From c575a4e71922f7eb1c892e12eb23a0cab4adccd2 Mon Sep 17 00:00:00 2001
From: ruozhixian <ruozhixian@sina.com>
Date: Thu, 11 Mar 2021 16:36:49 +0800
Subject: [PATCH] support to preload all children in multiple levels
 associations

---
 callbacks/query.go | 24 +++++++++++++++++++-----
 1 file changed, 19 insertions(+), 5 deletions(-)

diff --git a/callbacks/query.go b/callbacks/query.go
index 1868c247..df5b4d60 100644
--- a/callbacks/query.go
+++ b/callbacks/query.go
@@ -185,12 +185,26 @@ func Preload(db *gorm.DB) {
 				}
 			} else {
 				preloadFields := strings.Split(name, ".")
-				if _, ok := preloadMap[preloadFields[0]]; !ok {
-					preloadMap[preloadFields[0]] = map[string][]interface{}{}
-				}
+				if preloadFields[0] == clause.Associations {
+					for _, rel := range db.Statement.Schema.Relationships.Relations {
+						if rel.Schema == db.Statement.Schema {
+							if _, ok := preloadMap[rel.Name]; !ok {
+								preloadMap[rel.Name] = map[string][]interface{}{}
+							}
 
-				if value := strings.TrimPrefix(strings.TrimPrefix(name, preloadFields[0]), "."); value != "" {
-					preloadMap[preloadFields[0]][value] = db.Statement.Preloads[name]
+							if value := strings.TrimPrefix(strings.TrimPrefix(name, preloadFields[0]), "."); value != "" {
+								preloadMap[rel.Name][value] = db.Statement.Preloads[name]
+							}
+						}
+					}
+				} else {
+					if _, ok := preloadMap[preloadFields[0]]; !ok {
+						preloadMap[preloadFields[0]] = map[string][]interface{}{}
+					}
+
+					if value := strings.TrimPrefix(strings.TrimPrefix(name, preloadFields[0]), "."); value != "" {
+						preloadMap[preloadFields[0]][value] = db.Statement.Preloads[name]
+					}
 				}
 			}
 		}