example_4.bql

# Copyright 2016 Google Inc. All rights reserved.
#
# Licensed 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.

# Create graph.
CREATE GRAPH ?info;

# Insert some data into the ?info graph.
INSERT DATA INTO ?info {
  /u<joe>   "bought"@[2016-01-01T00:00:00-08:00]  /car<model x> .
  /u<mary>  "bought"@[2018-01-01T00:00:00-08:00]  /car<model y> .
  /u<joe>   "bought"@[2020-01-01T00:00:00-08:00]  /car<model z> .
  /u<bob>   "bought"@[2021-01-01T00:00:00-08:00]  /car<model x> .
  /u<joe>   "meet"@[2012-01-01T00:00:00-08:00]    /u<mary> .
  /u<bob>   "meet"@[2014-01-01T00:00:00-08:00]    /u<joe> .
  /u<joe>   "height_cm"@[]                        "172"^^type:int64 .
  /u<mary>  "height_cm"@[]                        "174"^^type:int64 .
  /u<bob>   "height_cm"@[]                        "168"^^type:int64 .
  /_<bn1>   "_predicate"@[]                       "bought"@[2018-01-01T00:00:00-08:00] .
  /_<bn2>   "_predicate"@[]                       "height_cm"@[]
};

# What are all the immutable triples of the ?info graph?
SELECT ?s, ?p, ?o
FROM ?info
WHERE {
  ?s ?p ?o .
  FILTER isImmutable(?p)
};

# What are all the temporal triples of the ?info graph?
SELECT ?s, ?p, ?o
FROM ?info
WHERE {
  ?s ?p ?o .
  FILTER isTemporal(?p)
};

# What is all the information we have regarding the latest "bought"
# event in our graph? (Who was the last to buy what, and when?)
SELECT ?s, ?p, ?o
FROM ?info
WHERE {
  ?s "bought"@[?time] AS ?p ?o .
  FILTER latest(?p)
};

# What are the latest triples of each time series present in the ?info
# graph?
SELECT ?s, ?p, ?o
FROM ?info
WHERE {
  ?s ?p ?o .
  FILTER latest(?p)
};
# (note how "latest" automatically skips the immutable triples).

# What are the triples of the ?info graph for which the object is an
# immutable predicate (eg: reification scenario)?
SELECT ?s, ?p, ?o
FROM ?info
WHERE {
  ?s ?p ?o .
  FILTER isImmutable(?o)
};

# Drop graph.
DROP GRAPH ?info;