i work with an exist sqlite database, and i want to display a random row from it.
i followed this steps , but it display the row with the name of the column and the brakets.
this is the code i used :
var name;
void _query() async {
Database db = await DatabaseHelper.instance.database;
List<Map> result = await db.rawQuery('SELECT content FROM $table ORDER BY random() LIMIT 1');
setState(() {
result.forEach((row){
print(row);
name= result;
});
});
}
in the builder, i use this :
Container(
child: Text('${name}'),
),
RaisedButton(
child: Text('Generate another'),
onPressed: (){
_query()
;},
),
the result in terminal {content:james}
and in the emulator [{content:james}]
i want to display just : james
thank you
result is a List of Map so you can use first & correct key to access the desired result.
setState(() {
name = result.first['content']; // james
});
A solution would be to convert your output to a list before going through it.
outputList = result.values.toList(); as it is stated in this answer
Related
i have a collection of questions which contain an array of strings of id of user liked this questions
i want to check if an id exist in this array then show a widget
List result = await FirebaseFirestore.instance
.collection('QuestionBank')
.doc(questionID)
.snapshots()
.map((event) => {List.from(event['userLiked'])})
.toList();
return result.contains(uid);
}
this is how i add item in array
Future<void> updateQuestionLikes(String uids, String userUid) async {
await questionBank.doc(uids).set({
'likes': FieldValue.increment(1),
'userLiked': FieldValue.arrayUnion([userUid])
}, SetOptions(merge: true));
}
i wan to check if a uid exist in userLiked field in the firestore
does not work
any ideas or solutions can help ?
I suppose it's that:
Future<bool> ifUidExist(String uid)async {
final query = await FirebaseFirestore.instance
.collection("QuestionBank")
.where("userLiked", arrayContains: uid)
.get();
return query.docs.isNotEmpty;
}
Here I want to add bookmark functionality in my flutter news application. I get data from APIs. I display that data below.
This Image shows you how I get data from APIs
I am using this snippet for saving data with SQflite which I display below. I save this file with name bookmark_db_provider.dart.
import 'dart:io';
import 'home_screen_data.dart';
import 'package:path/path.dart';
import 'package:path_provider/path_provider.dart';
import 'package:sqflite/sqflite.dart';
class DBProvider {
static Database _database;
static final DBProvider db = DBProvider._();
DBProvider._();
Future<Database> get database async {
if (_database != null) _database = await initDB();
return _database;
}
initDB() async {
Directory documentsDirectory = await getApplicationDocumentsDirectory();
final path = join(documentsDirectory.path, 'ProductData.db');
return await openDatabase(path, version: 1, onOpen: (db) {},
onCreate: (Database db, int version) async {
await db.execute('CREATE TABLE ProductData('
'id INTEGER PRIMARY KEY,' //id
'categoryName Text,' //headline
'publisherName Text,' //description
'isAvailable Text,' //content
'categoryImgUrl Text' //image
')');
});
}
createProductData(ProductData productData) async {
await deleteAllProductData();
final db = await database;
final res = await db.insert('ProductData', productData.toJson());
return res;
}
Future<int> deleteAllProductData() async {
final db = await database;
final res = await db.delete('DELETE FROM ProductData');
return res;
}
Future<List<ProductData>> getProductDataList() async {
final db = await database;
final res = await db.rawQuery("SELECT * FROM ProductData");
List<ProductData> list = res.isNotEmpty ? res.map((x) => ProductData.fromJson(x)).toList() : [];
return list;
}
}
So, I want to how to save data and get data this with SQflite database in flutter. How I accomplish this?
This is an old question and hopes you have gotten an answer to it. However, a lot of flutter dev using sqflite struggles with handling data in a nested array format of the type mentioned e.g
``` {
"id": 1,
"name": "xyz",
"images": [
{
"imageId": 1,
"image": "image1"
},
{
"imageId": 2,
"image": "image2"
}
]
}
```
Since json handling is not part of sqflite at the moment, it is suggested to either;
a., save inner array as a string/text field in the 'image' column of table 'data' like
**
"[{"imageId": 1, "image": 'image1'}, {"imageId": 2, "image":
'image2'},}"
** , no guaranty.
or, b., flatten out the inner array so as to have only **
data[id, name, image1, image2, image3,...].
