Sqlite创建自增字段，代码如下：
CREATE TABLE [push_widget] (
[_id] INTEGER PRIMARY KEY AUTOINCREMENT,
[push_id] VARCHAR(50) NOT NULL,
[type] INT(10) NOT NULL DEFAULT (0),
[url] VARCHAR,
[pic_url] VARCHAR,
[short] VARCHAR,
[author] CHAR,
[push_type] INT NOT NULL DEFAULT (0),
[time] TIMESTAMP,
[score] FLOAT DEFAULT (0));