Update transpilers.asciidoc Changes: - fixed non-working queries (queries which returned no results) - updated documentation with more examples in the limitations section - updated execution tags for queries which are for reference only - commented out the pattern filter examples for now
To Do: - fix OPTIONAL queries - fix Pattern filter queries - inspect and patch special cases in code Project: http://git-wip-us.apache.org/repos/asf/tinkerpop/repo Commit: http://git-wip-us.apache.org/repos/asf/tinkerpop/commit/5ec6f2fa Tree: http://git-wip-us.apache.org/repos/asf/tinkerpop/tree/5ec6f2fa Diff: http://git-wip-us.apache.org/repos/asf/tinkerpop/diff/5ec6f2fa Branch: refs/heads/TINKERPOP-1878 Commit: 5ec6f2fa88646bb2403580ce1679942cb45748ac Parents: 6513bcd Author: Harsh Thakkar <[email protected]> Authored: Fri Jun 15 11:24:57 2018 +0200 Committer: Stephen Mallette <[email protected]> Committed: Wed Jun 20 07:27:46 2018 -0400 ---------------------------------------------------------------------- docs/src/reference/transpilers.asciidoc | 94 +++++++++++++++++++++------- 1 file changed, 72 insertions(+), 22 deletions(-) ---------------------------------------------------------------------- http://git-wip-us.apache.org/repos/asf/tinkerpop/blob/5ec6f2fa/docs/src/reference/transpilers.asciidoc ---------------------------------------------------------------------- diff --git a/docs/src/reference/transpilers.asciidoc b/docs/src/reference/transpilers.asciidoc index 3211857..1bb7728 100644 --- a/docs/src/reference/transpilers.asciidoc +++ b/docs/src/reference/transpilers.asciidoc @@ -131,7 +131,7 @@ The current implementation of SPARQL-Gremlin transpiler (i.e. SPARQL-Gremlin) do * SPARQL queries with variables in the predicate position are not currently covered, with an exception of the following case: -[source,groovy] +[source,text] ---- g.sparql("""SELECT * WHERE { ?x ?y ?z . }""") ---- @@ -141,24 +141,72 @@ SPARQL query has the same number of patterns on both the side of the union opera SPARQL query cannot be mapped using Gremlinator, since a union is executed between different number of graph patterns (two patterns `union` 1 pattern). -[source,groovy] +[source,text] ---- -g.sparql("""SELECT * - WHERE { - {?person e:created ?software . - ?person v:name "daniel" .} +g.sparql("""SELECT * WHERE { + {?person e:created ?software . + ?person v:name "josh" .} UNION {?software v:lang "java" .} }""") ---- -* order by -.... -Adding more here... -.... +* A non-Group key variable cannot be projected in a SPARQL query. This is a SPARQL langauge limitation rather than that of Gremlin/TinkerPop. Apache Jena throws the exception " Non-group key variable in SELECT" if this occurs. +For instance, in a SPARQL query with GROUP-BY clause, only the variable on which the grouping is declared, can be projected. The following query is valid: + +[source,groovy] +---- +g.sparql("""SELECT ?age WHERE { + ?person v:label "person" . + ?person v:age ?age . + ?person v:name ?name .} GROUP BY (?age)""") +---- + +Whereas, the following SPARQL query will be invalid: + +[source,text] +---- +g.sparql("""SELECT ?person WHERE { + ?person v:label "person" . + ?person v:age ?age . + ?person v:name ?name .} GROUP BY (?age)""") +---- + + +* In a SPARQL query with an ORDER-BY clause, the ordering occurs wrt to the first projected variable in the query. You may choose any number of variable to be projected, however, the first variable in the selection will be the ordering decider. +For instance, in the query: + + +[source,groovy] +---- +g.sparql("""SELECT ?name ?age WHERE { + ?person v:label "person" . + ?person v:age ?age . + ?person v:name ?name . } ORDER BY (?age)""") +---- -* group by +the result set will be ordered according to the `?name` variable (in ascending order by default) despite having passed `?age` in the order by. Whereas, for the following query: + +[source,groovy] +---- +g.sparql("""SELECT ?age ?name WHERE { + ?person v:label "person" . + ?person v:age ?age . + ?person v:name ?name . } ORDER BY (?age)""") +---- + +the result set will be ordered according to the `?age` (as it is the first projected variable). Finally, for the select all case (`SELECT *`): + +[source,groovy] +---- +g.sparql("""SELECT * +WHERE { ?person v:label "person" . ?person v:age ?age . ?person v:name ?name . } ORDER BY (?age)""") +---- + +The the variable encountered first will be the ordering decider, i.e. since we have `?person` being encountered first, the result set will be ordered according to the `?person` variable (which are vertex id). + +* OPTIONAL .... -Adding more here... +currently fixing this... .... [[examples]] @@ -264,6 +312,7 @@ WHERE { FILTER (?age > 30 && ?lang = "java") }""") ---- +//// [[pattern-filters]] ==== Pattern Filter(s) @@ -288,6 +337,7 @@ WHERE { ?person v:name ?name . FILTER NOT EXISTS { ?person e:created ?project } }""") ---- +//// [[union]] ==== Union @@ -325,11 +375,12 @@ Select all vertices with the label `person` and order them by their age. [gremlin-groovy,existing] ---- -g.sparql("""SELECT * +g.sparql("""SELECT ?age ?name WHERE { ?person v:label "person" . ?person v:age ?age . -} ORDER BY (?age)""") + ?person v:name ?name . +} ORDER BY (?age)) ---- [[group-by]] @@ -337,9 +388,9 @@ WHERE { Select all vertices with the label `person` and group them by their age. -[source,groovy] +[gremlin-groovy,existing] ---- -g.sparql("""SELECT * +g.sparql("""SELECT ?age WHERE { ?person v:label "person" . ?person v:age ?age . @@ -354,7 +405,7 @@ the top two. [source,groovy] ---- -g.sparql("""SELECT COUNT(?project) +g.sparql("""SELECT (COUNT(?project) as ?p) WHERE { ?person v:label "person" . ?person v:age ?age . FILTER (?age < 30) @@ -388,12 +439,11 @@ can be perceived as path queries or neighborhood queries. For instance, getting [gremlin-groovy,existing] ---- -g.sparql("""SELECT ?age ?software ?name ?location ?startTime +g.sparql("""SELECT ?age ?software ?lang ?name WHERE { - ?person v:name "daniel" . + ?person v:name "josh" . ?person v:age ?age . ?person e:created ?software . - ?person p:location ?location . - ?location v:value ?name . - ?location v:startTime ?startTime }""") + ?software v:lang ?lang . + ?software v:name ?name . }""") ----
