Tips and tricks

Question

Post your Tips here  -- Please use good subjects

Thanks

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Tonyp

Answer 1

Maximum number of entities returned (page size):

SSDS returns a maximum of 500 entities for a query result.  The result list is always ordered by the entity ID.    


Entity order in query result:

A query result is always ordered by entity IDs.

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Tonyp

Answer 2

How to get more than 500 entities in a query result:

If a query has a result set smaller or equal to 500 then you get all the results of the query in one page.  If a query has more than 500 entities in the result set then you need to run the query multiple times to get all the results (500 at a time).  Since the query always returns the results in order of Entity ID you can use the last entity ID as a filter for the next query.  Here is a sample code section:

 

string lastId = "";
string query = @"from e in entities where e[""Someprop""]== ""Some Value"" && e.Id > ""{0}"" select e";
while (true)
{
  int count = 0;
  foreach (Entity entity in proxy.Query(myContainerScope, String.Format(query, lastId))
  {
     // Do something with entities
     …
     lastId = entity.Id;
     count++;
  }
  if (count < 500)
    break;    // last page if less than 500 results
} 

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Tonyp

Answer 3

Since Ids are always strings we get results ordered non-numerically (e.g. 1, 100, 101).  Any way to do casting with SSDS to cast it to a int to get proper ordering?  Not that ordering by Id is important but it would be useful in other situations.

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http://www.silverlight-tour.com

Answer 4

Shawn
Is this still on your radar!!

Anil

Answer 5

 

Shawn Wildermuth said:

Since Ids are always strings we get results ordered non-numerically (e.g. 1, 100, 101).  Any way to do casting with SSDS to cast it to a int to get proper ordering?  Not that ordering by Id is important but it would be useful in other situations.

Shawn, you can accomplish this by zero padding your Id's so they follow the pattern 000001, ... 000100, etc.    This is the same trick you'll see for naming images on your digital camera and it sorts in "numeric order".

Nigel.

Answer 6

 

Tony Petrossian said:

A query result is always ordered by entity IDs.

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Tonyp

This is not true - SDS supports orderby in the query syntax, and when that is used, results are ordered by the criteria that you state.  This means that SDS entities are not always ordered by entity IDs, and the code snippet used earlier in this tip to page will not work for ordered queries.

Shan McArthur
www.shanmcarthur.net