diff --git a/requirements.txt b/requirements.txt
index 2b64ee1d..ee935ce6 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,4 +1,5 @@
 PyQt5<5.12
+pyqtgraph
 dataclasses; python_version<="3.6"
 qdarkstyle
 requests
diff --git a/vnpy/trader/database.py b/vnpy/trader/database.py
index 87fb3eae..1e90dcbc 100644
--- a/vnpy/trader/database.py
+++ b/vnpy/trader/database.py
@@ -1,13 +1,47 @@
 """"""
 
-from peewee import SqliteDatabase, Model, CharField, DateTimeField, FloatField
+from peewee import CharField, DateTimeField, FloatField, Model, MySQLDatabase, PostgresqlDatabase, \
+    SqliteDatabase
 
 from .constant import Exchange, Interval
 from .object import BarData, TickData
-from .utility import get_file_path
+from .setting import SETTINGS
+from .utility import resolve_path
 
-DB_NAME = "database.db"
-DB = SqliteDatabase(str(get_file_path(DB_NAME)))
+
+def init():
+    db_settings = SETTINGS['database']
+    driver = db_settings["driver"]
+
+    init_funcs = {
+        "sqlite": init_sqlite,
+        "mysql": init_mysql,
+        "postgresql": init_postgresql,
+    }
+
+    assert driver in init_funcs
+    del db_settings['driver']
+    return init_funcs[driver](db_settings)
+
+
+def init_sqlite(settings: dict):
+    global DB
+    database = settings['database']
+
+    DB = SqliteDatabase(str(resolve_path(database)))
+
+
+def init_mysql(settings: dict):
+    global DB
+    DB = MySQLDatabase(**settings)
+
+
+def init_postgresql(settings: dict):
+    global DB
+    DB = PostgresqlDatabase(**settings)
+
+
+init()
 
 
 class DbBarData(Model):
diff --git a/vnpy/trader/engine.py b/vnpy/trader/engine.py
index af136dab..f7cf95df 100644
--- a/vnpy/trader/engine.py
+++ b/vnpy/trader/engine.py
@@ -197,7 +197,7 @@ class BaseEngine(ABC):
         pass
 
 
-class LogEngine(BaseEngine, metaclass=Singleton):
+class LogEngine(BaseEngine):
     """
     Processes log event and output with logging module.
     """
diff --git a/vnpy/trader/setting.py b/vnpy/trader/setting.py
index ae2011f9..dc82fad7 100644
--- a/vnpy/trader/setting.py
+++ b/vnpy/trader/setting.py
@@ -23,10 +23,17 @@ SETTINGS = {
     "email.receiver": "",
 
     "rqdata.username": "",
-    "rqdata.password": ""
+    "rqdata.password": "",
+    "database": {
+        "driver": "sqlite",
+        "database": "{VNPY_TEMP}/database.db",  # for sqlite, use this as filepath
+        "host": "localhost",
+        "port": 3306,
+        "user": "root",
+        "password": ""
+    }
 }
 
-
 # Load global setting from json file.
 SETTING_FILENAME = "vt_setting.json"
 SETTINGS.update(load_json(SETTING_FILENAME))
diff --git a/vnpy/trader/utility.py b/vnpy/trader/utility.py
index 6f023259..90dc6b2e 100644
--- a/vnpy/trader/utility.py
+++ b/vnpy/trader/utility.py
@@ -3,6 +3,7 @@ General utility functions.
 """
 
 import json
+import os
 from pathlib import Path
 from typing import Callable
 
@@ -31,6 +32,12 @@ class Singleton(type):
         return cls._instances[cls]
 
 
+def resolve_path(pattern: str):
+    env = dict(os.environ)
+    env.update({"VNPY_TEMP": str(TEMP_DIR)})
+    return pattern.format(**env)
+
+
 def _get_trader_dir(temp_name: str):
     """
     Get path where trader is running in.