• MySQL learning


    1. Throughput definition: the number of queries per unit time is exactly the reciprocal of our performance definition2. The minimum time granularity that MySQL can store is seconds (MariaDB supports second level time types)3. DataTime: independent of time zone, it uses 8 fields of storage space in the format ofInteger of yyyymmddhhmmss4. Timestamp: uses 4 […]

  • Mybatis [14] – how does mybatis implement one to many query?


    Note: the code is hosted on GitHub at:https://github.com/Damaer/Mybatis-LearningThe project ismybatis-10-one2many, need to be self fetched, need to be configuredmavenEnvironment andmysqlEnvironment(sqlStatement inresourceNexttest.sqlIf you think it’s useful, you can point a little star. docsifyThe document address is at:https://damaer.github.io/Mybatis-Learning/#/ Many times, when the query criteria involve multiple tables with association relationship, you need to use association query. There […]

  • Android serial 9-fragment life cycle


    1、 The state and state of the debris 1. Operation status When a fragment is visible and its associated activity is running, the fragment is running. 2. Pause state When an activity enters the pause state (due to another activity that does not occupy the full screen being added to the top of the stack), […]

  • Pick up the source code of eventserviceprovider


    With the previous “Introduction to the use of laravel model events”https://mp.weixin.qq.com/s/XrhDq1S5RC9UdeULVVksoAI have a general ideaEventThe use of. Today we’re going to have a grillEventSource code of. Before we start, we need to say the next twoEventServiceProviderThe differences between them are as follows: App\Providers\EventServiceProvider Illuminate\Events\EventServiceProvider firstApp\Providers\EventServiceProviderMainly the definitioneventandlistenerA second connection; a second connectionIlluminate\Events\EventServiceProvideryesLaravelThe three foundations of […]

  • The result set with empty filtering result in laravel association model (the difference between has and with)


    First, look at the code $userCoupons = UserCoupons::with([‘coupon’ => function($query) use($groupId){ return $query->select(‘id’, ‘group_id’, ‘cover’, ‘group_number’, ‘group_cover’)->where([ ‘group_id’ => $groupId, ]); }]) //More queries omitted The data structure is a three table user coupon table_ Coupons, coupons, corps, group coupons_ Coupons) (the latter two items have been removed for convenience) Here, I intend to use […]

  • Hands on how to create and start AWS instances


    What is AWS? Amazon Web services (AWS) is the most comprehensive and widely used cloud platform in the world provided by Amazon. The concept of cloud was first heard from Alibaba cloud and Tencent cloud in China. Later, with more contact with servers, we gradually learned about some foreign clouds, such as Amazon cloud and […]

  • Public beta launch | API enabled linked smart tables, how does “Vika Vig” make digitization truly productive?


    Vika wiggle table, is a connected smart form supporting API, a new generation of team data collaboration and project management artifactNo need to download, online use:vika.cnAPI SDK: vika.js There are so many software tools on the market, but few of them can connect and integrate well, and really help us to work and live better. […]

  • Hand in hand to teach you how to create a startup azure instance


    Examples of Google cloud and AWS are as follows: Hand in hand how to create and start Google cloud instance Hands on how to create and start AWS instances get ready Because this article is to create Microsoft cloud, so first you have to have a Microsoft account. Open Microsoft azure to login. After successful […]

  • WPF’s inner world (binding)


    catalog 1、 Control and layout 2、 Binding Foundation preface “A bridge Flying North and south, a natural moat becoming a thoroughfare” Written in 1956, Wuhan Yangtze River Bridge was completed in 1957. It is called “one bridge flying from north to south, a great moat changing into a thoroughfare”. It vividly describes the magnificent momentum […]

  • Fast generation of parent in front end_ Tree structure data associated with ID


    If you want to see the conclusion directly, you can jump toFast generation method In tob projects, it is inevitable to process tree related data, such as multi-level Department list, multi-level distribution list, and so on. For all cascading data with upper and lower levels, it is inevitable to generate tree structure data. There are […]

  • Elasticsearch index lifecycle management scheme


    1、 Preface stayElasticsearchIn our daily life, there are many things like storagesystem log、Behavioral dataThese scenarios are characterized by a large amount of data, and with the growth of timeIndexesHowever, in these scenarios, only the data of the latest period is valuable or frequently used (hot data), while historical data is almost useless or rarely used […]

  • (MAC) PHP extension installation


    A series of articles: (MAC) PHP installation and configuration Configuration parameter of PHP compilation and installation (MAC) PHP extension installation Configuration of php-fpm and nginx Default configuration of php-fpm preface Everyone’s installation environment is different, the specific installation depends on the individual! 1. Check before installingphp.iniAnd then write the extension to the configuration file. php […]