improve monitor-client support

src/main/java/com/alibaba/druid/support/monitor/annotation/AggregateType.java

@@ -0,0 +1,23 @@
+/*
+ * Copyright 1999-2011 Alibaba Group Holding Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.alibaba.druid.support.monitor.annotation;
+
+public enum AggregateType {
+    None, //
+    Sum, //
+    Max, //
+    Last
+}

src/main/resources/support/monitor/mysql/const.sql

@@ -0,0 +1,10 @@
+CREATE TABLE druid_const (
+	id bigint(20) AUTO_INCREMENT NOT NULL,  
+	domain varchar(45) NOT NULL, 
+	app varchar(45) NOT NULL, 
+	type varchar(45) NOT NULL,
+	hash bigint(20) NOT NULL,
+	value text,
+	PRIMARY KEY (id),
+	UNIQUE (domain, app, type, hash)
+)