Update README.md

Author: ralgond

README.md

@@ -11,6 +11,7 @@ A python ORM like mybatis.
 pip install -U mybatis
 
 ### Create Database
+#### mysql
 ```sql
 CREATE DATABASE mybatis;
 
@@ -20,10 +21,22 @@ CREATE TABLE IF NOT EXISTS fruits (
         id INT AUTO_INCREMENT PRIMARY KEY, 
         name VARCHAR(100),
         category VARCHAR(100),
-        price int)
+        price int);
 
-INSERT INTO fruits (name, category, price) VALUES ('Alice', 'A', 100)
-INSERT INTO fruits (name, category, price) VALUES ('Bob', 'B', 200)
+INSERT INTO fruits (name, category, price) VALUES ('Alice', 'A', 100);
+INSERT INTO fruits (name, category, price) VALUES ('Bob', 'B', 200);
+```
+#### postgresql
+```sql
+CREATE TABLE if not exists fruits (
+        id SERIAL PRIMARY KEY, 
+        name VARCHAR(100),
+        category VARCHAR(100),
+        price int);
+        
+INSERT INTO fruits (name, category, price) VALUES ('Alice', 'A', 100);
+
+INSERT INTO fruits (name, category, price) VALUES ('Bob', 'B', 200);
 ```
 
 ### Write Code
@@ -35,6 +48,9 @@ Create a mapper directory, and create a file named mapper/test.xml, as follows:
 <?xml version="1.0" encoding="UTF-8"?>
 <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
 <mapper>
+    <insert id="testInsert1", primary_key="id">
+        INSERT INTO fruits (name, category, price) VALUES (#{name}, #{category}, #{price})
+    </insert>
     <select id="testBasic1">
         SELECT * from fruits where id=#{id}
     </select>
@@ -43,18 +59,18 @@ Create a mapper directory, and create a file named mapper/test.xml, as follows:
 Create a Python file named "test.py" as follows:
 ```python
 from mybatis import *
-import mysql.connector
 
 def main():
-    conn = mysql.connector.connect(
-        host="localhost",
-        user="mybatis",
-        password="mybatis",
-        database="mybatis"
-    )
+    conn = ConnectionFactory.get_connection(
+            dbms_name='mysql', # change to 'postgresql' if you are using PostgreSQL
+            host="localhost",
+            user="mybatis",
+            password="mybatis",
+            database="mybatis")
 
     mb = Mybatis(conn, "mapper", cache_memory_limit=50*1024*1024)
 
+    ret = mb.insert('testInsert1', {'name':'Alice', 'category':'C', 'price':500}
     ret = mb.select_one("testBasic1", {'id':1})
 
     print(ret)
@@ -66,15 +82,14 @@ if __name__ == "__main__":
 ## Decorator
 The example is as follows:
 ```python
-import mysql.connector
-from mybatis import Mybatis
+from mybatis import Mybatis, ConnectionFactory
 
-conn = mysql.connector.connect(
+conn = ConnectionFactory.get_connection(
+    dbms_name='mysql', # change to 'postgresql' if you are using PostgreSQL
     host="localhost",
     user="mybatis",
     password="mybatis",
-    database="mybatis"
-)
+    database="mybatis")
 
 mb = Mybatis(conn, "mapper", cache_memory_limit=50*1024*1024)
 
@@ -86,7 +101,7 @@ def get_one(id:int):
 def get_many():
     pass
 
-@mb.Insert("INSERT INTO fruits (name, category, price) VALUES (#{name}, #{category}, #{price})")
+@mb.Insert("INSERT INTO fruits (name, category, price) VALUES (#{name}, #{category}, #{price})", primary_key="id")
 def insert(name:str, category:str, price:int):
     pass
 
@@ -123,6 +138,9 @@ Create xml mapper as follows:
 <mapper namespace="test_namespace">
     <insert id="testInsert">
         INSERT INTO fruits (name, category, price) VALUES (#{name},#{category},#{price})
+        <if test="'__need_returning_id__' in params">
+            RETURNING id
+        </if>
     </insert>
     <delete id="testDelete">
         DELETE FROM fruits WHERE id=#{id}
@@ -179,22 +197,21 @@ Based on security considerations, in order to prevent SQL injection, it is recom
 mybatis-py maintains a cache pool for each connection. The elimination strategy is LRU. You can define the maximum byte capacity of the pool. If you do not want to use cache, you can set the parameter configuration. The code is as follows:
 ```python
 from mybatis import *
-import mysql.connector
 
 def main():
-    conn1 = mysql.connector.connect(
-        host="localhost",
-        user="mybatis",
-        password="mybatis",
-        database="mybatis"
-    )
-
-    conn2 = mysql.connector.connect(
-        host="localhost",
-        user="mybatis",
-        password="mybatis",
-        database="mybatis"
-    )
+    conn1 = ConnectionFactory.get_connection(
+            dbms_name='mysql', # change to 'postgresql' if you are using PostgreSQL
+            host="localhost",
+            user="mybatis",
+            password="mybatis",
+            database="mybatis")
+
+    conn2 = ConnectionFactory.get_connection(
+            dbms_name='mysql', # change to 'postgresql' if you are using PostgreSQL
+            host="localhost",
+            user="mybatis",
+            password="mybatis",
+            database="mybatis")
 
     mb1 = Mybatis(conn1, "mapper", cache_memory_limit=50*1024*1024) # Capacity limit is 50MB
     mb2 = Mybatis(conn2, "mapper", cache_memory_limit=None) # Disable caching