How could I make a transaction using multiple php controllers to make the queries?
Currently, my code is like this (A bit more complex, but I am not allowed to show anymore)
$operation = new Operations();
$bill = new Bills();
$employee = new Employee();
$operation->setName("Name");
$operationCreated = $operation->create();
$result = "";
if($operationCreated){
$bill->setAmount(1000);
$billCreated = $bill->create();
if($billCreated){
$employee->setName("Name");
$result= $employee->create();
}
}
return $result;
The way it is right now leads to a problem where I might have an operation created well, but no billing and no employee and my database ends with a row I don't want because I don't have all the information I need in the database.
I need a way to revert the changes if any one of them fails, and I think a transaction would do the trick, but I don't know how can be done. All three classes extend the Database class that has the create() method.
Related
my problem is that with a job (done in laravel 5.7) I need to change the codes of some promotions every day, the problem with the code that I have made changes the promotion code but it is the same for everyone, and I need it different for each of the promotions.
my code
DB::table('promociones')->update(['codigo_promocion'=>str_random(4)]);
If you don't have a lot of data like thousands of rows to update you can use a loop for it.
Using Eloquent:
$promociones = Promociones::all();
foreach($promociones as $promocion) {
$promocion->codigo_promocion = $this->generateUniqueString();
$promocion->save();
}
or by using query builder:
$promociones = DB::table('promociones')->get();
forea ch($promociones as $promocion) {
DB::table('promociones')
->where('id', $promocion->id)
->update(['codigo_promocion'=> $this->generateUniqueString()]);
}
And the generateUniqueString should check if the string is already inserted in the database:
private function generateUniqueString()
{
while(true) {
$randomString = str_random(4);
$doesCodeExist = DB::table('promociones')
->where('codigo_promocion', $randomString)
->count();
if (! $doesCodeExist) {
return $randomString;
}
}
}
Use where() if you need to filter the data.
Keep in mind if you have a lot of data you should consider using an approach like queues for example.
A simple way to handle this would be looping:
$promotions = Promocione::where(...)->get();
// Note, replace `...` with logic to target specific codes that need to be changed today.
foreach($promotions AS $promotion){
$promotion->codigo_promocion = str_random(4);
$promotion->save();
}
This assumes you have a Promocione model, and can be very performance intensive depending on the number of records in the database. Also, str_random(4) doesn't guaranteed a random value (in comparison to other uses of str_random(4) in the same loop), nor does it provide a large pool of random values, so you'll likely end up with duplicates. You can query for existing duplicates while looping, and generate a new code if you find one, but as you exhaust your pool of str_random(4) codes, this process will "lock up" to the eventually point of infinite execution.
We have a COMMON database and then tenant databases for each organization that uses our application. We have base values in the COMMON database for some tables e.g.
COMMON.widgets. Then in the tenant databases, IF a table called modified_widgets exists and has values, they are merged with the COMMON.widgets table.
Right now we are doing this in controllers along the lines of:
public function index(Request $request)
{
$widgets = Widget::where('active', '1')->orderBy('name')->get();
if(Schema::connection('tenant')->hasTable('modified_widgets')) {
$modified = ModifiedWidget::where('active', '1')->get();
$merged = $widgets->merge($modified);
$merged = array_values(array_sort($merged, function ($value) {
return $value['name'];
}));
return $merged;
}
return $countries;
}
As you can see, we have model for each table and this works OK. We get the expected results for GET requests like this from controllers, but we'd like to merge at the Laravel MODEL level if possible. That way id's are linked to the correct tables and such when populating forms with these values. The merge means the same id can exist in BOTH tables. We ALWAYS want to act on the merged data if any exists. So it seems like model level is the place for this, but we'll try any suggestions that help meet the need. Hope that all makes sense.
Can anyone help with this or does anyone have any ideas to try? We've played with overriding model constructors and such, but haven't quite been able to figure this out yet. Any thoughts are appreciated and TIA!
