Reverted a couple changes by @mattwr18

We have to figure out if `mergeRels: true` is actually avoiding
duplicate relationships 🤔.

Before:
(l1)-[:IS_IN]->(l2)
(l1)-[:IS_IN]->(l3)

After:
(l1)-[:IS_IN]->(new)
(l1)-[:IS_IN]->(new)

backend/README.md

@@ -120,7 +120,7 @@ you have to migrate your data e.g. because your data modeling has changed.
 {% tab title="Docker" %}
 Generate a data migration file:
 ```bash
-$ docker-compose exec backend yarn run db:migrate:create your_data_migration --date-format 'yyyymmddHHmmss' --template-file src/db/migrate/template.js
+$ docker-compose exec backend yarn run db:migrate:create your_data_migration
 # Edit the file in ./src/db/migrations/
 ```
 
@@ -132,7 +132,7 @@ $ docker-compose exec backend yarn run db:migrate up
 {% tab title="Without Docker" %}
 Generate a data migration file:
 ```bash
-$ yarn run db:migrate:create your_data_migration --date-format 'yyyymmddHHmmss' --template-file src/db/migrate/template.js
+$ yarn run db:migrate:create your_data_migration
 # Edit the file in ./src/db/migrations/
 ```
 

backend/package.json

@@ -16,7 +16,7 @@
     "db:reset": "yarn run db:clean",
     "db:seed": "babel-node src/db/seed.js",
     "db:migrate": "yarn run __migrate --store ./src/db/migrate/store.js",
-    "db:migrate:create": "yarn run __migrate --template-file ./src/db/migrate/template.js create"
+    "db:migrate:create": "yarn run __migrate --template-file ./src/db/migrate/template.js --date-format 'yyyymmddHHmmss' create"
   },
   "author": "Human Connection gGmbH",
   "license": "MIT",

backend/src/db/migrate/store.js

@@ -35,7 +35,7 @@ class Store {
     const session = driver.session()
     const readTxResultPromise = session.readTransaction(async txc => {
       const result = await txc.run(
-        'MATCH (migration:Migration) RETURN migration {.*} ORDER BY migration.migratedAt DESC',
+        'MATCH (migration:Migration) RETURN migration {.*} ORDER BY migration.timestamp DESC',
       )
       return result.records.map(r => r.get('migration'))
     })
@@ -65,14 +65,16 @@ class Store {
     const writeTxResultPromise = session.writeTransaction(txc => {
       return Promise.all(
         migrations.map(async migration => {
-          const { title, description } = migration
+          const { title, description, timestamp } = migration
-          const properties = { title, description }
+          const properties = { title, description, timestamp }
           const migrationResult = await txc.run(
             `
               MERGE (migration:Migration { title: $properties.title })
-              ON CREATE SET migration += $properties,
+              ON MATCH SET
+              migration += $properties
+              ON CREATE SET
+              migration += $properties,
               migration.migratedAt = toString(datetime())
-              RETURN migration
             `,
             { properties },
           )

backend/src/db/migrations/20200123150110-merge_duplicate_location_nodes.js

@@ -33,7 +33,7 @@ export function up(next) {
                     ` 
                     MATCH(location:Location {id: $locationId}), (location2:Location {id: $locationId})
                     WHERE location.id = location2.id AND id(location) < id(location2)
-                    CALL apoc.refactor.mergeNodes([location, location2], { properties: 'combine' }) YIELD node as updatedLocation
+                    CALL apoc.refactor.mergeNodes([location, location2], { properties: 'combine', mergeRels: true }) YIELD node as updatedLocation
                     RETURN location {.*},updatedLocation {.*}
                   `,
                     { locationId },