** this approach may be possible in a simple array as given but in a complex system. flattening out may be really cumbersome.
my suggestion, create two tables, one for data, and another for images. let each row of images table have reference or relationship with corresponding data table row. Your data class and images class will be something like,
```
class Data {
int dataId;
String name;
List<Image> images;
data({this.id, this.images, this.name});
...
```
and
```
class Image {
int imageId;
int dataId;
String image;
Image({this.imageId, this.dataId, this.image});
...
}
```
Your sqflite table data will have only two fields 'dataId' and 'name' and the image table must include 'dataId' as the relationship between the two tables.
to save data, you can use transactions like
```
void saveData(Data data, Map<String, Object> map) async {
await db.execute(""" INSERT INTO "data" (name) values (?) """, [data.name]);
// retrieve dataId of the new row inserted. last_inserted_rowid can also be used if the database does not contain several tables that may have been updated or saved before completing the transaction.
int dataId;
List<Map> x = await db.query('data', columns: ['dataId'], where: 'name = ?', whereArgs: [data.name]);
dataId = x[x.length - 1]['dataId'];
db.transaction((txn) async {
var batch = txn.batch();
data.images
.map((e) => {
batch.rawInsert(
""" INSERT INTO "images" (dataId,image,) values (?,?,?,? ) """, [dataId, e.image])
}).toList();
});
}
```
to retrieve data and images, you can try something like
```
Data _data = new Data();
Future<void> fetchData() async {
if (db != null) {
// do not execute if db is not instantiate
//retrieve all data from data table and store in instantiated, also instantiate images array as empty list
final dataList = await db.query(data);
_data = (dataList as List)
.map(
(data) => Data(
dataId: data['dataId'],
name: data['name'],
images: data['images'] != null ? data['images'] : []
)) .toList();
_data.forEach((data) async {if (data.images != null) {
List<Image> _images = [];
var imageResults = await db.query(images,where: 'dataId =?', whereArgs: [data.dataId]);
_images = (imageResults as List).map((e) => Image(
imageId: e['imageId'],
dataId: e['dataId'],
image: e['image']
)).toList();
_data.images.addAll(_images);
} });
}
}
```
with that approach, you should be able to handle nested array in flutter and sqflite
I might be unclear with your question, but according to what I understood,
You need to call the method of this provider with data that you want:
DBProvider.init() // Use this only one which when the application is instaled
After that, you can call these methods from anywhere to put and get data
DBProvider.createProductData(productData) //insert data
Get data
DBProvider.getProductDataList() //get data
I have threads and messages on thread
I want to return all threads with the last message time, so I added a new field like this on thread model
public function fields()
{
$fields= ['idThread', 'idUser', 'title', 'unread', 'username','lastMesageTime'];
return $fields;
}
now with this method I get the calculated value lastMessageTime
public function getLastMessageTime()
{
return $this->hasMany(Messages::className(), ['idThread' => 'idThread'])
->select('time')->orderBy('time DESC')->limit(1)->scalar();
}
on my index method using active record like this
return Thread::find()->select('idThread, title, idUser')->all();
this works and I get lastMessageTime with the right value, but I want to order by so I can get the thread with the most recent lastMessageTime the first one, I tried with the following code
public function scopes() {
return array(
'byOrden' => array('order' => 'lastTimeMessage DESC'),
);
}
any idea?
