用来获取JavaScript数据类型[[Class]]的对象 <!DOCTYPE html> <html> <head> <script src="http://code.jquery.com/jquery-latest.js"></script> </head> <body> Is it a RegExp? <b></b> <script>$("b&quo
function type(obj){ return Object.prototype.toString.call(obj).slice(8,-1); } var t=type(new Number(1)); console.log(t); var t=type("abc"); console.log(t); var t=type(new String("abc")); console.log(t); var t=type(true); console.log(t
在MySQL中,NULL字段的处理,需要注意,当在处理查询条件中有NULL,很有可能你得到的值不是想要的,因为,在MySQL中,判断NULL值相等(=)或者不等(!=)都会返回false.主要出现在常见的SELECT以及WHERE字句中. 为了处理这种特殊的情况,MySQL提供了如下的关键字进行特殊处理: IS NULL: 当列的值是NULL,此运算符返回true. IS NOT NULL: 当列的值不为NULL, 运算符返回true. <=>: 比较操作符(不同于=运算符),当比较的的两个值
mysql> create table test( sn int, -> `createdTime` datetime NOT NULL COMMENT '创建时间', -> `updatedTime` datetime DEFAULT NULL); ERROR 2006 (HY000): MySQL server has gone away No connection. Trying to reconnect... Connection id: 1199508 Current data
For MyISAM tables, MySQL can create spatial indexes using syntax similar to that for creating regular indexes, but extended with the SPATIAL keyword. Currently, columns in spatial indexes must be declared NOT NULL. The following examples demonstrate
版本:.NET Framework 3.5 先来一个反射调用方法的例子: using System; using System.Reflection; class Example { static void Main() { Type t = typeof(String); MethodInfo substr = t.GetMethod("Substring", new Type[] { typeof(int), typeof(int) }); // 用MethodBase类的Invo
