下面介绍异步数据库与同步数据库操作的错误和异常。
(1) 异步数据库操作抛出的异常使用 SQLError 对象表示，由 SQLError 接口定义，代码如下：
interface SQLError {
const unsigned short UNKNOWN_ERR = 0;
const unsigned short DATABASE_ERR = 1;
const unsigned short VERSION_ERR = 2;
const unsigned short TOO_LARGE_ERR = 3;
const unsigned short QUOTA_ERR = 4;
const unsigned short SYNTAX_ERR = 5;
const unsigned short CONSTRAINT_ERR = 6;
const unsigned short TIMEOUT_ERR = 7;
readonly attribute unsigned short code;
readonly attribute DOMString message;
};
属性 code 返回出错代码，值与常量的值一一对应；属性 message 返回出错消息提示。
同步数据库操作抛出的异常使用 SQLException 对象表示，由 SQLException 接口定义，代码如下：
interface SQLException {
const unsigned short UNKNOWN_ERR = 0;
const unsigned short DATABASE_ERR = 1;
const unsigned short VERSION_ERR = 2;
const unsigned short TOO_LARGE_ERR = 3;
const unsigned short QUOTA_ERR = 4;
const unsigned short SYNTAX_ERR = 5;
const unsigned short CONSTRAINT_ERR = 6;
const unsigned short TIMEOUT_ERR = 7;
unsigned short code;
DOMString message;
};
属性 code 返回出错代码，值与常量的值一一对应；属性 message 返回出错消息提示。