Edit:
this workaround works, but I think this is not a good way because I'm not using active record so fields like username that I had defined on Thread model I had to fetch it again
$query = (new \yii\db\Query());
$query->select('*, (SELECT max(time) as lastMessageTime from messages where messages.idThread = thread.idThread ) lastMessageTime,
(SELECT name from users where users.idUser = thread.idUser) as name ')
->from('threads')
->where(['idUser'=>$idUser])
->orderBy('lastMessageTime DESC');
$rows = $query->all();
return $rows;
You can define extra fields as model properties, then override find method to load data for them.
class Thread extends \yii\db\ActiveRecord
{
public $lastMessageTime;
public static function find()
{
$q = parent::find()
->select('*')
->addSelect(
new \yii\db\Expression(
'(SELECT max(time) FROM messages WHERE messages.idThread = thread.idThread) AS lastMessageTime'
);
return $q;
}
}
Then you can load and order models like this:
$rows = Thread::find()->orderBy(['lastMessageTime' => SORT_DESC])->all();
I don't know the syntax to access "CurrentTable.ForeignKey" nor "OtherTable.PrimaryKey" in a $model->addCondition() statement.
This is a fragment of my code which works:
$mm = new SYSPC_MODEL($this->app->db,['title_field'=>'MODEL_NAME']);
$mm->addCondition('MODEL_NAME', 'LIKE', 'DESK%');
In place of simply searching for MODEL_NAME like 'DESK%', I would like to display only the FK_MODEL_id values which exist in the SYSPC_MODEL table for the same FK_OS_ID than the current record FK_OS_ID value. So in SQL, we should have something like:
SELECT SYSPC_MODEL.MODEL_NAME WHERE ( DHCP_PC.FK_OS_ID = SYSPC_MODEL.id )
To understand easier the context, I reduced my code as much as possible:
<?php
include_once ('../include/config.php');
require '../vendor/autoload.php';
class SYSPC_OS extends \atk4\data\Model {
public $table = 'SYSPC_OS';
function init() {
parent::init();
$this->addFields([ ['OS_NAME', 'required'=>true, 'caption'=>'Identifiant d\'OS'],
['OS_DESCRIPTION', 'required'=>true, 'caption'=>'Description d\'OS']
]);
}
} // End of class SYSPC_OS
class SYSPC_MODEL extends \atk4\data\Model {
public $table = 'SYSPC_MODEL';
function init() {
parent::init();
$this->addFields([ ['MODEL_NAME', 'caption'=>'Nom du modele'],
['MODEL_BASE_RPM', 'caption'=>'Rpm de base']
]);
$this->hasOne('FK_OS_id',[new SYSPC_OS(),'ui'=>['visible'=>false]])->addField('OS_NAME','OS_NAME');
}
} // End of class SYSPC_MODEL
class DHCP_PC extends \atk4\data\Model {
public $table = 'DHCP_PC';
function init() {
parent::init();
$this->addFields([ ['PCNAME', 'required'=>true, 'caption'=>'Nom du pc']
]);
$this->hasOne('FK_OS_ID',['required'=>true,new SYSPC_OS(),'ui'=>['visible'=>false]])->addField('OS_NAME','OS_NAME');
$this->setOrder('PCNAME','asc');
$this->hasOne('FK_MODEL_id',['required'=>true,new SYSPC_MODEL(),'ui'=>['visible'=>false]])->addField('MODEL_NAME','MODEL_NAME');
}
} // End of class DHCP_PC
class PcForm extends \atk4\ui\Form {
function setModel($m, $fields = null) {
$PcWidth = 'three';
parent::setModel($m, false);
$gr = $this->addGroup('PC name');
$gr->addField('PCNAME',['required'=>true,'caption'=>'Nom du pc']);
$gr = $this->addGroup('OS');
$mm2 = new SYSPC_OS($this->app->db,['title_field'=>'OS_NAME']);
$gr->addField('FK_OS_ID',['width'=>$PcWidth],['DropDown'])->setModel($mm2);
$gr = $this->addGroup('Modèle');
$mm = new SYSPC_MODEL($this->app->db,['title_field'=>'MODEL_NAME']);
$mm->addCondition('MODEL_NAME', 'LIKE', 'DESK%'); // Works fine but I would like to display only the FK_MODEL_id values
