Collection for Schema relations

Closes: #327

PR-URL: #347

CHANGELOG.md

@@ -3,6 +3,7 @@
 ## [Unreleased][unreleased]
 
 - Schema projection
+- Schema.prototype.relations: Set<{ to: string, type: string }>
 
 ## [1.3.1][] - 2021-06-26
 

lib/schema.js

@@ -134,6 +134,7 @@ class Schema {
     this.fields = {};
     this.indexes = {};
     this.references = new Set();
+    this.relations = new Set();
     this.validate = defs.validate || null;
     this.format = defs.format || null;
     this.parse = defs.parse || null;
@@ -172,6 +173,7 @@ class Schema {
           const schema = Schema.from(entry);
           this.fields[key] = schema;
           this.references = new Set([...this.references, ...schema.references]);
+          this.relations = new Set([...this.relations, ...schema.relations]);
         }
         continue;
       }
@@ -184,6 +186,9 @@ class Schema {
       if (!Reflect.has(def, 'required')) def.required = required;
       if (def.length) def.length = formatLength(def.length);
       this.references.add(type);
+      if (isFirstUpper(type)) {
+        this.relations.add({ to: type, type: 'many-to-one' });
+      }
       this.fields[key] = def;
     }
   }
@@ -192,7 +197,10 @@ class Schema {
     const { index, primary, unique, many } = def;
     const isIndex = many || Array.isArray(index || primary || unique);
     if (isIndex) this.indexes[key] = def;
-    if (many) this.references.add(many);
+    if (many) {
+      this.references.add(many);
+      this.relations.add({ to: many, type: 'one-to-many' });
+    }
     return isIndex;
   }
 

test/database.js

@@ -46,6 +46,7 @@ metatests.test('Schema: database', (test) => {
         },
         indexes: {},
         references: new Set(['Country']),
+        relations: new Set([]),
         validate: null,
         format: null,
         parse: null,
@@ -58,6 +59,7 @@ metatests.test('Schema: database', (test) => {
       altKey: { unique: ['name', 'street'] },
     },
     references: new Set(['Country', 'Person']),
+    relations: new Set([]),
     validate: null,
     format: null,
     parse: null,

test/model.js

@@ -57,6 +57,7 @@ metatests.test('Model: from struct', (test) => {
     fields: { name: { type: 'string', unique: true, required: true } },
     indexes: { addresses: { many: 'Address' } },
     references: new Set(['Address']),
+    relations: new Set([]),
     validate: null,
     format: null,
     parse: null,

types/metaschema.d.ts

@@ -13,6 +13,17 @@ type Kind =
   | 'struct'
   | 'scalar';
 
+type Cardinality =
+  | 'one-to-one'
+  | 'one-to-many'
+  | 'many-to-one'
+  | 'many-to-many';
+
+interface Relation {
+  to: string;
+  type: Cardinality;
+}
+
 export class Schema {
   name: string;
   namespaces: Set<Model>;
@@ -22,6 +33,7 @@ export class Schema {
   fields: object;
   indexes: object;
   references: Set<string>;
+  relations: Set<Relation>;
   validate: Function | null;
   format: Function | null;
   parse: Function | null;