A.10.1 PGQL Features Supported in Property Graph Schema

PGQL is a SQL-like query language for querying property graph data. It is based on the concept of graph pattern matching and allows you to specify, among other things, topology constraints, paths, filters, sorting and aggregation.

The Java API for PGQL defined in the oracle.pg.rdbms.pgql package supports the PGQL specification with a few exceptions. (Refer to the PGQL Specification).

The following table describes the list of supported and unsupported PGQL features:

Table A-1 Supported PGQL Features and Limitations for PG Schema Graphs

Feature	PG Schema
CREATE PROPERTY GRAPH	Supported
DROP PROPERTY GRAPH	Supported
Fixed-length pattern matching	Supported
Variable-length pattern matching goals	Supported: Reachability Limitations: ANY ANY SHORTEST TOP k SHORTEST ALL SHORTEST ANY CHEAPEST TOP k CHEAPEST ALL
Variable-length pattern matching quantifiers	Supported: * + ? { n } { n, } { n, m } { , m }
Variable-length path unnesting	Not supported
GROUP BY	Supported
HAVING	Supported
Aggregations	Supported: COUNT MIN, MAX, AVG, SUM Limitations: LISTAGG ARRAY_AGG
DISTINCT SELECT DISTINCT Aggregation with DISTINCT (such as, COUNT(DISTINCT e.prop))	Supported
SELECT v.*	Not Supported
ORDER BY (+ASC/DESC), LIMIT, OFFSET	Supported
Data Types	Supported: NVARCHAR2(15000) NUMBER BOOLEAN (stored like NVARCHAR) TIMESTAMP(6) WITH TIME ZONE
JSON	No built-in JSON support. However, JSON strings (VARCHAR2) can be mapped into NVARCHAR2(15000) data type.
Operators	Supported: Relational: +, -, *, /, %, - (unary minus) Arithmetic: =, <>, <, >, <=, >= Logical: AND, OR, NOT Limitations: String: || (concat)
Functions and predicates	Supported: IS NULL, IS NOT NULL JAVA_REGEXP_LIKE (based on CONTAINS) ABS, CEIL/CEILING, FLOOR, ROUND EXTRACT ID LABEL, HAS_LABEL ALL_DIFFERENT IN_DEGREE, OUT_DEGREE CAST CASE IN and NOT IN Limitations: LOWER, UPPER SUBSTRING LABELS
User-defined functions	Not supported
Subqueries: Scalar subqueries EXISTS and NOT EXISTS subqueries	Supported
INSERT/UPDATE/DELETE	Supported for Oracle Database 19c and later
INTERVAL literals and operations	Not supported

The following explains a few PGQL features that require special consideration.

• Temporal Types
  
• Type Casting
  
• CONTAINS Built-in Function