mongodb 做日志服务器。
写日志最常用的方式是写入纯文本文件，然后安日期分割文件，压错旧文件。
对于程序员来说sql语句提供了丰富查询功能，相比文本文件分析更容易。
下面就是一个简单日志表, 尽量做到通用所以只有message。
create table `logging` (
`id` int(10) unsigned not null auto_increment,
`tag` enum('unknow','user','bbs','cart','admin') not null default 'unknow' comment '日志标签域',
`asctime` timestamp not null default current_timestamp comment '产生时间',
`facility` enum('unknow','account','bank','unionpay','sms','email','register') not null default 'unknow' comment '类别',
`priority` enum('info','warning','error','critical','exception','debug') not null default 'debug' comment '级别',
`message` varchar(512) not null comment '内容',
`operator` varchar(50) not null default 'computer' comment '操作者',
primary key (`id`)
)
comment='日志表'
collate='utf8_general_ci'
engine=innodb;
mongodb 的message字段比起sql更灵活
db.logging.user.save({'asctime':'2012-10-10 12:12:12','facility':'register','priority':'info','operator':'computer','message':{'name':'neo','address':{'city':'shenzhen','post':518000},'phone':[13113668890,13322993040]}})
db.logging.user.save({'asctime':'2012-10-10 12:12:12','facility':'sms','priority':'error','operator':'computer','message':'send sms: 13113668890，text: xxxxx'})
db.logging.user.find()
db.logging.admin.save({'asctime':'2012-10-10 12:12:12','facility':'account','priority':'info','operator':'computer','message':'delete account'})
db.logging.admin.save({'asctime':'2012-10-10 12:12:12','facility':'sms','priority':'info','operator':'computer','message':'send sms'})
db.logging.admin.save({'asctime':'2012-10-10 12:12:12','facility':'bank','priority':'warning','operator':'computer','message':'bank from xxxx to xxxx'})
db.logging.admin.find()
> db.logging.user.find()
{ "_id" : objectid("50cc10dd3e4f5a2b92fb5f37"), "asctime" : "2012-10-10 12:12:12", "facility" : "register", "priority" : "info", "operator" : "computer", "message" : { "name" : "neo", "address" : { "city" : "shenzhen", "post" : 518000 }, "phone" : [ 13113668890, 13322993040 ] } }
{ "_id" : objectid("50cc11a23e4f5a2b92fb5f39"), "asctime" : "2012-10-10 12:12:12", "facility" : "sms", "priority" : "error", "operator" : "computer", "message" : "send sms: 13113668890" }
> db.logging.admin.find()
{ "_id" : objectid("50cc11443e4f5a2b92fb5f38"), "asctime" : "2012-10-10 12:12:12", "facility" : "account", "priority" : "info", "operator" : "computer", "message" : "delete account" }
{ "_id" : objectid("50cc120c3e4f5a2b92fb5f3a"), "asctime" : "2012-10-10 12:12:12", "facility" : "bank", "priority" : "warning", "operator" : "computer", "message" : "bank from xxxx to xxxx" }
>