Hi,

I have to keep a large number of long numbers associated with specified type of object (some my class has to have a references to those numbers). It's about a few thousands per object. In code it would be keep as Set<Long> (but that could be changed).

My idea was to make a long wrapper (MyLong):



and later:


but maybe a set/array of longs could be mapped directly using Hibernate or it can be done more efficiently?


Thanks for help
Marcin

You can use the element tag to map a collection of longs (so you can map Set<Long> instead of Set<MyLong>). See http://www.hibernate.org/hib_docs/v3/reference/en/html_single/#collections-ofvalues.

For more efficiency you could also try mapping a blob to an array of bytes and then convert this to and from an array of longs in java code. To map an array of bytes to a blob see binary at http://www.hibernate.org/hib_docs/v3/reference/en/html_single/#mapping-types-basictypes and at http://www.hibernate.org/hib_docs/v3/reference/en/html_single/#mapping-declaration-property. To convert to and from the byte array the second solution at http://java.ittoolbox.com/groups/technical-functional/java-l/long-to-byte-array-1229531# looks good in terms of lines of code but I'll leave that up to you. Good Luck!

Thanks, mapping with "element" tag works fine for Set<Long>.
In the next iteration I will try to optimize it following your suggestions.