Fix for many to many relationships where the union table has arbituarily named foreign key constraint columns, an example has been provided in the scripts directory.

packages/builder/src/pages/builder/app/[application]/data/datasource/[selectedDatasource]/CreateEditRelationship/CreateEditRelationship.svelte

@@ -156,6 +156,8 @@
         ...relateTo,
         through: through._id,
         fieldName: fromTable.primary[0],
+        throughFrom: relateFrom.throughTo,
+        throughTo: relateFrom.throughFrom,
       }
     } else {
       // the relateFrom.fieldName should remain the same, as it is the foreignKey in the other
@@ -251,6 +253,22 @@
       bind:error={errors.through}
       bind:value={fromRelationship.through}
     />
+    {#if fromTable && toTable && through}
+      <Select
+        label={`Foreign Key (${fromTable?.name})`}
+        options={Object.keys(through?.schema)}
+        on:change={() => ($touched.fromForeign = true)}
+        bind:error={errors.fromForeign}
+        bind:value={fromRelationship.throughTo}
+      />
+      <Select
+        label={`Foreign Key (${toTable?.name})`}
+        options={Object.keys(through?.schema)}
+        on:change={() => ($touched.toForeign = true)}
+        bind:error={errors.toForeign}
+        bind:value={fromRelationship.throughFrom}
+      />
+    {/if}
   {:else if fromRelationship?.relationshipType && toTable}
     <Select
       label={`Foreign Key (${toTable?.name})`}

packages/server/scripts/integrations/customer-categories/docker-compose.yml

@@ -0,0 +1,28 @@
+version: "3.8"
+services:
+  db:
+    container_name: postgres
+    image: postgres
+    restart: always
+    environment:
+      POSTGRES_USER: root
+      POSTGRES_PASSWORD: root
+      POSTGRES_DB: main
+    ports:
+      - "5432:5432"
+    volumes:
+      #- pg_data:/var/lib/postgresql/data/
+      - ./init.sql:/docker-entrypoint-initdb.d/init.sql
+
+  pgadmin:
+    container_name: pgadmin-pg
+    image: dpage/pgadmin4
+    restart: always
+    environment:
+      PGADMIN_DEFAULT_EMAIL: root@root.com
+      PGADMIN_DEFAULT_PASSWORD: root
+    ports:
+      - "5050:80"
+
+#volumes:
+#  pg_data:

packages/server/scripts/integrations/customer-categories/init.sql

@@ -0,0 +1,41 @@
+SELECT 'CREATE DATABASE main'
+WHERE NOT EXISTS (SELECT FROM pg_database WHERE datname = 'main')\gexec
+
+CREATE TABLE categories
+(
+    name text COLLATE pg_catalog."default",
+    id integer NOT NULL GENERATED ALWAYS AS IDENTITY ( INCREMENT 1 START 1 MINVALUE 1 MAXVALUE 2147483647 CACHE 1 ),
+    CONSTRAINT categories_pkey PRIMARY KEY (id)
+);
+
+CREATE TABLE customers
+(
+    id integer NOT NULL GENERATED ALWAYS AS IDENTITY ( INCREMENT 1 START 1 MINVALUE 1 MAXVALUE 2147483647 CACHE 1 ),
+    name text COLLATE pg_catalog."default",
+    email text COLLATE pg_catalog."default",
+    age integer,
+    "dateOfBirth" date,
+    CONSTRAINT customers_pkey PRIMARY KEY (id)
+);
+
+CREATE TABLE customer_category
+(
+    customer_id integer,
+    category_id integer,
+    notes text COLLATE pg_catalog."default",
+    id integer NOT NULL GENERATED ALWAYS AS IDENTITY ( INCREMENT 1 START 1 MINVALUE 1 MAXVALUE 2147483647 CACHE 1 ),
+    CONSTRAINT "Category" FOREIGN KEY (category_id)
+        REFERENCES public.categories (id) MATCH SIMPLE
+        ON UPDATE NO ACTION
+        ON DELETE NO ACTION
+        NOT VALID,
+    CONSTRAINT "Customer" FOREIGN KEY (customer_id)
+        REFERENCES public.customers (id) MATCH SIMPLE
+        ON UPDATE NO ACTION
+        ON DELETE NO ACTION
+        NOT VALID
+);
+
+
+INSERT INTO customers (name, email, age) VALUES ('Mike', 'mike@mike.com', 30);
+INSERT INTO categories (name) VALUES ('Books');

