Do you have more than 10 properties? Might be that one row is not enough in the bigtable to store all properties (or that you have too many string properties). Are you only curious about this or do you have any problems when retrieving the data?
Frederik
What Subtype is created?
Perhaps you are seeing some other class that has references to Students, for example a "Class" class which has a List<Student> ?
The Student class you presented above should not get anything stored in tblBigTableReference.
/johan
Hi Frederik
You are right I am having more than 10 properties in the class, but how do you know bigtable will create another reference row if the class has more than 10 properties (that's the thing I disklike the CMS which has a lot of hidden stuffs in it without proper documentation)? I don't have any problem regarding to create another reference row (just a little bit concern about the performance).
The bigtable only has x columns of each type (you can easily see how many in the schema) and you seem to have a lot of string properties so you probably hit the limit of varchar fields available so it has to span multiple rows. This is probably what Frederik meant, just wanted to clarify that it is dependent on the type of data.
@vincent yang
Direct from the DDS Tech note:
"You may add and remove columns in this table to suit the type of data you are saving. This may be particularly useful if you know you are going to store a data type with more than say 10 strings for example. By default the 11th to 20th strings would be stored in a 2nd row for the type which means a join has to be done at runtime when reading the data. By adding String11, String12 etc to the ‘big table’ you limit the chance of a row overspill and therefore increase performance. If you require more indexes then add columns with names starting with 'Indexed' and ensure an index is created on them."
Maybe you can read the proper documentation before claiming it doesn't exist
I had a simple poco class which only contains a set of primitive type properties. According to online documentation, "All properties that cannot be mapped inline or as a collection (plus the EPiServer.Data.Dynamic.PropertyBag type) are mapped as references", as far as I can see all my properties are inline type, why it still creates the subtype and a link row is added in the reference table to link the parent data?