Change or rename a column name without losing data with Entity Framework Core 2.0

EF Core creates its migrations by comparing your models to the current database snapshot (a c# class). It then uses this to create a migration file you can review. However, EF Core cannot always know if you replaced this column or created a new column. When you check your migration file, make sure there are no column drops, index drops (related to this column) etc. You can replace all these with something like this:

migrationBuilder.RenameColumn(
    name: "ColumnA",
    table: "MyTable",
    newName: "ColumnB");