Vendor-Extensions.md

@@ -51,3 +51,49 @@ paths:
           description: OK
           x-responseId: Pong
 ```
+
+### MySQL Schema
+
+#### x-mysqlSchema
+
+MySQL schema generator creates vendor extensions based on openapi `dataType` and `dataFormat`. When user defined extensions with same key already exists codegen accepts those as is. It means it won't validate properties or correct it for you. Every model in `definitions` can contain table related and column related extensions like in example below: 
+
+```yaml
+definitions:
+  Order:
+    description: This should be most common InnoDB table
+    type: object
+    properties:
+      id:
+        description: >-
+          This column should be unsigned BIGINT with AUTO_INCREMENT
+        type: integer
+        format: int64
+        x-mysqlSchema:
+          columnDefinition:
+            colName: id
+            colDataType: DECIMAL
+            colDataTypeArguments:
+              - argumentValue: 16
+                isString: false
+                hasMore: true
+              - argumentValue: 4
+                isString: false
+                hasMore: false
+            colUnsigned: true
+            colNotNull: true
+            colDefault:
+              defaultValue: AUTO_INCREMENT
+              isString: false
+              isNumeric: false
+              isKeyword: true
+            colComment: >-
+              Column comment. This column should be unsigned BIGINT with AUTO_INCREMENT
+    x-mysqlSchema:
+      tableDefinition:
+        tblName: orders
+        tblStorageEngine: InnoDB
+        tblComment: >-
+          Table comment. This should be most common InnoDB table
+```
+> :exclamation: There are properties that are not implemented by now(`tblStorageEngine`), but you can see how generator can be enhanced in future.
\ No newline at end of file