text: -- Licensed to the Apache Software Foundation (ASF) under one or more
  -- contributor license agreements.  See the NOTICE file distributed with
  -- this work for additional information regarding copyright ownership.
  -- The ASF licenses this file to You under the Apache License, Version 2.0
  -- (the "License"); you may not use this file except in compliance with
  -- the License.  You may obtain a copy of the License at
  --
  --      http://www.apache.org/licenses/LICENSE-2.0
  --
  -- Unless required by applicable law or agreed to in writing, software
  -- distributed under the License is distributed on an "AS IS" BASIS,
  -- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  -- See the License for the specific language governing permissions and
  -- limitations under the License.
  
  UPDATE metadata SET mvalue = '2' WHERE mkey = 'version';
  
  -- update nodes.svalue to longtext
  ALTER TABLE nodes MODIFY svalue LONGTEXT NOT NULL;
  
  ALTER TABLE nodes ADD CONSTRAINT nodes_unique UNIQUE (ntype,svalue);
  
  -- drop not null on triples.context
  ALTER TABLE triples MODIFY context bigint     REFERENCES nodes(id);
  