If you put this functionality in Widget model you will get 2x times of queries. You need to think about Widget as an instance, what I am trying to say is that current approach does 2 queries minimum and +1 if tenant has modified_widgets table. Now imagine you do this inside a model, each Widget instance will pull in, in a best case scenario its equivalent from different database, so for bunch of Widgets you will do 1 (->all())+n (n = number of ModifiedWidgets) queries - because each Widget instance will pull its own mirror if it exists, no eager load is possible.
You can improve your code with following:
$widgets = Widget::where('active', '1')->orderBy('name')->get();
if(Schema::connection('tenant')->hasTable('modified_widgets')) {
$modified = ModifiedWidget::where('active', '1')->whereIn('id', $widgets->pluck('id'))->get(); // remove whereIn if thats not the case
return $widgets->merge($modified)->unique()->sortBy('name');
}
return $widgets;
OK, here is what we came up with.
We now use a single model and the table names MUST be the same in both databases (setTable does not seem to work even though in exists in the Database/Eloquent/Model base source code - that may be why it's not documented). Anyway = just use a regular model and make sure the tables are identical (or at least the fields you are using are):
<?php
namespace App\Models;
use Illuminate\Database\Eloquent\Model;
class Widget extends Model
{
}
Then we have a generic 'merge controller' where the model and optional sort are passed in the request (we hard coded the 'where' and key here, but they could be made dynamic too). NOTE THIS WILL NOT WORK WITH STATIC METHODS THAT CREATE NEW INSTANCES such as $model::all() so you need to use $model->get() in that case:
<?php
namespace App\Http\Controllers;
use Illuminate\Http\Request;
use Illuminate\Support\Facades\Config;
use Illuminate\Support\Facades\DB;
use Illuminate\Support\Facades\Schema;
class MergeController extends Controller
{
public function index(Request $request)
{
//TODO: add some validations to ensure model is provided
$model = app("App\\Models\\{$request['model']}");
$sort = $request['sort'] ? $request['sort'] : 'id';
$src_collection = $model->where('active', '1')->orderBy('name')->get();
// we setup the tenants connection elsewhere, but use it here
if(Schema::connection('tenant')->hasTable($model->getTable())) {
$model->setConnection('tenant');
$tenant_collection = $model->get()->where('active', '1');
$src_collection = $src_collection->keyBy('id')->merge($tenant_collection->keyBy('id'))->sortBy('name');
}
return $src_collection;
}
}
If you dd($src_collection); before returning it it, you will see the connection is correct for each row (depending on data in the tables). If you update a row:
$test = $src_collection->find(2); // this is a row from the tenant db in our data
$test->name = 'Test';
$test->save();
$test2 = $src_collection->find(1); // this is a row from the tenant db in our data
$test2->name = 'Test2'; // this is a row from the COMMON db in our data
$test2->save();
dd($src_collection);
You will see the correct data is updated no matter which table the row(s) came from.
This results in each tenant being able to optionally override and/or add to base table data without effecting the base table data itself or other tenants while minimizing data duplication thus easing maintenance (obviously the table data and population is managed elsewhere just like any other table). If the tenant has no overrides then the base table data is returned. The merge and custom collection stuff have minimal documentation, so this took some time to figure out. Hope this helps someone else some day!
Please be gentle with me - I'm a Laravel noob.
So currently, I loop through a load of users deciding whether I need to update a related model (UserLocation).
I've got as far as creating a UserLocation if it needs creating, and after a bit of fumbling, I've come up with the following;
$coords = $json->features[0]->geometry->coordinates;
$location = new UserLocation(['lat'=>$coords[1],'lng'=>$coords[0]]);
$user->location()->save($location);
My issue is that one the second time around, the Location may want updating and a row will already exist for that user.
Is this handled automatically, or do I need to do something different?
The code reads like it's creating a new row, so wouldn't handle the case of needing to update it?
Update - solution:
Thanks to Matthew, I've come up with the following solution;
$location = UserLocation::firstOrNew(['user_id'=>$user->id]);
$location->user_id = $user->id;
$location->lat = $coords[1];
$location->lng = $coords[0];
$location->save();
You should reference the Laravel API Docs. I don't think they mention these methods in the "regular docs" though so I understand why you may have not seen it.
