Disallow usage of paged_delete in paged_operations plugin on Oracle w…

…ith emulated offsets

The approach used does not work correctly in that environment.

lib/sequel/plugins/paged_operations.rb

@@ -119,6 +119,9 @@ def paged_datasets(opts=OPTS)
         # :rows_per_page :: The maximum number of rows affected by each DELETE query
         #                   (unless concurrent modifications are made to the table).
         def paged_delete(opts=OPTS)
+          if db.database_type == :oracle && !supports_fetch_next_rows?
+            raise Error, "paged_delete is not supported on Oracle when using emulated offsets"
+          end
           pk = _paged_operations_pk(:paged_delete)
           rows_deleted = 0
           offset_ds = _paged_operations_offset_ds(opts)

spec/extensions/paged_operations_spec.rb

@@ -189,6 +189,14 @@
     proc{ds.offset(1).paged_datasets{}}.must_raise Sequel::Error
   end
 
+  it "should raise error paged_delete for Oracle with emulated offsets" do
+    db = Sequel.mock('oracle')
+    def db.server_version; 11020002; end
+    @c.dataset = db[:t]
+    ds = @c.dataset
+    proc{ds.offset(1).paged_delete}.must_raise Sequel::Error
+  end
+
   it "should raise error for dataset with offset" do
     proc{@ds.offset(1).paged_delete}.must_raise Sequel::Error
     proc{@ds.offset(1).paged_update(:x=>1)}.must_raise Sequel::Error

spec/integration/plugin_test.rb

@@ -3048,7 +3048,7 @@ def set(k, v, ttl) self[k] = v end
     end
     @model.paged_delete.must_equal 100
     @model.count.must_equal 0
-  end
+  end unless (DB.database_type == :oracle && !DB.dataset.supports_fetch_next_rows?)
 
   it "Model#paged_update should work on unfiltered dataset" do
     expected = 100.times.map{|i| [i+1, i+200]}
@@ -3089,7 +3089,7 @@ def set(k, v, ttl) self[k] = v end
     ds.paged_delete.must_equal 49
     ds.count.must_equal 0
     @model.count.must_equal 51
-  end
+  end unless (DB.database_type == :oracle && !DB.dataset.supports_fetch_next_rows?)
 
   it "Model#paged_update should work on filtered dataset" do
     ds = @model.where{id < 50}