来自文件的实体框架核心种子大数据

Question

In EF Core 2.1 I can seed data this way:

modelBuilder.Entity<Company>().HasData(
  new Company {.....},
  new Company {.....});

But I need to seed a text file with a large amount of rows (about 70k). What do you recommend me to achieve this?

Answer 1

What format is the data in this text file in?

If it's in JSON, you could do something like:

var companies = new List<Company>();
using (StreamReader r = new StreamReader(@"C:\temp\data.json"))
{
    string json = r.ReadToEnd();
    companies = JsonConvert.DeserializeObject<List<Company>>(json);
}

foreach(var company in companies)
    dbContext.Companies.Add(company);

dbContext.SaveChanges();

Answer 2

Ok, here's a pretty good explanation: Parsing Tab delimited text files

Just add your inserts into the database after each "record".