$model = Person::findOne($person_id);
$model->status = $status;
$model->save();
or
Yii::$app->db->createCommand()->update('person',
['status'=>$status],
'person_id='.$person_id)
->execute();
In terms of performance, how this two snippet different from each other although the result is the same?
The firts is based on the fact the related active record is obtained by a preliminary select and then the change is performed by an update when the save() (and the related validation) method is invoked ..
The second don't perform a select for get the related activeRecord ..
and perform the update only
so the second should be more fast then the first ..
Using ActiveRecord (the first example) is generally more memory intensive (because of the object setup, teardown, validation etcetera).
The second one will be much faster but it does not validate the data. Most of the time you will want to work with a "small" set of ActiveRecords objects (that's why Yii2 has pagination in it's DataProviders). ActiveRecord is more powerful since you can traverse relations, use virtual attributes etc.
But for batch inserts the second one it is much better. And you can also use it like this to insert multiple rows in one query:
Yii::$app->db->createCommand()->batchInsert('tableName', ['id', 'title', 'created_at'], [
[1, 'title1', '2015-04-10'],
[2, 'title2', '2015-04-11'],
[3, 'title3', '2015-04-12'],
])->execute();
Related
i hope you are having a good time. i am learning laravel and the inscuctor talked about when you load relationships in laravel, like so
public function timeline()
{
$ids = $this->follows()->pluck('id');
$ids->push($this->id);
return Tweet::whereIn('user_id', $ids)->latest()->get();
}
and i have a follows relationship in my model, and he talked about this line
$ids = $this->follows()->pluck('id');
being better for performance than this line
$ids = $this->follows->pluck('id');
my question is, how does laravel pluck the ids in the first case, and how it queries the database
i hope im making sense, thanks for your time, and answer.
the following one executes a select query on database
$this->follows()->pluck('id');
the follows() returns a query builder (which is a not yet executed sql statement) and then on the result select the id column and returns a collection of ids
you can see the query by dumping the query builder by $this->follows()->dd()
Whereas in the second option
$this->follows->pluck('id')
up until $this->follows laravel executes a query and returns all the records as a collection instance, You will be able to see all the attributes on each of the records. And then ->pluck('id') is getting executed on the laravel collection class, which will do an operation I assume similar to the array_column function does and returns only the id column.
as you can easily see in the second operation the whole data set was retrieved first from the DB and then selected the required attribute/column (2 distinct and heavy operations). Where as in the first option we directly told eloquent to select only the required column, which is only one lighter operation compared to the second option.
I need to make an import method that takes the CSV file and imports everything in the database.
I've done the parsing with one of Laravel's CSV addons and it works perfectly giving me a big array of values set as:
[
'col1_name' => 'col1 value',
'col2_name' => 'col2 value',
'col3_name' => 'col3 value,
'...' => '...'
]
This is also perfect since all the column names fit my model which makes the database inserts a breeze.
However - a lot of column values are strings that i'd like to set as separate tables/relations. For example, one column contains the name of the item manufacturer, and i have the manufacturer table set in my database.
My question is - what's the easy way to go through the imported CSV and swap the strings with the corresponding ID from the relationship table, making it compatible with my database design?
Something that would make the imported line:
[
'manufacturer' => 'Dell',
]
into:
[
'manufacturer' => '32',
]
I know i could just do a foreach loop comparing the needed values with values from the relationship models but I'm sure there's an easier and more clean way of doing it.
I don't think theres any "nice" way to do this - you'll need to look up each value for "manufacturer" - the question is, how many queries will you run to do so?
A consideration you need to make here is how many rows you will be importing from your CSV file.
You have a couple of options.
1) Querying 1 by 1
I'm assuming you're going to be looping through every line of the CSV file anyway, and then making a new model? In which case, you can add an extra database call in here;
$model->manufacturer_id = Manufacturer::whereName($colXValue)->first()->id;
(You'd obviously need to put in your own checks etc. here to make sure manufacturers exist)
This method is fine relatively small datsets, however, if you're importing lots and lots of rows, it might end up sluggish with alot of arguably unnecessary database calls.
2) Mapping ALL your Manufacturers
Another option would be to create a local map of all your Manufacturers before you loop through your CSV lines;
$mappedManufacturers = Manufacturer::all()->pluck('id', 'name');
This will make $mappedManufacturers an array of manufacturers that has name as a key, id as a value. This way, when you're building your model, you can do;
$model->manufacturer_id = $mappedManufacturers[$colXValue];
This method is also fine, unless you have tens of thousands of Manufacturers!
3) Where in - then re-looping
Another option would be to build up a list of manufacturer names when looping through your CSV lines, going to the database with 1 whereIn query and then re-looping through your models to populate the manufacturer ID.
So in your initial loop through your CSV, you can temporarily set a property to store the name of the manufacturer, whilst adding it to another array;
$models = collect();
$model->..... = ....;
$model->manufacturer = $colXValue;
$models->push($colXValue);
Then you'll end up with a collection of models. You then query the database for ONLY manufacturers which have appeared:
$manufacturers = Manufacturer::whereIn('name', $models->lists('manufacturer'))->get()->keyBy('name')->toArray();
This will give you array of manufacturers, keyed by their name.
You then loop through your $models collection again, assigning the correct manufacturer id using the map;
$model->manufacturer_id = $manufacturers[$model->manufacturer];
Hopefully this will give you some ideas of how you can achieve this. I'd say the solution mostly depends on your use case - if this was going to be a heavy duty ask - I'd definitely Queue it and be tempted to use Option 1! :P
I understand the question might not be very clear but here is my situation. I'm using laravel 5 and i'm developing a CRM system. I have placed Marital Status and Sex/Gender into one Lookup table. Whenever i get the values from the database and pass it to the view, i have two separate queries.
