“Binary schema evolution” (BSE) is a feature that allows an application to alter the database schema of a stored database image to a new definition contained in the dictionary of the currently running application.
Supported schema changes include:
a. Adding new classes
b. Dropping classes
c. Adding new fields to a class
d. Dropping fields from a class
e. Changing the type of a field (a loss of precision, e.g. INT2 to INT4 is allowed but may cause loss of precision; there is no error or warning)
f. Adding/dropping indexes
g. Adding/dropping fields from existing indexes
h. Changing an index from unique to allowing duplicates (and vice-versa, but duplicates will be dropped and mco_db_load() will return MCO_S_DUPLICATE; there is no mechanism to determine which record(s) with the duplicate value were omitted and which record was preserved).
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