Add #448 possible breaking change.

Author: fredericDelaporte

releasenotes.txt

@@ -6,6 +6,19 @@ Release notes - NHibernate - Version 5.1.0
     ##### Possible Breaking Changes #####
         * Since Ingres9Dialect is now supporting sequences, the enhanced-sequence identifier generator will default to
           using a sequence instead of a table. Revert to previous behavior by using its force_table_use parameter.
+        * Some overridable methods of the Dialect base class and of MsSql2000Dialect have been obsoleted in favor of
+          new methods. Dialects implementors need to override the replacing methods if they were overriding the
+          obsolete ones, which are:
+          * Dialect.GetIfNotExistsCreateConstraint(Table table, string name), replaced by
+            GetIfNotExistsCreateConstraint(string catalog, string schema, string table, string name).
+          * Dialect.GetIfNotExistsCreateConstraintEnd(Table table, string name), replaced by
+            GetIfNotExistsCreateConstraintEnd(string catalog, string schema, string table, string name).
+          * Dialect.GetIfExistsDropConstraint(Table table, string name), replaced by
+            GetIfExistsDropConstraint(string catalog, string schema, string table, string name).
+          * Dialect.GetIfExistsDropConstraintEnd(Table table, string name), replaced by
+            GetIfExistsDropConstraintEnd(string catalog, string schema, string table, string name).
+          * MsSql2000Dialect.GetSelectExistingObject(string name, Table table), replaced by
+            GetSelectExistingObject(string catalog, string schema, string table, string name).
 
 **