INTERNATIONAL ISO/IEC STANDARD 9075-16 First edition 2023-06 Information technology Database languages SQL - Part 16: Property Graph Queries (SQL/PGQ) Reference number IEC IS0/IEC 9075-16:2023(E) OS1 @ IS0/IEC 2023 IS0/IEC 9075-16:2023(E) COPYRIGHT PROTECTED DOCUMENT @IS0/IEC2023 All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on or ISo's member body in the country of the requester. ISO copyright office CP 401 · Ch. de Blandonnet 8 CH-1214 Vernier, Geneva Phone: +41 22 749 01 11 Email: [email protected] Website: www.iso.org Published in Switzerland i @ IS0/IEC 2023 - All rights reserved IS0/IEC 9075-16:2023(E) Contents Page Foreword. . viii Introduction. 1 Scope. 2 Normative references. 2 3 Terms and definitions. 4 Concepts. 8 4.1 Notations and conventions. . 4.1.1 Notations. 4.2 Columns, fields, and attributes. 4.3 SQL-statements. . 4.3.1 SQL-statements classified by function. 4.3.1.1 SQL-schema statements. 4.4 Basic security model. . 4.4.1 Privileges. 4.5 SQL-property graphs. 4.5.1 Introduction to SQL-property graphs. 4.5.2 Pure property graph. 4.5.3 Tabular property graph.. 4.6 Operations involving property graphs. 4.7 Graph pattern matching. . . 13 4.7.1 Summary of graph pattern matching. 13 4.7.2 Paths.. 4.7.3 Path patterns. 4.7.4 Graph pattern variables. 4.7.5 References to graph pattern variables. 16 4.7.6 Path pattern matching. .. 17 4.7.7 Path modes... 18 4.7.8 Selective path search prefixes. 19 4.7.9 Match modes.. 5 Lexical elements. . ... 5.1 <SQL terminal character> 5.2 <token> and <separator>. 5.3 Names and identifiers. .24 6 Scalar expressions. .26 6.1 <value expression primary>. .26 6.2 <identifier chain>. .28 6.3 <set function specification> .30 6.4 <case expression> .32 @ IS0/IEC 2023 - All rights reserved iii IS0/IEC 9075-16:2023(E) 6.5 <property reference>. .33 6.6 <element_id function>. .35 6.7 <graphical match number function>. 6.8 <graphical path name function>. 6.9 <graphical element number function>. 6.10 <graphical path length function>. . 7 Query expressions. 7.1 <tablereference>. 7.2 <query specification>. ..50 8 Predicates. ..51 8.1 <predicate>. .51 8.2 <directed predicate>. . .52 8.3 <labeled predicate>. . .53 8.4 <source/destination predicate>. 54 8.5 <all_different predicate>. . .56 8.6 <same predicate>.. . .57 8.7 <bound predicate>. . 8.8 <property_exists predicate>. 9 Additional common rules..... 9.1 Potential sources of non-determinism. 9.2 Contextual inference of a set of labels. ..62 9.3 Expansion of an <all properties reference> ..65 9.4 Satisfaction of a <label expression> by a defined label set. .67 9.5 Converting a tabular property graph to a pure property graph. .69 9.6 Machinery for graph pattern matching. .72 9.7 Evaluation of a <path pattern expression>. 9.8 Evaluation of a selective <path pattern>. .82 9.9 Applying bindings to evaluate an expression. .86 9.10 Applying bindings to evaluate a subexpression of an aggregate. .89 9.11 Applying bindings to generate a row. . 91 9.12 Creation of an element table descriptor. . 94 9.13 Creation of a vertex table descriptor. . .98 9.14 Creation of an edge table descriptor. . .99 9.15 Consistency check of a tabular property graph descriptor. ..102 9.16 Deriving a pure property graph descriptor from a tabular property graph descriptor. . . 10 Additional common elements. 10.1 <aggregate function>. 10.2 <sort specification list>. 10.3 <graph reference>. .109 10.4 <graph pattern>. . .110 10.5 <path pattern prefix>. .116 10.6 <path pattern expression>. .120 10.7 <graph pattern quantifier>. .129 10.8 <label expression>. .131 10.9 <simplified path pattern expression>. . 133 10.10 <element reference>. 138 iv @ IS0/IEC 2023 - All rights reserved IS0/IEC 9075-16:2023(E) 10.11 <path reference>. 140 11 Schema definition and manipulat