如何在 ionic 2/3 中处理数据库异步操作

Question

我正在使用 ionic 中的数据库，我调用了一个返回许多记录的 API，我必须将这些记录插入数据库以及何时完成插入操作然后我想要从数据库中调用选择记录。问题是异步行为，在插入操作完成之前调用数据库中的选择记录。谁能帮我解决这个问题？我的代码在下面...

数据库提供者：

export class DbProvider {


  public addData(dId: string, sId: string, subId: string, subName: string,
    dDate: string, cId: string, cName: string, stdId: string, stdName: string,
  ) {
    return new Promise((resolve, reject) => {
      this.db.executeSql("INSERT INTO data (dId , sId , subId , subName ," +
        " dDate , cId , cName , stdId , stdName ) VALUES (?, ?,?, ?,?, ?,?, ?,?)",
        [dId, sId, subId, subName, dDate, cId, cName, stdId, stdName]).then((data) => {
          resolve(data);
        }, (error) => {
          reject(error.tostring());
        });
    });
  }

}

数据库插入和调用

for (let temp of ApiData) {

  this.DbHandler.IsAvailable(temp.dId).then(data => {


    if (data) {
      console.log("did Available editing " + data);

      this.DbHandler.editData(temp.dId, temp.sId, temp.subId, temp.subName,
        temp.dDate, temp.cId, temp.cName);


    } else {
      console.log("did not Available inserting " + data);

      this.DbHandler.addData(temp.dId, temp.sId, temp.subId, temp.subName,
        temp.dDate, temp.cId, temp.cName);

    }
  });
}

this.getDataFromDb();

在开始 SELECT 请求之前，我想完成多个 INSERT。我的问题是 SELECT 触发时 INSERT 尚未完成。

Answer 1

在then方法中调用从DB读取：

let promises = [];
for (let temp of ApiData) {
  let promise = new Promise((resolve, reject) => {
    this.DbHandler.IsAvailable(temp.dId).then(data => {
      if (data) {
        console.log("did Available editing " + data);
        this.DbHandler.editData(temp.dId, temp.sId, temp.subId, temp.subName,
          temp.dDate, temp.cId, temp.cName).then(() => resolve());
      } else {
        console.log("did not Available inserting " + data);
        this.DbHandler.addData(temp.dId, temp.sId, temp.subId, temp.subName,
          temp.dDate, temp.cId, temp.cName).then(() => resolve());
      }
    });
  };
  promises.push(promise);
}
Promise.all(promises).then(() => this.getDataFromDb());