update:完善数据库和Kafka相关结构

dao/db/example.py

@@ -0,0 +1,23 @@
+from dao.db.util import get_connet
+
+def exmaple_query():
+    with get_connet() as conn:
+        cursor = conn.cursor()
+        cursor.execute("select * from user")
+        for row in cursor.fetchall():
+            print(row)
+        cursor.close()
+
+def exmaple_insert():
+    with get_connet() as conn:
+        with conn.cursor() as cursor:
+            cursor.execute("insert into user(name, age) values('test', 18)")
+            conn.commit()
+            cursor.close()
+
+def exmaple_update():
+    with get_connet() as conn:
+        with conn.cursor() as cursor:
+            cursor.execute("update user set age=19 where name='test'")
+            conn.commit()
+            cursor.close()