魏长东

weichangdong

lua学习之操作mysql

Mysql客户端

lua-resty-mysql是为基于cosocket API的ngx_lua提供的Lua Mysql客户端,通过它可以完成Mysql的操作。默认安装OpenResty时已经自带了该模块。

local function close_db(db)  
    if not db then  
        return  
    end  
    db:close()  
end  
  
local mysql = require("resty.mysql")  
--创建实例  
local db, err = mysql:new()  
if not db then  
    ngx.say("new mysql error : ", err)  
    return  
end  
--设置超时时间(毫秒)  
db:set_timeout(1000)  
  
local props = {  
    host = "127.0.0.1",  
    port = 3306,  
    database = "mysql",  
    user = "root",  
    password = "123456"  
}  
  
local res, err, errno, sqlstate = db:connect(props)  
  
if not res then  
   ngx.say("connect to mysql error : ", err, " , errno : ", errno, " , sqlstate : ", sqlstate)  
   return close_db(db)  
end  
  
--删除表  
local drop_table_sql = "drop table if exists test"  
res, err, errno, sqlstate = db:query(drop_table_sql)  
if not res then  
   ngx.say("drop table error : ", err, " , errno : ", errno, " , sqlstate : ", sqlstate)  
   return close_db(db)  
end  
  
--创建表  
local create_table_sql = "create table test(id int primary key auto_increment, ch varchar(100))"  
res, err, errno, sqlstate = db:query(create_table_sql)  
if not res then  
   ngx.say("create table error : ", err, " , errno : ", errno, " , sqlstate : ", sqlstate)  
   return close_db(db)  
end  
  
--插入  
local insert_sql = "insert into test (ch) values('hello')"  
res, err, errno, sqlstate = db:query(insert_sql)  
if not res then  
   ngx.say("insert error : ", err, " , errno : ", errno, " , sqlstate : ", sqlstate)  
   return close_db(db)  
end  
  
res, err, errno, sqlstate = db:query(insert_sql)  
  
ngx.say("insert rows : ", res.affected_rows, " , id : ", res.insert_id, "<br/>")  
  
--更新  
local update_sql = "update test set ch = 'hello2' where id =" .. res.insert_id  
res, err, errno, sqlstate = db:query(update_sql)  
if not res then  
   ngx.say("update error : ", err, " , errno : ", errno, " , sqlstate : ", sqlstate)  
   return close_db(db)  
end  
  
ngx.say("update rows : ", res.affected_rows, "<br/>")  
--查询  
local select_sql = "select id, ch from test"  
res, err, errno, sqlstate = db:query(select_sql)  
if not res then  
   ngx.say("select error : ", err, " , errno : ", errno, " , sqlstate : ", sqlstate)  
   return close_db(db)  
end  
  
  
for i, row in ipairs(res) do  
   for name, value in pairs(row) do  
     ngx.say("select row ", i, " : ", name, " = ", value, "<br/>")  
   end  
end  
  
ngx.say("<br/>")  
--防止sql注入  
local ch_param = ngx.req.get_uri_args()["ch"] or ''  
--使用ngx.quote_sql_str防止sql注入  
local query_sql = "select id, ch from test where ch = " .. ngx.quote_sql_str(ch_param)  
res, err, errno, sqlstate = db:query(query_sql)  
if not res then  
   ngx.say("select error : ", err, " , errno : ", errno, " , sqlstate : ", sqlstate)  
   return close_db(db)  
end  
  
for i, row in ipairs(res) do  
   for name, value in pairs(row) do  
     ngx.say("select row ", i, " : ", name, " = ", value, "<br/>")  
   end  
end  
  
--删除  
local delete_sql = "delete from test"  
res, err, errno, sqlstate = db:query(delete_sql)  
if not res then  
   ngx.say("delete error : ", err, " , errno : ", errno, " , sqlstate : ", sqlstate)  
   return close_db(db)  
end  
  
ngx.say("delete rows : ", res.affected_rows, "<br/>")  
  
  
close_db(db)  

对于新增/修改/删除会返回如下格式的响应:

{  
    insert_id = 0,  
    server_status = 2,  
    warning_count = 1,  
    affected_rows = 32,  
    message = nil  
}  

affected_rows表示操作影响的行数,insert_id是在使用自增序列时产生的id。

 

对于查询会返回如下格式的响应:

{  
    { id= 1, ch= "hello"},  
    { id= 2, ch= "hello2"}  
}  

其他如MongoDB等数据库的客户端可以从github上查找使用。