How to get the number of rows in a table?

Question

SQL

The base model from the example looks like this:

using Microsoft.EntityFrameworkCore;
using System.Collections.Generic;

namespace ConsoleApp.SQLite
{
    public class BloggingContext : DbContext
    {
        public DbSet<Blog> Blogs { get; set; }
        public DbSet<Post> Posts { get; set; }

        protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
        {
            optionsBuilder.UseSqlite("Data Source=blogging.db");
        }
    }

    public class Blog
    {
        public int BlogId { get; set; }
        public string Url { get; set; }

        public List<Post> Posts { get; set; }
    }

    public class Post
    {
        public int PostId { get; set; }
        public string Title { get; set; }
        public string Content { get; set; }

        public int BlogId { get; set; }
        public Blog Blog { get; set; }
    }
}

You need to initialize the Blog[] blogs array and populate it with values ​​from db.Blogs. But in order to initialize the array, you need to find out how long it should be or how many rows are contained in db.Blogs, how to do this?

Answer 1

If there is already data in the DbSet, then you can get an array like this:
If you need to explicitly count the records, you can execute a scalar like this :

var command = new SQLiteCommand(connection);
command.CommandText = "SELECT COUNT(Id) FROM Blogs";
command.CommandType = CommandType.Text;
int сount = (int) command.ExecuteScalar();
Blog[] blogs = new Blogs[count];