Efcore: Column Created Time in EFMigrationsHistory

[fairking]

Can I add a column Time to the table __EFMigrationsHistory with a utc time of the created row populated.
As I can see at the moment there is a hard-coded HistoryRow which cannot be changed outside.

Any ideas are very welcome.

See the following example
```C#
public class CustomHistoryRepository : NpgsqlHistoryRepository
{
public CustomHistoryRepository(HistoryRepositoryDependencies dependencies)
: base(dependencies)
{
}

    protected override void ConfigureTable(EntityTypeBuilder<HistoryRow> history)
    {
        base.ConfigureTable(history);

        history
            .Property<DateTime>("Time")
            .HasValueGenerator<DateTimeUtcValueGenerator>()
            .ValueGeneratedOnAdd();
    }

    public override string GetInsertScript(HistoryRow row)
    {
        return base.GetInsertScript(row);
    }
}

```C#
var dbOptions = new DbContextOptionsBuilder(options)
                    .UseNpgsql(settings.DefaultConnection)
                    .ReplaceService<IHistoryRepository, CustomHistoryRepository>()
                    .Options;

Further technical details

EF Core version: Microsoft.AspNetCore.Identity.EntityFrameworkCore v.2.1.3
Database Provider: Npgsql.EntityFrameworkCore.PostgreSQL v.2.1.2
Operating system: Visual Studio 2017 Community v.15.8.7

[ajcvickers]

@bricelam to respond

[bricelam]

The entity type is currently only used for generating the CREATE TABLE statement. All other configuration is ignored.

You could generate the value in the database using a default value:

history
    .Property<DateTime>("Time")
    .HasDefaultValueSql("CURRENT_TIMESTAMP AT TIME ZONE 'UTC'");

Or you could manually change the INSERT statement. Note however, that this would do funny things when generating a SQL script form the migrations. The value would be the time you generated the script, not the time you actually applied the migration.

public override string GetInsertScript(HistoryRow row)
{
    var stringMapping = Dependencies.TypeMappingSource.GetMapping(typeof(string));
    var dateTimeMapping = Dependencies.TypeMappingSource.GetMapping(typeof(DateTime));

    return @"INSERT INTO ")
        .Append(SqlGenerationHelper.DelimitIdentifier(TableName, TableSchema))
        .Append(" (")
        .Append(SqlGenerationHelper.DelimitIdentifier(MigrationIdColumnName))
        .Append(", ")
        .Append(SqlGenerationHelper.DelimitIdentifier(ProductVersionColumnName))
        .Append(", ")
        .Append(SqlGenerationHelper.DelimitIdentifier("Time"))
        .AppendLine(")")
        .Append("VALUES (")
        .Append(stringMapping.GenerateSqlLiteral(row.MigrationId))
        .Append(", ")
        .Append(stringMapping.GenerateSqlLiteral(row.ProductVersion))
        .Append(", ")
        .Append(dateTimeMapping.GenerateSqlLiteral(DateTime.UtcNow))
        .Append(")")
        .AppendLine(SqlGenerationHelper.StatementTerminator)
        .ToString();
}

[bricelam]

Your code may also just work after we implement #2737.

[fairking]

Thanks Brice. Your solution with HasDefaultValueSql works fine. Did't know about HasDefaultValueSql as it was different namespace I had to add.