packages/server/scripts/integrations/customer-categories/reset.sh

@@ -0,0 +1,3 @@
+#!/bin/bash
+docker-compose down
+docker volume prune -f

packages/server/src/api/controllers/row/ExternalRequest.ts

@@ -205,9 +205,9 @@ module External {
         } else {
           // we're not inserting a doc, will be a bunch of update calls
           const isUpdate = !field.through
-          const thisKey: string = isUpdate ? "id" : linkTablePrimary
+          const thisKey: string = isUpdate ? "id" : (field.throughTo || linkTablePrimary)
           // @ts-ignore
-          const otherKey: string = isUpdate ? field.fieldName : tablePrimary
+          const otherKey: string = isUpdate ? field.fieldName : (field.throughFrom || tablePrimary)
           row[key].map((relationship: any) => {
             // we don't really support composite keys for relationships, this is why [0] is used
             manyRelationships.push({
@@ -328,12 +328,11 @@ module External {
         if (!table.primary || !linkTable.primary) {
           continue
         }
-        const definition = {
+        const definition: any = {
           // if no foreign key specified then use the name of the field in other table
           from: field.foreignKey || table.primary[0],
           to: field.fieldName,
           tableName: linkTableName,
-          through: undefined,
           // need to specify where to put this back into
           column: fieldName,
         }
@@ -343,8 +342,10 @@ module External {
           )
           definition.through = throughTableName
           // don't support composite keys for relationships
-          definition.from = table.primary[0]
-          definition.to = linkTable.primary[0]
+          definition.from = field.throughFrom || table.primary[0]
+          definition.to = field.throughTo || linkTable.primary[0]
+          definition.fromPrimary = table.primary[0]
+          definition.toPrimary = linkTable.primary[0]
         }
         relationships.push(definition)
       }
@@ -369,7 +370,8 @@ module External {
         }
         const isMany = field.relationshipType === RelationshipTypes.MANY_TO_MANY
         const tableId = isMany ? field.through : field.tableId
-        const fieldName = isMany ? primaryKey : field.fieldName
+        const manyKey = field.throughFrom || primaryKey
+        const fieldName = isMany ? manyKey : field.fieldName
         const response = await makeExternalQuery(this.appId, {
           endpoint: getEndpoint(tableId, DataSourceOperation.READ),
           filters: {

packages/server/src/definitions/common.ts

@@ -15,6 +15,8 @@ export interface FieldSchema {
   through?: string
   foreignKey?: string
   autocolumn?: boolean
+  throughFrom?: string
+  throughTo?: string
   constraints?: {
     type?: string
     email?: boolean

packages/server/src/definitions/datasource.ts

@@ -121,6 +121,8 @@ export interface RelationshipsJson {
   through?: string
   from?: string
   to?: string
+  fromPrimary?: string
+  toPrimary?: string
   tableName: string
   column: string
 }

packages/server/src/integrations/base/sql.ts

@@ -112,14 +112,16 @@ function addRelationships(
       )
     } else {
       const throughTable = relationship.through
+      const fromPrimary = relationship.fromPrimary
+      const toPrimary = relationship.toPrimary
       query = query
         // @ts-ignore
         .leftJoin(
           throughTable,
-          `${fromTable}.${from}`,
+          `${fromTable}.${fromPrimary}`,
           `${throughTable}.${from}`
         )
-        .leftJoin(toTable, `${toTable}.${to}`, `${throughTable}.${to}`)
+        .leftJoin(toTable, `${toTable}.${toPrimary}`, `${throughTable}.${to}`)
     }
   }
   return query