diff --git a/docs/uniCloud/cf-database.md b/docs/uniCloud/cf-database.md
index e7068237f7c785edff9a194b6c0832450b62d07f..78d9ad410cb90256d4596ad5250cada1ce004255 100644
--- a/docs/uniCloud/cf-database.md
+++ b/docs/uniCloud/cf-database.md
@@ -348,7 +348,7 @@ collection.field({ 'age': true })
 比如筛选出所有自己发表的文章，除了用传对象的方式：
 
 ```js
-const myOpenID = 'xxx'
+const myOpenID = "xxx"
 db.collection('articles').where({
   _openid: myOpenID
 })
@@ -358,7 +358,7 @@ db.collection('articles').where({
 
 ```js
 const dbCmd = db.command
-const myOpenID = 'xxx'
+const myOpenID = "xxx"
 db.collection('articles').where({
   _openid: dbCmd.eq(openid)
 })
@@ -604,25 +604,46 @@ collection.doc('doc-id').update({
 ```
 // 更新前
 {
-  _id: 'xxx',
-  name: "Hello",
-  count: {
-    fav: 0,
-    follow: 0
+  "_id": "xxx",
+  "name": "Hello",
+  "count": {
+    "fav": 0,
+    "follow": 0
   }
 }
 
 // 更新后
 {
-  _id: 'xxx',
-  name: "Hey",
-  count: {
-    fav: 1,
-    follow: 0
+  "_id": "xxx",
+  "name": "Hey",
+  "count": {
+    "fav": 1,
+    "follow": 0
   }
 }
 ```
 
+更新数组时，已数组下标作为key即可，比如以下示例将数组arr内下标为1的值修改为 uniCloud
+
+```
+collection.doc('doc-id').update({
+  arr: {
+    1: "uniCloud"
+  }
+})
+```
+
+```
+// 更新前
+{
+  "arr": ["hello", "world"]
+}
+// 更新后
+{
+  "arr": ["hello", "uniCloud"]
+}
+```
+
 ### 更新文档，如果不存在则创建
 
 collection.doc().set()
@@ -645,20 +666,20 @@ collection.doc('doc-id').set({
 ```
 // 更新前
 {
-  _id: 'xxx',
-  name: "Hello",
-  count: {
-    fav: 0,
-    follow: 0
+  "_id": "xxx",
+  "name": "Hello",
+  "count": {
+    "fav": 0,
+    "follow": 0
   }
 }
 
 // 更新后
 {
-  _id: 'xxx',
-  name: "Hey",
-  count: {
-    fav: 1
+  "_id": "xxx",
+  "name": "Hey",
+  "count": {
+    "fav": 1
   }
 }
 ```
@@ -697,21 +718,21 @@ db.collection('photo').doc('doc-id').update({
 ```
 // 更新前
 {
-  _id: 'xxx',
-  name: "Hello",
-  count: {
-    fav: 0,
-    follow: 0
+  "_id": "xxx",
+  "name": "Hello",
+  "count": {
+    "fav": 0,
+    "follow": 0
   }
 }
 
 // 更新后
 {
-  _id: 'xxx',
-  name: "Hello",
-  count: {
-    fav: 1,
-    follow: 1
+  "_id": "xxx",
+  "name": "Hello",
+  "count": {
+    "fav": 1,
+    "follow": 1
   }
 }
 ```
@@ -744,21 +765,21 @@ db.collection('user').where({
 ```
 // 更新前
 {
-  _id: 'xxx',
-  name: "Hello",
-  count: {
-    fav: 0,
-    follow: 0
+  "_id": "xxx",
+  "name": "Hello",
+  "count": {
+    "fav": 0,
+    "follow": 0
   }
 }
 
 // 更新后
 {
-  _id: 'xxx',
-  name: "Hello",
-  count: {
-    fav: 1,
-    follow: 0
+  "_id": "xxx",
+  "name": "Hello",
+  "count": {
+    "fav": 1,
+    "follow": 0
   }
 }
 ```
@@ -786,21 +807,21 @@ db.collection('user').where({
 ```
 // 更新前
 {
-  _id: 'xxx',
-  name: "Hello",
-  count: {
-    fav: 2,
-    follow: 0
+  "_id": "xxx",
+  "name": "Hello",
+  "count": {
+    "fav": 2,
+    "follow": 0
   }
 }
 
 // 更新后
 {
-  _id: 'xxx',
-  name: "Hello",
-  count: {
-    fav: 20,
-    follow: 0
+  "_id": "xxx",
+  "name": "Hello",
+  "count": {
+    "fav": 20,
+    "follow": 0
   }
 }
 ```
@@ -822,15 +843,15 @@ db.collection('comments').doc('comment-id').update({
 ```
 // 更新前
 {
-  _id: 'xxx',
-  rating: 5,
-  comment: 'xxxx'
+  "_id": "xxx",
+  "rating": 5,
+  "comment": "xxx"
 }
 
 // 更新后
 {
-  _id: 'xxx',
-  comment: 'xxxx'
+  "_id": "xxx",
+  "comment": "xxx"
 }
 ```
 
@@ -852,14 +873,14 @@ db.collection('comments').doc('comment-id').update({
 ```
 // 更新前
 {
-  _id: 'xxx',
-  users: ['a','b']
+  "_id": "xxx",
+  "users": ["a","b"]
 }
 
 // 更新后
 {
-  _id: 'xxx',
-  users: ['a','b','c','d']
+  "_id": "xxx",
+  "users": ["a","b","c","d"]
 }
 ```
 
@@ -879,14 +900,14 @@ db.collection('comments').doc('comment-id').update({
 ```
 // 更新前
 {
-  _id: 'xxx',
-  users: ['a','b']
+  "_id": "xxx",
+  "users": ["a","b"]
 }
 
 // 更新后
 {
-  _id: 'xxx',
-  users: ['a']
+  "_id": "xxx",
+  "users": ["a"]
 }
 ```
 
@@ -908,14 +929,14 @@ db.collection('comments').doc('comment-id').update({
 ```
 // 更新前
 {
-  _id: 'xxx',
-  users: ['a','b']
+  "_id": "xxx",
+  "users": ["a","b"]
 }
 
 // 更新后
 {
-  _id: 'xxx',
-  users: ['c','d','a','b']
+  "_id": "xxx",
+  "users": ["c","d","a","b"]
 }
 ```
 
@@ -935,14 +956,14 @@ db.collection('comments').doc('comment-id').update({
 ```
 // 更新前
 {
-  _id: 'xxx',
-  users: ['a','b']
+  "_id": "xxx",
+  "users": ["a","b"]
 }
 
 // 更新后
 {
-  _id: 'xxx',
-  users: ['b']
+  "_id": "xxx",
+  "users": ["b"]
 }
 ```