You can use the models firstOrNew or firstOrCreate methods.
firstOrNew: Get the first record matching the attributes or instantiate
it.
firstOrCreate: Get the first record matching the attributes or create it.
For Example:
$model = SomeModel::firstOrNew(['model_id' => 4]);
In the above example, if a model with a model_id of 4 isn't found then it creates a new instance of SomeModel. Which you can then manipulate and later ->save(). If it is found, it is returned.
You can also use firstOrCreate, which instead of creating a new Model instance would insert the new model into the table immediately.
So in your instance:
$location = UserLocation::firstOrNew(['lat'=>$coords[1],'lng'=>$coords[0]]);
$location will either contain the existing model from the DB or a new instance with the attributes lat and lng set to $coords[1] and $coords[0] respectively, which you can then save or set more attribute values if needed.
Another example:
$location = UserLocation::firstOrCreate(['lat'=>$coords[1],'lng'=>$coords[0]]);
$location will either contain the existing model from the DB or a new model with the attributes set again, except this time the model will have already been written to the table if not found.
Here is situation.... ...
I have a DBManager, which is implement a DBInterface, in the DBInterface, I got 4 method:
-create(DBCmd);
-read(DBCmd);
-update(DBCmd);
-delete(DBCmd);
The DBCmd object is responsible for generate the SQL statement, and the DBCmd requires an object in sql statement:
class DBCmd{
public _constructor($aObj){
}
public executeCreate(){
}
public executeRead(){
}
public executeUpdate(){
}
public executeDelete(){
}
}
The flow will be like this:
aObject ---> put it into DBCmd ----> put the DBCmd in DBManager ---> execute
But the problems happen when I get some objects related to other tables, for example...a customer have a purchase record, and which purchase record have many items....
So, what do I do in my read method? should I read all the records related to the customer?? Do I need to loop all the items inside the purchase record too?
If yes, when I doing read customer, I need to query 3 tables, but some that may not need to see.....it waste the resource...
And I come up with another solution, I make a new set of DBCmd, that allow me to get the related DB items, for example:
class getReleatedPurchaseRecordDBCmd{
public _constructor($aCustomerObject){
}
//.... ....
}
But in this "solution", I got some problems, is I loss the relationship in the object customer...yes, I can read back all the records, get the customer object basically don't know any things about the purchase record....
Some may ask me to do something like this:
class customer{
//skip other methods...
public getPurchaseRecords(){
//query the db
}
}
It works, but I don't want the object structure have some strong relationship between the db....That's why I come up with the DBCmd stuff...
So, everything seems to be very coupling, how can solve it? Thank you.
for stuff like this i tend to get the count of sub objects with the initial query usually involving sql COUNT and JOIN, then have a seperate getSubObjects command that can be called if needed later. So for example:
$datamodel->getCustomer($id);//or some such method
returns
class Customer{
$id = 4;
$recordCount = 5;
$records = null;
}
I can then use the count for any display stuff as needed, and if i need the records populated call:
$customer->records = $datamodel->getCustomerRecords($customer->id);
The only way I found to do this is:
$mongo->selectDB('new_db')->createCollection('tmp_collection');
$mongo->selectDB('new_db')->dropCollection('tmp_collection');
Doing just $mongo->selectDB('new_db') actually doesn't work.
Got any idea?
You'll need to run at least one command on the Database before it is created ...
This command can be run before you add any Collections ... so you can merely list (the nonexistent) Collections.
<?php
$connection = new Mongo();
$db = $connection->foo;
$list = $db->listCollections();
foreach ($list as $collection) {
echo "$collection </br>";
}
?>
Your new Database should now exist, with no user Collections created yet.
Technically, you don't need to manually create databases or collections in MongoDB due to its schemaless "lazy" way of creating databases and collections.
I understand if you're coming from an SQL world this doesn't make much sense. You may want to ask yourself though, "If it automatically creates a collection or database for me on the fly, is there really a need to define it ahead of time?"