Removing (more than one) rows from table without fetching them from DB.

Hello!

How can I delete more than one row from table using LightSpeed without fetching them from table?

I've found one example in in UserGuide:

Alternatively, to delete data without needing to fetch the data for the entity first, use the following to delete any rows in your database that match the provided query object.

 

CopyRemove data that matches a LightSpeed Query

1 var query = new Query(typeof(Contribution)) {Identifier = 1};
2
3 _unitOfWork.Remove(query);
4 _unitOfWork.SaveChanges(true)

But this works only with one row.

In samples I've found delete sample but it deletes only one row too:

  QueryExpression query = Entity.Attribute("OrderID") == 10255;

  IList<OrderDetail> orderDetails = UnitOfWork.Find<OrderDetail>(query);

  UnitOfWork.Remove(orderDetails[0]);
  UnitOfWork.SaveChanges();

Maybe only solution for this is retrieve all rows which I want to delete and remove them from DB in FOR loop?

Thanks

Hi Webio,

The Remove() method will delete any rows matching that query.

For example, you could try deleting all rows by calling with a query such as Entity.Attribute("OrderID") != -1 which would match on everything (assuming the had to have an OrderID). Hopefully that helps clarify how you would do this.

Hope that helps,

John-Daniel

Thanks for answering but I have one more question: in example which I showed there is:

   UnitOfWork.Remove(orderDetails[0]);

I'm talking right now about index "[0]". Should it be used when removing more than one row?

For example:

QueryExpression query = Entity.Attribute("CategoryId") == 5; (CategoryId is not identity column)

IList<OrderDetail> orderByCategory = UnitOfWork.Find<OrderDetail>(query);

UnitOfWork.Remove(orderByCategory[0]); (by using index I'm assuming that I'm removing only one item from DB or maybe this must be done this way?)

UnitOfWork.SaveChanges(); 

 Thanks

 Hi Webio,

Calling UnitOfWork.Remove(orderByCategory[0]); will delete whatever entity is sitting at that index in the collection.

Be careful when doing this as if you ever change the order of items in your collection or if there is nothing in the collection you'll get an error.

I hope that makes sense and helps,

John-Danie