Why do I get an error when creating a SQLite database in C#?

Question

SQLite

Created two models and a data context. I made a migration (Add-Migration Initial) and executed the command to create a database (Update-Database), the database was created, but an error occurs when it is opened. The question is why, I broke my whole head, I can’t work normally with SQLite and EF.


Here are the models and context:

class Phone
    {
        public int Id { get; set; }
        public string Name { get; set; }
        public string Title { get; set; }


        [ForeignKey("CompanyId")]
        public virtual Company Company { get; set; }


        public Phone(string Name, string Title)
        {
            this.Name = Name;
            this.Title = Title;
        }

        public override string ToString()
        {
            return $"{Name} {Title}";
        }
    }

class Company
    {
        public int Id { get; set; }
        public string Name { get; set; }

        public virtual List<Phone> Phones { get; set; }

        public override string ToString()
        {
            return Name;
        }
    }

class Context : DbContext
    {
        public DbSet<Company> Companies { get; set; }
        public DbSet<Phone> Phones { get; set; }

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

        protected override void OnModelCreating(ModelBuilder modelBuilder)
        {
            modelBuilder.Entity<Company>().ToTable("Companies");
            modelBuilder.Entity<Phone>().ToTable("Phones");
        }
    }

Here is the migration:

protected override void Up(MigrationBuilder migrationBuilder)
        {
            migrationBuilder.CreateTable(
                name: "Companies",
                columns: table => new
                {
                    Id = table.Column<int>(nullable: false)
                        .Annotation("Sqlite:Autoincrement", true),
                    Name = table.Column<string>(nullable: true)
                },
                constraints: table =>
                {
                    table.PrimaryKey("PK_Companies", x => x.Id);
                });

            migrationBuilder.CreateTable(
                name: "Phones",
                columns: table => new
                {
                    Id = table.Column<int>(nullable: false)
                        .Annotation("Sqlite:Autoincrement", true),
                    Name = table.Column<string>(nullable: true),
                    Title = table.Column<string>(nullable: true),
                    CompanyId = table.Column<int>(nullable: true)
                },
                constraints: table =>
                {
                    table.PrimaryKey("PK_Phones", x => x.Id);
                    table.ForeignKey(
                        name: "FK_Phones_Companies_CompanyId",
                        column: x => x.CompanyId,
                        principalTable: "Companies",
                        principalColumn: "Id",
                        onDelete: ReferentialAction.Restrict);
                });

            migrationBuilder.CreateIndex(
                name: "IX_Phones_CompanyId",
                table: "Phones",
                column: "CompanyId");
        }

        protected override void Down(MigrationBuilder migrationBuilder)
        {
            migrationBuilder.DropTable(
                name: "Phones");

            migrationBuilder.DropTable(
                name: "Companies");
        }

Answer 1

Maybe you haven't closed the studio and it's locking the file, or maybe you're using version 2 instead of version 3.
Check it all out.
UPD, add a constructor and check whether the tables were created in it.
public Context()
{
Database.EnsureCreated();
}