add length option to nanoid (#6508)

* add length option to nanoid

* add length option to nanoid

* Update content/200-orm/500-reference/100-prisma-schema-reference.mdx

content/200-orm/500-reference/100-prisma-schema-reference.mdx

@@ -3150,7 +3150,7 @@ model User {
 
 ### `nanoid()`
 
-Generated values based on the [Nano ID](https://github.com/ai/nanoid) spec.
+Generated values based on the [Nano ID](https://github.com/ai/nanoid) spec. `nanoid()` accepts an integer value between 2 and 255 that specifies the _length_ of the generate ID value, e.g. `nanoid(16)` will generated ID with 16 characters. If you don't provide a value to the nanoid() function, the default value is 21.
 
 :::info
 
@@ -3173,7 +3173,7 @@ There are two main differences between Nano ID and UUID v4:
 
 #### Examples
 
-##### Generate `nanoid()` values as IDs
+##### Generate `nanoid()` values with 21 characters as IDs
 
 <TabbedContent code>
 <TabItem value="Relational databases">
@@ -3198,6 +3198,32 @@ model User {
 </TabItem>
 </TabbedContent>
 
+##### Generate `nanoid()` values with 16 characters as IDs
+
+<TabbedContent code>
+<TabItem value="Relational databases">
+
+```prisma
+model User {
+  id   String @id @default(nanoid(16))
+  name String
+}
+```
+
+</TabItem>
+<TabItem value="MongoDB">
+
+```prisma
+model User {
+  id   String @id @default(nanoid(16)) @map("_id")
+  name String
+}
+```
+
+</TabItem>
+</TabbedContent>
+
+
 
 
 ### `now()`