// which exist in the SYSPC_MODEL table for the same FK_OS_ID
// than the current record FK_OS_ID value :
// SELECT SYSPC_MODEL.MODEL_NAME WHERE ( DHCP_PC.FK_OS_ID = SYSPC_MODEL.id )
$gr->addField('FK_MODEL_id', ['width'=>$PcWidth], ['DropDown'])->setModel($mm);
return $this->model;
}
} // End of class PcForm
$app = new \atk4\ui\App();
$app->title = 'Gestion des PC';
$app->initLayout($app->stickyGET('layout') ?: 'Admin');
$app->db = new \atk4\data\Persistence_SQL(
"pgsql:host=".$GLOBALS['dbhost'].";dbname=".$GLOBALS['dbname'],
$GLOBALS['dbuser'],
$GLOBALS['dbpass']
);
$g = $app->add(['CRUD', 'formDefault'=>new PcForm()]);
$g->setIpp([10, 25, 50, 100]);
$g->setModel(new DHCP_PC($app->db),['PCNAME', 'OS_NAME', 'MODEL_NAME']);
?>
Please look at https://github.com/atk4/ui/pull/551 - it might be what you're looking for.
Example here: https://ui.agiletoolkit.org/demos/autocomplete.php
Docs: https://agile-ui.readthedocs.io/en/latest/autocomplete.html?highlight=lookup#lookup-field
$form = $app->add(new \atk4\ui\Form(['segment']));
$form->add(['Label', 'Add city', 'top attached'], 'AboveFields');
$l = $form->addField('city',['Lookup']);
// will restraint possible city value in droddown base on country and/or language.
$l->addFilter('country', 'Country');
$l->addFilter('language', 'Lang');
//make sure country and language belong to your model.
$l->setModel(new City($db));
Alternatively you can use something other than drop-down, here is UI example:
https://ui.agiletoolkit.org/demos/multitable.php
Selecting value in the first column narrows down options in the next. You can have a hidden field inside your form where you can put the final value.
Thanks for your support but I still have some questions.
Question 1: I found "addRelatedEntity" and "relEntity" but I didn't found a description of those commands. Does it exist ? Is this a possible solution for my issue ?
Question 2: Is it possible to 'Lookup' in another table and if yes, how ?
Question 3: If 'Lookup' is not the solution, how to make a join (with filtering in the where clause) inside a model ?
Question 4: If the join is not the solution, is it possible to use DSQL inside a model ?
Question 5: Or do you have a DSQL example (with a self made join between several tables) associated with a CRUD ?
is there any way to ignore the first result record in Yii2 at a query? I have a list of numbers that represents a client. For designing purposes i had to query the first record separatly but now i have it duplicated. My questin is how can I query in Yii2 to ignore the first result?
Regards,
Gábor
The second find is the query where i need to ignore the first result:
public function actionGeneratePage() {
public function actionGeneratePage() {
$behivott = Sorszam::find()->with('ablak')
->orderBy(['behivas_datum' => SORT_DESC])
->limit(1)
->all();
$sorszamok = Sorszam::find()->with('ablak')
->orderBy(['behivas_datum' => SORT_DESC])
->limit(4)
->all();
$reklam = Reklam::find()->all();
return $this->render('generatePage', [
'sorszamok' => $sorszamok,
'reklam' => $reklam,
'behivott' => $behivott,
]);
}
You use offset() to skip the first record:
$sorszamok = Sorszam::find()->with('ablak')
->orderBy(['behivas_datum' => SORT_DESC])
->limit(4)
->offset(1)
->all();
Also you can use a single query to get both $behivott and $sorszamok with array_shift:
$sorszamok = Sorszam::find()->with('ablak')
->orderBy(['behivas_datum' => SORT_DESC])
->limit(5)
->all();
$behivott = array_shift($sorszamok);