$sexes = DB::table('Lookups')
->where('ValueType', '=', 'Sex')->get();`
$marstatus = DB::table('Lookups')
->where('ValueType', '=', 'Marital Status')->get();`
return view('clients.edit',compact('client'))
->with('sexes', $sexes)
->with('marstatus ', $marstatus );
This code actually works and i am able to get both the marital status and sex/gender on my view.
So, here is my question
Doesn't this mean that i am sending a query to the database twice which affects performance even if it is small
Isn't there a way to query all the values from the lookup table in one query and filter out the values on the controller. So it can be something like
$Lookups = DB::table('Lookups')
and then filter the $Lookups variable and assign it into two different variables ($sexes and $marstatus) based on my filter criteria. i.e ($sexes is for values that have ValueType = 'Sex' ...)
Which one is better for performance. Sending a query twice or three times or just filtering the data on the controller.
1) Yes it does. Just install Laravel Debugbar and see it yourself. It's a very handy tool strongly recommended.
2) Yes you can do that, laravel has nice helper functions for that type of needs:
$collection = collect(DB::table('Lookups')
->whereIn('ValueType', ['Marital Status', 'Sex'])
->get());
$marstatus = $collection->filter(function($item) {
return $item->ValueType == 'Marital Status';
});
$sexes = $collection->filter(function($item) {
return $item->ValueType == 'Sexes';
});
What this does is, it converts the result array to a Laravel Collection so that you can use the filter function. You can also use array_filter function to filter without converting the result array to a collection.
3) Databases are always one of the primary bottlenecks, the fewer the query number the better. However this should not be a general rule especially when cache is used. And for example making joins or subqueries to reduce the number of queries would be deadly mistake on some cases.
Performance is a huge subject. I'd recommend you to start with the Laravel Debugbar to compare the memory usage, number of queries etc. and investigate more on various techniques including cacheing and design patterns too. Accessing the tables directly within the controller is not a very good idea in the first place...
Yes it does mean that. How big is your Lookups table?
You probably mean $lookups = DB::table('Lookups')->all(); or perhaps consider using an Eloquent model class instead, e.g. $lookups = Lookup::all(); Perhaps you may want to cache the result if the table is small? e.g. use the Cache classes in Laravel.
Better for performance would be to use the cache.
It is belong to your query Data I mean your lookups table data.
You can write the query like this in one time:
$sexes_marital_status= DB::table('Lookups')->where('ValueType', '=', 'Sex')
->orWhere('ValueType' '=', 'Marital Status' )
->get();
return view('clients.edit',compact('client'))
->with('sexes_marital_status',$sexes_marital_status);
and this is better that you send your query in one time.
`
I am trying to fetch Data in a recursive-way (over associations) using CakePHP 3.1
In Cake 3 I can use the "contain" key to fetch the next level of asociated data. But I need to fetch one more level. Does anyone know how to do this? I read the docs but didn't found anything there, with google it's the same.
The 3 Levels are connected like this:
OperationalCostInvoice (belongsTo Object)
-> Object (hasMany OperationalCostTypes)
-> OperationalCostType
With OperationalCostInvoice->get($object_id, ['contain' => 'Object']) I can get the Object that is associated with the OperationalCostInvoice but I also want to fetch the OperationalCostTypes from the Object in (if possible) just one call.
I dont need tipps about association linking the reason that the entities are linked like this is I can easily implement a history function.
Thanks in advance!
I just meant one function call (on the Table object) to fetch everything. I know that more than one query is required.
Just create your own table method then and return all your results in one array or implement whatever you want and return it.
public function foo() {
return [
'one' => $this->find()...->all();
'two' => $this->Asssoc->find()...->all();
];
}
But in CakePHP 2 there was the option recursive which controlled on how many levels associated data is fetched.
The recursive was a pretty stupid thing in Cake2. First thing we've always done was to set it to -1 in the AppModel to avoid unnecessary data fetching. Using contain is always the better choice. I would stay away from using recursive at all, especially for deeper levels.
Also contain is still, as it was in Cake2 as well, able to fetch more than one level deep associations.
$this->find()->contain([
'FirstLevel' => [
'SecondLevel' => [
'ThirdLevel'
]
]
])->all();
1) Is there a way to get the sum of an integer column using CActiveRecord in Yii?
Otherwise I will have to get the column data and sum it up on the server side.
2) I also assume getting the sum via one sql query is faster than getting the column of data and sum it up on the server with php. If performance matters, should the mysql server be bothered to do such operation or just let the php server to take care of this.
Please kindly advice.
1) I don't thinks so, and it doesn't really makes sense to use CAvtiveRecord that way, unless you want to have a STAT relation. Let's say you have a "Question" model and an "Answer" model and the answers belongs to a question. You could make a statistical relation and implement it in "Question" like this:
Public function relations() {
return array(
'answerSum'=>array(self::STAT, 'Answer', 'questionId', 'select' => 'SUM(answerSum.someFieldFromAnswerTableToSum)')
);
}
Then you retrieve the information: $question->answerSum; where $question is an instance of Question with the relations declared as above.
2) It's a matter of the amount of data. I would personally choose SQL, because it is capable of handling a larger amount of datasets and is thereby future-save.
Try it
$user = User::model()->findBySql('select sum(`you_column`) as `sum` from user', array());
var_dump($user->sum);
In model should be present field sum