如何遍历数组，并从数据库Angular 5中获取一些数据

import { Component } from '@angular/core';
import { DataService } from './data.service';

@Component({
  selector: 'app-root',
  template: `
    <h1>Data List</h1>
    <ul>
      <li *ngFor="let item of data">{{ item }}</li>
    </ul>
  `,
  styleUrls: ['./app.component.css']
})
export class AppComponent {
  data: any[];

  constructor(private dataService: DataService) {}

  ngOnInit() {
    this.getDataFromDatabase();
  }

  getDataFromDatabase() {
    this.dataService.getData().subscribe(
      (response) => {
        this.data = response;
      },
      (error) => {
        console.log(error);
      }
    );
  }
}

import { Injectable } from '@angular/core';
import { HttpClient } from '@angular/common/http';
import { Observable } from 'rxjs';

@Injectable({
  providedIn: 'root'
})
export class DataService {
  constructor(private http: HttpClient) {}

  getData(): Observable<any[]> {
    return this.http.get<any[]>('your-database-api-url');
  }
}

import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';
import { HttpClientModule } from '@angular/common/http';

import { AppComponent } from './app.component';
import { DataService } from './data.service';

@NgModule({
  declarations: [
    AppComponent
  ],
  imports: [
    BrowserModule,
    HttpClientModule
  ],
  providers: [DataService],
  bootstrap: [AppComponent]
})
export class AppModule { }