使用现有数据库（模型）

Question

Can i use play framework linked to an existing database (Example SAP DBB) to only display:

Dashboards (Queries)
Charts (Queries)

I developped an authentication page, suddenly, i did not tought about how to extract data from an existing database without declaring models!

What is the good way to only extract with many queries data and display it on views scala (Play framework JAVA)?

Thank you so much

Answer 1

We also have many existing databases, without having a complete model of each table in Play applications. I create a case class in the Play application for all necessary fields, also a subset of all columns. It's Scala code, but also possible with Java, of course.

  case class Positionstext(akt_abnr: Int
                   , akt_text_art: Int
                   , akt_text_pos: Int
                   , akt_text: String) {

}

The carefully assembled SQL command retrieves rows from one or more tables.

  def positionstexte(x: Int) : List[Positionstext] = {

    DB.withConnection{ connection =>

    val select =
      """ select plr_ak_texte.akt_abnr
               , plr_ak_texte.akt_text_art
               , plr_ak_texte.akt_text_pos
               , plr_ak_texte.akt_text
            from plrv11.plr_ak_texte
               , plrv11.plr_auftr_status
           where plr_ak_texte.akt_abnr     =  plr_auftr_status.as_abnr
             and plr_ak_texte.akt_aend_ix  =  plr_auftr_status.as_aend_ix
             and plr_ak_texte.akt_abnr     =  ?
             and plr_ak_texte.akt_text_art =  7
             and plr_auftr_status.as_aend_ix <> 99
       """

    val prepareStatement = connection.prepareStatement(select)

    prepareStatement.setInt(1, x)

    val rs = prepareStatement.executeQuery

    var list: ListBuffer[Positionstext] = scala.collection.mutable.ListBuffer()

    while (rs.next) {
      list += new Positionstext(rs.getInt("akt_abnr")
                            , rs.getInt("akt_text_art")
                            , rs.getInt("akt_text_pos")
                            , rs.getString("akt_text"))
    }
    rs.close()
    prepareStatement.close()
    list.toList
  }

And that's it, The SQL command already does most of the work by using sub-queries. joins etc.

All desired objects are in the list now and can display in the view.

Answer 2

Thank you for your return,

This is what i did and it works pretty fine:

package controllers;

import models.Sysuser;
import models.DataI;
import models.DataII;
import play.mvc.Controller;
import play.mvc.Result;
import play.mvc.Security;
import views.html.sitemap.index;

import javax.inject.*;
import java.util.concurrent.CompletionStage;
import play.libs.concurrent.HttpExecutionContext;
import static java.util.concurrent.CompletableFuture.supplyAsync;

import io.ebean.*;
import play.Logger;
import java.util.List;
import play.libs.Json;
import java.util.*;
import java.util.stream.*;

@Security.Authenticated(Secured.class)
public class SiteMap extends Controller {

    private final HttpExecutionContext httpExecutionContext;
    private static final Logger.ALogger logger = Logger.of(SiteMap.class);

    @Inject
    public SiteMap(HttpExecutionContext httpExecutionContext) {
        this.httpExecutionContext = httpExecutionContext;
    }   



    public CompletionStage<Result> index() {
      return supplyAsync(() -> {          
        return ok(views.html.sitemap.index.render(Sysuser.findByUserName(request().username()), QueryI(), QueryII() ));
        }, httpExecutionContext.current());
    }


    /**
     * Custom Query 1
     */ 
    public List<DataI> QueryI() {
                final String sql =  "SELECT sysuser_id, role_id "
                                   +"from sysuser_role "
                                   +"where sysuser_id = '1' "
                                   +"and role_id in ('1','2','3','4','5') ";
                final RawSql rawSql = RawSqlBuilder.parse(sql).create();                
                Query<DataI> query = Ebean.find(DataI.class);  
                query.setRawSql(rawSql);
                List<DataI> L = query.findList();
    return(L);
    }


    /**
     * Custom Query 2
     */ 
    public List<DataII> QueryII() {
                final String sql =  "SELECT sysuser.name, sysuser.active, department.description "
                                   +"from sysuser "
                                   +"left join department on department.id = sysuser.department_id "
                                   +"where sysuser.id = '2' ";
                final RawSql rawSql = RawSqlBuilder.parse(sql).create();                
                Query<DataII> query = Ebean.find(DataII.class);  
                query.setRawSql(rawSql);
                List<DataII> L = query.findList();
    return(L);
    }   





}

I am using Java instead of Scala, however, i don't think that there is a need of these codes such as: 1- DB.withConnection{ connection => 2- val prepareStatement = connection.prepareStatement(select)....and what else...

What do you think about my code? is it optimal? I am going to use complexe queries to fill some dashboards in this template: https://adminlte.io/themes/v3/index.html