ionic4 - 第一次执行时的 SQLite 性能

Question

我正在使用带有离子的 SQLite

Ionic:

   Ionic CLI                     : 6.6.0 (C:\Users\ADEEL\AppData\Roaming\npm\node_modules\@ionic\cli)
   Ionic Framework               : @ionic/angular 5.0.5
   @angular-devkit/build-angular : 0.900.7
   @angular-devkit/schematics    : 9.0.7
   @angular/cli                  : 9.0.7
   @ionic/angular-toolkit        : 2.2.0

Cordova:

   Cordova CLI       : 9.0.0 (cordova-lib@9.0.1)
   Cordova Platforms : android 8.1.0, browser 6.0.0
   Cordova Plugins   : cordova-plugin-ionic-webview 4.1.3, (and 9 other plugins)

Utility:

   cordova-res (update available: 0.13.0) : 0.6.0
   native-run (update available: 1.0.0)   : 0.2.8

System:

   Android SDK Tools : 26.1.1 (C:\Users\ADEEL\AppData\Local\Android\Sdk)
   NodeJS            : v12.16.1 (C:\Program Files\nodejs\node.exe)
   npm               : 6.13.4
   OS                : Windows 10

我有一个表，在 log_book 表中有 16 条记录，在部门和位置各有 1 条记录。当我第一次运行查询时，它将花费将近 15 到 20 秒，但之后它会以毫秒为单位运行。调用函数如下

getLogBooks(): Promise<LogBook[]>{
return this.storage.executeSql(`SELECT l.id, l.log_book_id, IFNULL(l.machine_no, "") machine_no , d.department_name, loc.location_name, l.section, l.area
FROM log_book l
INNER JOIN departments d ON l.department_id = d.id
INNER JOIN locations loc ON l.location_id = loc.id
WHERE l.deleted_at IS NULL`, [])
.then(res => {
  const items: LogBook[] = [];
  console.log('Log BOOK', res.rows.length)
  if (res.rows.length > 0) {
    for (let i = 0; i < res.rows.length; i++) {
      items.push({
        id: res.rows.item(i).id,
        LogBookID: res.rows.item(i).log_book_id,
        MachineNo: res.rows.item(i).machine_no,
        Department: res.rows.item(i).department_name,
        Location: res.rows.item(i).location_name,
        Section: res.rows.item(i).section,
        Area: res.rows.item(i).area
       });
    }
  }
  return items;
});

}

表结构

    CREATE TABLE IF NOT EXISTS `log_book` (
      `id` integer primary key autoincrement,
      `log_book_id` varchar(50) NOT NULL,
      `machine_no` varchar(50) DEFAULT NULL,
      `department_id` int(11) NOT NULL,
      `location_id` int(11) NOT NULL,
      `section` varchar(50) NOT NULL,
      `area` varchar(50) NOT NULL,
      `created_at` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
      `updated_at` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
      `created_by` int(11) DEFAULT NULL,
      `updated_by` int(11) DEFAULT NULL,
      `deleted_at` datetime DEFAULT NULL
    );

CREATE TABLE IF NOT EXISTS `departments` (
  `id` integer primary key autoincrement,
  `department_name` varchar(50) NOT NULL,
  `created_at` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
  `updated_at` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
  `created_by` int(11) DEFAULT NULL,
  `updated_by` int(11) DEFAULT NULL,
  `deleted_at` datetime DEFAULT NULL
);

CREATE TABLE IF NOT EXISTS `locations` (
  `id` integer primary key autoincrement,
  `location_name` varchar(50) NOT NULL,
  `created_at` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
  `updated_at` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
  `created_by` int(11) DEFAULT NULL,
  `updated_by` int(11) DEFAULT NULL,
  `deleted_at` datetime DEFAULT NULL
);

我做错了什么。

感谢你在期待

标签： ionic4