support openCypher-like relationsiop-type edge alternation#2468
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eeshwarg wants to merge 1 commit into
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support openCypher-like relationsiop-type edge alternation#2468eeshwarg wants to merge 1 commit into
eeshwarg wants to merge 1 commit into
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Apache AGE's MATCH grammar rejects openCypher's relationship-type alternation syntax -
`MATCH ()-[:A|B]->()` fails at parse time with `syntax error at or near "|"`. For example,
a query like `SELECT * FROM cypher('kg_s7', $$ MATCH (p)-[:WORKS_AT|REPORTS_TO]->(c) RETURN c $$) AS (c agtype);`
throws a syntax error. A workaround for this today is to run something like
`SELECT * FROM cypher('kg_s7', $$ MATCH (p)-[r]->(c) WHERE type(r) IN ['WORKS_AT','REPORTS_TO'] RETURN c $$) AS (c agtype);`.
This change enables support for relationship-type alternation in accordance with the openCypher
standard. Changes are made in the grammar, AST and during transformation from the AST to Postgres
`Query` struct by adding the types to the `quals` list.
Variable-length relationship patterns with alternation `([:A|B*1..2])` are explicitly rejected
with `ERRCODE_FEATURE_NOT_SUPPORTED`.
Testing:
- Added regress test with cases with directed/undirected edges, and variable length edges
Future work:
- openCypher also support node-type alternation (like n:Person|Customer), which could be
added to AGE in a future PR
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Apache AGE's MATCH grammar rejects openCypher's relationship-type alternation syntax -
MATCH ()-[:A|B]->()fails at parse time withsyntax error at or near "|". For example, a query likeSELECT * FROM cypher('kg_s7', $$ MATCH (p)-[:WORKS_AT|REPORTS_TO]->(c) RETURN c $$) AS (c agtype);throws a syntax error. A workaround for this today is to run something likeSELECT * FROM cypher('kg_s7', $$ MATCH (p)-[r]->(c) WHERE type(r) IN ['WORKS_AT','REPORTS_TO'] RETURN c $$) AS (c agtype);.This change enables support for relationship-type alternation in accordance with the openCypher standard. Changes are made in the grammar, AST and during transformation from the AST to Postgres
Querystruct by adding the types to thequalslist.Variable-length relationship patterns with alternation
([:A|B*1..2])are explicitly rejected withERRCODE_FEATURE_NOT_SUPPORTED.Testing:
Future work: