class essay extends Model { public function comment() { return $this->hasMany( App comment ) } } class comment extends Model { public function essay() { return $this->belongsTo( App essay ) } } ...
use mybatis to configure custom secondary cache. Using xml annotation can use < cache type= "com.test.dao.MybatisRedisCache " > to successfully use custom cache, but using @ CacheNamespace (implementation = MybatisRedisCache.class) on the dao i...
Table structure ...
check-in table: fields include user id userid check-in time signtime timestamp type int check-in type type is divided into 0 and 1 for check-in and check-out, respectively. A user can sign twice a day, once check-in and one check-out. Check-in and ch...
how does sql write from the database table to the display of the page? requirement: the first-level classification needs sorting, the first-level classification shows its subcategories, and the subcategories also need sorting. ...
like this SELECT * FROM material WHERE {key:value} limit 1 ...
background: 1. I am a java programmer 2. Recently interviewed for a senior development position 3. The previous project mainly used less oracle,mysql, and the companies interviewed basically used mysql s 4. I am weak in the database 5. Recently, I...
I want to optimize a sentence about group by. I don t know where to start. I want to find a train of thought . SELECT adv_id, network_id, SUM(re_click) AS clk, SUM(deny_click) AS dny_clk, SUM(re_conver) AS re_ins, SUM(mat_conver) AS mat_ins, SUM(def_...
1. Problem description assume that there are n game order tables in the database, and the table name is game_ [0-9a-z] + _ order. . It is known that there is an order number 18demo000001. How can we efficiently find out which game table this order is i...
as shown in the following figure the current time is 16 41 00. I want to take this section of data every two hours. How should sql write ? ...
do a check-in function `create_time` decimal(20,3) NOT NULL, `create_date_ymd` varchar(15) NOT NULL COMMENT , `create_date_ym` varchar(15) NOT NULL, `create_date_y` int(4) NOT NULL, `create_date_m` int(2) NOT NULL, `create_date_d` int(2) ...
subject table, which can be understood as a classification table. The course and source_book tables are associated with subject now use the subject table as the main table to query how many courses and books are under this category. query statemen...
I know that mysql master and slave have been configured, but I don t know what to do if one of them dies: 1. If there is only one master and one slave, do you want to upgrade the master manually in case the master dies? (it seems that you can t call...
for example, the isolation level of transaction An is repeatable read my understanding is that a read sql statement of transaction An is the same as the result repeated many times, regardless of whether or not other transactions have changed the data ...
Sublime installs the following plug-ins: html: ...
enter the interface with an index.vue, (first-level routing) " "( ") " ", index.vue <template> <div class="wraper"> <div class="header"> < div> <div cla...
look at the phpunit code to see how to load the configuration file of phpunit. When you call the file_exsits () function, add a backslash " " in front of it. The code is as follows: if (isset($this->arguments[ configuration ]) && ...
how to adjust Twitter to English version? https: mobile.twitter.com ...
I first generated the key through git ->sshid_rsa , ...