From 3549ffc4ac867cbebf146057b4c49641db503846 Mon Sep 17 00:00:00 2001
From: eopaant <tony.opara@ericsson.com>
Date: Sun, 30 Apr 2023 13:19:35 -0500
Subject: [PATCH] add master detail relationship support

---
 packages/mermaid/src/diagrams/er/erDb.js      |  1 +
 packages/mermaid/src/diagrams/er/erMarkers.js | 26 +++++++++++++++++++
 .../mermaid/src/diagrams/er/erRenderer.js     |  6 +++++
 .../src/diagrams/er/parser/erDiagram.jison    |  2 ++
 .../src/diagrams/er/parser/erDiagram.spec.js  |  9 +++++++
 5 files changed, 44 insertions(+)

diff --git a/packages/mermaid/src/diagrams/er/erDb.js b/packages/mermaid/src/diagrams/er/erDb.js
index 5f2af0da1..2f5116cbf 100644
--- a/packages/mermaid/src/diagrams/er/erDb.js
+++ b/packages/mermaid/src/diagrams/er/erDb.js
@@ -20,6 +20,7 @@ const Cardinality = {
   ZERO_OR_MORE: 'ZERO_OR_MORE',
   ONE_OR_MORE: 'ONE_OR_MORE',
   ONLY_ONE: 'ONLY_ONE',
+  MD_PARENT: 'MD_PARENT',
 };
 
 const Identification = {
diff --git a/packages/mermaid/src/diagrams/er/erMarkers.js b/packages/mermaid/src/diagrams/er/erMarkers.js
index 948411772..48cafae65 100644
--- a/packages/mermaid/src/diagrams/er/erMarkers.js
+++ b/packages/mermaid/src/diagrams/er/erMarkers.js
@@ -7,6 +7,8 @@ const ERMarkers = {
   ONE_OR_MORE_END: 'ONE_OR_MORE_END',
   ZERO_OR_MORE_START: 'ZERO_OR_MORE_START',
   ZERO_OR_MORE_END: 'ZERO_OR_MORE_END',
+  MD_PARENT_END: 'MD_PARENT_END',
+  MD_PARENT_START: 'MD_PARENT_START',
 };
 
 /**
@@ -18,6 +20,30 @@ const ERMarkers = {
 const insertMarkers = function (elem, conf) {
   let marker;
 
+  elem
+    .append('defs')
+    .append('marker')
+    .attr('id', ERMarkers.MD_PARENT_START)
+    .attr('refX', 0)
+    .attr('refY', 7)
+    .attr('markerWidth', 190)
+    .attr('markerHeight', 240)
+    .attr('orient', 'auto')
+    .append('path')
+    .attr('d', 'M 18,7 L9,13 L1,7 L9,1 Z');
+
+  elem
+    .append('defs')
+    .append('marker')
+    .attr('id', ERMarkers.MD_PARENT_END)
+    .attr('refX', 19)
+    .attr('refY', 7)
+    .attr('markerWidth', 20)
+    .attr('markerHeight', 28)
+    .attr('orient', 'auto')
+    .append('path')
+    .attr('d', 'M 18,7 L9,13 L1,7 L9,1 Z');
+
   elem
     .append('defs')
     .append('marker')
diff --git a/packages/mermaid/src/diagrams/er/erRenderer.js b/packages/mermaid/src/diagrams/er/erRenderer.js
index 87d7ac607..93e22732a 100644
--- a/packages/mermaid/src/diagrams/er/erRenderer.js
+++ b/packages/mermaid/src/diagrams/er/erRenderer.js
@@ -478,6 +478,9 @@ const drawRelationshipFromLayout = function (svg, rel, g, insert, diagObj) {
     case diagObj.db.Cardinality.ONLY_ONE:
       svgPath.attr('marker-end', 'url(' + url + '#' + erMarkers.ERMarkers.ONLY_ONE_END + ')');
       break;
+    case diagObj.db.Cardinality.MD_PARENT:
+      svgPath.attr('marker-end', 'url(' + url + '#' + erMarkers.ERMarkers.MD_PARENT_END + ')');
+      break;
   }
 
   switch (rel.relSpec.cardB) {
@@ -502,6 +505,9 @@ const drawRelationshipFromLayout = function (svg, rel, g, insert, diagObj) {
     case diagObj.db.Cardinality.ONLY_ONE:
       svgPath.attr('marker-start', 'url(' + url + '#' + erMarkers.ERMarkers.ONLY_ONE_START + ')');
       break;
+    case diagObj.db.Cardinality.MD_PARENT:
+      svgPath.attr('marker-start', 'url(' + url + '#' + erMarkers.ERMarkers.MD_PARENT_START + ')');
+      break;
   }
 
   // Now label the relationship
diff --git a/packages/mermaid/src/diagrams/er/parser/erDiagram.jison b/packages/mermaid/src/diagrams/er/parser/erDiagram.jison
index 8ffa87c63..0c6820b49 100644
--- a/packages/mermaid/src/diagrams/er/parser/erDiagram.jison
+++ b/packages/mermaid/src/diagrams/er/parser/erDiagram.jison
@@ -57,6 +57,7 @@ accDescr\s*"{"\s*                                { this.begin("acc_descr_multili
 o\|                             return 'ZERO_OR_ONE';
 o\{                             return 'ZERO_OR_MORE';
 \|\{                            return 'ONE_OR_MORE';
+\s*u                            return 'MD_PARENT';
 \.\.                            return 'NON_IDENTIFYING';
 \-\-                            return 'IDENTIFYING';
 "to"                            return 'IDENTIFYING';
@@ -170,6 +171,7 @@ cardinality
     | 'ZERO_OR_MORE'                 { $$ = yy.Cardinality.ZERO_OR_MORE; }
     | 'ONE_OR_MORE'                  { $$ = yy.Cardinality.ONE_OR_MORE; }
     | 'ONLY_ONE'                     { $$ = yy.Cardinality.ONLY_ONE; }
+    | 'MD_PARENT'                     { $$ = yy.Cardinality.MD_PARENT; }
     ;
 
 relType
diff --git a/packages/mermaid/src/diagrams/er/parser/erDiagram.spec.js b/packages/mermaid/src/diagrams/er/parser/erDiagram.spec.js
index 904521d50..6fdc9eaa7 100644
--- a/packages/mermaid/src/diagrams/er/parser/erDiagram.spec.js
+++ b/packages/mermaid/src/diagrams/er/parser/erDiagram.spec.js
@@ -718,5 +718,14 @@ describe('when parsing ER diagram it...', function () {
       const rels = erDb.getRelationships();
       expect(rels[0].roleA).toBe('places');
     });
+
+    it('should represent parent-child relationship correctly', function () {
+      erDiagram.parser.parse('erDiagram\nPROJECT u--o{ TEAM_MEMBER : "parent"');
+      const rels = erDb.getRelationships();
+      expect(Object.keys(erDb.getEntities()).length).toBe(2);
+      expect(rels.length).toBe(1);
+      expect(rels[0].relSpec.cardB).toBe(erDb.Cardinality.MD_PARENT);
+      expect(rels[0].relSpec.cardA).toBe(erDb.Cardinality.ZERO_OR_MORE);
+    });
   });
 });