Views and null table name

[awjacobson]

I am looking for an example or help on using views along side temporal tables. My current implementation results in an exception when updating the database.

I have used PreventTemporalTables so that only specific tables are made temporal:

protected override void OnModelCreating(ModelBuilder modelBuilder)
{
    base.OnModelCreating(modelBuilder);
    modelBuilder.PreventTemporalTables();
    modelBuilder.ApplyConfigurationsFromAssembly(Assembly.GetExecutingAssembly());
    SeedDb.Seed(modelBuilder);
}

I have configured my views as follows:

public class OtherEntityStatesConfiguration : IEntityTypeConfiguration<OtherEntityState>
{
    public void Configure(EntityTypeBuilder<OtherEntityState> builder)
    {
        builder.HasNoKey();
        builder.ToView("View_OtherEntityStates");
    }
}

When I execute dotnet ef database update then I receive this exception:

System.ArgumentNullException: Value cannot be null. (Parameter 'Table name not initialized')
   at EntityFrameworkCore.TemporalTables.Sql.Generation.BaseTemporalTableSqlGenerator..ctor(String tableName, String schemaName)
   at EntityFrameworkCore.TemporalTables.Sql.Generation.NoSqlTemporalTableGenerator..ctor(String tableName, String schemaName)
   at EntityFrameworkCore.TemporalTables.Sql.Factory.TemporalTableSqlGeneratorFactory.CreateInstance(Boolean isEntityConfigurationTemporal, Boolean isEntityTemporalInDatabase, String tableName, String schemaName)
   at EntityFrameworkCore.TemporalTables.Sql.TemporalTableSqlBuilder`1.BuildTemporalTableSqlFromEntityTypeConfiguration(IEntityType entityType, Boolean appendSeparator)
   at EntityFrameworkCore.TemporalTables.Sql.TemporalTableSqlBuilder`1.BuildTemporalTablesSqlForEntityTypes(IEnumerable`1 entityTypes, Boolean appendSeparator)
   at EntityFrameworkCore.TemporalTables.Sql.TemporalTableSqlBuilder`1.BuildTemporalTablesSql(Boolean appendSeparator)
   at EntityFrameworkCore.TemporalTables.Sql.TemporalTableSqlExecutor`1.Execute()
   at EntityFrameworkCore.TemporalTables.Migrations.TemporalTableMigrator`1.Migrate(String targetMigration)
   at EntityFrameworkCore.TemporalTables.Migrations.TemporalTableMigratorResolver.Migrate(String targetMigration)
   at Microsoft.EntityFrameworkCore.Design.Internal.MigrationsOperations.UpdateDatabase(String targetMigration, String connectionString, String contextType)
   at Microsoft.EntityFrameworkCore.Design.OperationExecutor.UpdateDatabaseImpl(String targetMigration, String connectionString, String contextType)
   at Microsoft.EntityFrameworkCore.Design.OperationExecutor.UpdateDatabase.<>c__DisplayClass0_0.<.ctor>b__0()
   at Microsoft.EntityFrameworkCore.Design.OperationExecutor.OperationBase.Execute(Action action)

I can see the null check in the constructor that generates the exception but I am not seeing a way to get around it:

public BaseTemporalTableSqlGenerator(string tableName, string schemaName = "dbo")
{
    this.tableName = tableName;
    this.schemaName = schemaName;

    if (string.IsNullOrWhiteSpace(tableName))
    {
        throw new ArgumentNullException("Table name not initialized");
    }

[awjacobson]

I bypassed this logic when the table name is null and it seems to have fixed my issue on the surface. I do not know if this breaks something else???

private string BuildTemporalTableSqlFromEntityTypeConfiguration(IEntityType entityType, bool appendSeparator)
{
    StringBuilder sqlBuilder = new StringBuilder();

    var relationalEntityType = context.Model.FindEntityType(entityType.Name);
    if (relationalEntityType is IEntityType)
    {

      string tableName = relationalEntityType.GetTableName();
      if (tableName is not null) // the above returns null if not mapped to a table (views)
      {
            string schema = relationalEntityType.GetSchema() ?? "dbo";

            bool isEntityConfigurationTemporal = TemporalEntitiesCache.IsEntityConfigurationTemporal(entityType);
            bool isEntityTemporalInDatabase = tableHelper.IsTableTemporal(tableName, schema);

            ITemporalTableSqlGenerator temporalTableSqlGenerator = temporalTableSqlGeneratorFactory
                .CreateInstance(isEntityConfigurationTemporal, isEntityTemporalInDatabase, tableName, schema);

            string temporalTableSql = temporalTableSqlGenerator.Generate();

            if (!string.IsNullOrWhiteSpace(temporalTableSql))
            {
                sqlBuilder.AppendLine(temporalTableSql);

                if (appendSeparator)
                {
                    sqlBuilder.AppendLine(new string('-', 100));
                }
            }
        }
    }
    return sqlBuilder.ToString();
}

[PeteCozens]

I've been having the same issue with views and independently came to the same conclusion.

This doesn't appear to break anything else - any chance of getting the change added to the master?

[awjacobson]

I've been having the same issue with views and independently came to the same conclusion.

This doesn't appear to break anything else - any chance of getting the change added to the master?

Hi Pete, you are in luck! The master branch has been updated

[tb1b]

I came across the same issue. Any time soon it's available in nuget?

[PeteCozens]

I came across the same issue. Any time soon it's available in nuget?

I just downloaded the code and added the project to my solution so as I can continue work on my project. Once the NuGet's updated I'll use that instead.

[PeteCozens]

Any chance of getting an updated version of this package published to NuGet?