public DbSet<DistributionData> DistributionData { get; set; }
public DbSet<Bin> Bins { get; set; }
public DbSet<DefaultPlotSettings> DefaultPlotSettings { get; set; }
private void InitializeDbContext()
{
Database.SetInitializer(new AppDbInitializer());
}
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Entity<FactorType>().HasMany(m => m.CompatibilityListXY).WithMany();
}
}
}
And there is the the first part of my AppDbInitializer.
public class AppDbInitializer : CreateDatabaseIfNotExists<AppDbContext>//DropCreateDatabaseAlways<AppDbContext>
{
public override void InitializeDatabase(AppDbContext context)
{
base.InitializeDatabase(context);
var jsonImporter = new JsonImporter();
List<DataLoader.Entities.Version> versions = (jsonImporter.ImportFromJson<List<DataLoader.Entities.Version>>("Versions.json"));
context.Versions.AddRange(versions);
context.SaveChanges();
After SaveChanges I get a violation of primary keys exception on the entity version.

Answer 1

I am using CreateDatabaseIfNotExists when creating a database, but it just doesn't drop the database and then it starts initializing it
It never drops an existing database. As the name implies, it checks if database exists, and if yes, it does nothing, otherwise it creates and initializes it.
Also note that the InitializeDatabase method of the IDatabaseInitializer is always called, it's the class that implements it responsibility what actual action to perform.
In your case you incorrectly assume that the base method will always create the new database, which is not the case. If you want to add a code that executes only when a new database is created, then you should override the Seed method instead:
public class AppDbInitializer : CreateDatabaseIfNotExists<AppDbContext>
{
protected override void Seed(AppDbContext context)
{
var jsonImporter = new JsonImporter();
List<DataLoader.Entities.Version> versions = (jsonImporter.ImportFromJson<List<DataLoader.Entities.Version>>("Versions.json"));
context.Versions.AddRange(versions);
context.SaveChanges(); // you don't need this, it's automatically called after `Seed` call
}
}