Entity Framework Extensions Column Output Expression

The ColumnOutputExpression allows you to choose specific properties in which you want to retrieve data from the database.

The following example uses IsActive property in the ColumnInputExpression and Name and IsActive properties in the ColumnOutputExpression.

  • It will insert data only in the IsActive field and all other properties will remain NULL in the database.
  • In the ColumnOutputExpression, Name and IsActive properties are specified so it will update the specified properties from the database to the list.
using (var context = new EntityContext())
{
    context.BulkInsert(list, options => {
        options.ColumnOutputExpression = c => new { c.Name, c.IsActive };
        options.ColumnInputExpression = c => new { c.IsActive };
    });
}
  • Now as result you will see the Name property is null, that is because we have inserted data only for IsActive, and the Name field remains null in the database.
  • When the list was updated from the database, it replaces the value of Name and IsActive from the database and Name is NULL to the database.
  • The Description property is unchanged because it is not updated from the database.

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