Generating seed code from existing database in ASP.NET MVC

Question

I wondered if anyone has encountered a similar challenge:

I have a database with some data that was ETL\'ed (imported and transformed) in there from an Excel file. I

Answer 1

Lets say we have a simple database table with 3750 records in it;

| Id   | Age | FullName        |
|------|-----|-----------------|
| 1    | 50  | Michael Jackson |
| 2    | 42  | Elvis Presley   |
| 3    | 48  | Whitney Houston |
| ...  | ... | ...             |
| 3750 | 57  | Prince          |

We want to create this table in our database with using auto-generated Configuration.cs file and its Seed() method.

protected override void Seed(OurDbContainer context)
{
    context.GreatestSingers.AddOrUpdate(
            p => p.Id,
            new GreatestSinger { Id = 1, Age = 50, FullName = "Michael Jackson" },
            new GreatestSinger { Id = 2, Age = 42, FullName = "Elvis Presley" },
            new GreatestSinger { Id = 3, Age = 48, FullName = "Whitney Houston" }
            );
}

This is what you should do. 3750 times!

But you already have this data in your existing database table. So we can use this existing data to create Seed() codes.

With the help of SQL String Concatenation;

SELECT
CONCAT('new GreatestSinger { Id = ', Id ,', Age = ', Age ,', FullName = "', FullName ,'" },') 
FROM GreatestSinger

will give us all the code needed to create 3750 rows of data.

Just copy/paste it into Seed() method. And from Package Manager Console;

Add-Migration SeedDBwithSingersData

Update-Database