These are the limittions for virtually-hashed tables:
truncate table is not supported. Use delete from table table_name instead.
SQL92 does not allow two unique constraints on a relation to have the same key columns. However, the primary key clause for a virtually-hashed table is not a standard unique constraint, so you can declare a separate unique constraint with the same key columns as the virtually-hashed keys.
Because you cannot create a virtually-hashed clustered index after you create a table, You also cannot drop a virtually-hashed clustered index.
You must create a virtually-hashed table on an exclusive segment. You cannot share disk devices you assign to the segments for creating a virtually-hashed table with other segments.
You cannot create two virtually-hashed tables on the same exclusive segment. Adaptive Server supports 32 different segments per database. Three segments are reserved for the default, system and log segments, so the maximum number of virtually-hashed tables per database is 29.
You cannot use the alter table or drop clustered index commands on virtually-hashed tables.
Virtually-hashed tables must use all-pages locking (APL).
The key columns and hash factors of a virtually-hashed table must use the int datatype.
You cannot include text or image columns in virtually-hashed tables, or columns with datatypes based on the text or image datatypes.
Do not create virtually-hashed tables that :
Have frequent inserts and updates
Use frequent table scans
