Seeder method for Azure Database in EF Core 2 - azure

Question

What is the proper method to seed data into an Azure Database? Currently in development I have a seeder method that inserts the first couple of users as well as products. The Users (including admin user) username and password are hardcoded into the Seed method, is this an acceptable practice?
As far as the products are concerned, I have a json file with the product names and descriptions - which in development the seeder method iterates through and inserts the data.

Answer 1

To answer your question "The Users (including admin user) username and password are hardcoded into the Seed method, is this an acceptable practice?"
No you should keep your password in cleartext format, though you can keep it it encrypet mode and seed it.
In EF Core 2.1, the seeding workflow is quite different. There is now Fluent API logic to define the seed data in OnModelCreating. Then, when you create a migration, the seeding is transformed into migration commands to perform inserts, and is eventually transformed into SQL that that particular migration executes. Further migrations will know to insert more data, or even perform updates and deletes, depending on what changes you make in the OnModelCreating method.
Suppose thethree classes in my model are Magazine, Article and Author. A magazine can have one or more articles and an article can have one author. There’s also a PublicationsContext that uses SQLite as its data provider and has some basic SQL logging set up.
Let take an example of single entity type.
Let’s start by seeing what it looks like to provide seed data for a magazine—at its simplest.
The key to the new seeding feature is the HasData Fluent API method, which you can apply to an Entity in the OnModelCreating method.
Here’s the structure of the Magazine type:
public class Magazine
{
public int MagazineId { get; set; }
public string Name { get; set; }
public string Publisher { get; set; }
public List<Article> Articles { get; set; }
}
It has a key property, MagazineId, two strings and a list of Article types. Now let’s seed it with data for a single magazine:
protected override void OnModelCreating (ModelBuilder modelBuilder)
{
modelBuilder.Entity<Magazine> ().HasData
(new Magazine { MagazineId = 1, Name = "MSDN Magazine" });
}
A couple things to pay attention to here: First, I’m explicitly setting the key property, MagazineId. Second, I’m not supplying the Publisher string.
Next, I’ll add a migration, my first for this model. I happen to be using Visual Studio Code for this project, which is a .NET Core app, so I’m using the CLI migrations command, “dotnet ef migrations add init.” The resulting migration file contains all of the usual CreateTable and other relevant logic, followed by code to insert the new data, specifying the table name, columns and values:
migrationBuilder.InsertData(
table: "Magazines",
columns: new[] { "MagazineId", "Name", "Publisher" },
values: new object[] { 1, "MSDN Magazine", null });
Inserting the primary key value stands out to me here—especially after I’ve checked how the MagazineId column was defined further up in the migration file. It’s a column that should auto-increment, so you may not expect that value to be explicitly inserted:
MagazineId = table.Column<int>(nullable: false)
.Annotation("Sqlite:Autoincrement", true)
Let’s continue to see how this works out. Using the migrations script command, “dotnet ef migrations script,” to show what will be sent to the database, I can see that the primary key value will still be inserted into the key column:
INSERT INTO "Magazines" ("MagazineId", "Name", "Publisher")
VALUES (1, 'MSDN Magazine', NULL);
That’s because I’m targeting SQLite. SQLite will insert a key value if it’s provided, overriding the auto-increment. But what about with a SQL Server database, which definitely won’t do that on the fly?
I switched the context to use the SQL Server provider to investigate and saw that the SQL generated by the SQL Server provider includes logic to temporarily set IDENTITY_INSERT ON. That way, the supplied value will be inserted into the primary key column. Mystery solved!
You can use HasData to insert multiple rows at a time, though keep in mind that HasData is specific to a single entity. You can’t combine inserts to multiple tables with HasData. Here, I’m inserting two magazines at once:
modelBuilder.Entity<Magazine>()
.HasData(new Magazine{MagazineId=2, Name="New Yorker"},
new Magazine{MagazineId=3, Name="Scientific American"}
);
For a complete example , you can browse through this sample repo
Hope it helps.