Im trying to do something pretty simple in Propel ORM which I just cant seem to work out or find the answer to.
Basically I have a table called post and a table called post_history. Every time someone makes an edit to a post, the previous version is saved to post_history first.
I have an 'undo' button against each post where I simply want to select the last 'post_history' record for the post and revert the post data from the history. To select the last history that is older than my post how do I select GREATER or LESS than in propel?
If I do something like this:
$postHistory = PostHistoryQuery::create()
->filterByPostId($post->getId())
->filterByCreated(array("max" => $post->getUpdated()))
->orderById("DESC")
->limit(1);
the filterByCreated with the 'max' specified does indeed select the last 'post_history' but if you click undo again it selects the same record because the max seems to specify less or equal to rather just less than. It may require a custom query? I think im missing a trick that I cant find the answer too. My search for the answer hasn't helped so far.
Any help is much appreciated.
Ok, so I posted a question on SO for help and within 30 minutes I work it out by just trying things. Typical, eh? It might be useful to someone else so here's what I did:
$postHistory = PostHistoryQuery::create()
->filterByPostId($post->getId())
->filterByCreated(array("max" => $post->getUpdated()))
->orderById("DESC")
->limit(1);
Changed to:
$postHistory = PostHistoryQuery::create()
->filterByPostId($post->getId())
->where('post_history.created < ?', $post->getUpdated())
->orderById("DESC")
->limit(1);
The ->where() clause allows you to specify lots of options e.g >, <, LIKE etc...
Related
I'm trying to sort by the newest messages first, including the sub-messages. For example, if someone adds a sub-comment to an old message at the bottom, it would be moved to the top.
Here is the code I'm using:
$comments = Comment::where('discussion_id' , $info['id'])->where('parent_id', 0)->orderby('id' , 'desc')->paginate(6);
if parent_id is 0, it is not a sub-comment.
It's going to be a bit tricky to produce a query that will work well for you. Especially if you have to support a deeply nested hierarchy of comments (for example comments on Reddit).
Usually comments sections are loaded very often so even if you write this query it will be slow. For that reason, I suggest a solution with an additional table field followed by additional code when you're inserting new comments.
Add a new timestamp field to the comments table and call it touched_on. Every time you insert a new sub-comment update the touched_on of every parent comment in the hierarchy. Now you can edit your code like this:
$comments = Comment::where('discussion_id' , $info['id'])->where('parent_id', 0)->orderBy('touched_on' , 'desc')->paginate(6);
If your comments are not editable then you can even use updated_on column for this but that depends on your requirements.
With this approach, your inserts will be a bit slower but your query for loading comments is super simple and fast. I would take that trade-off any day. Also, if you really need deeply nested comment threads I would look into more robust structures (nested sets maybe) than only using parent_id.
Just order by created_at column.
$comments = Comment::where('discussion_id' , $info['id'])->where('parent_id', 0)->orderby('created_at' , 'desc')->paginate(6);
Disclaimer I'm self taught. Got my rudimentary knowledge of php reading forums. I'm an sql newb, and know next to nothing about yii.
I've got a controller that shows the products on our webstore. I would like the out of stock products to show up on the last pages.
I know I could sort by stock quantity but would like the in stock products to change order every time the page is reloaded.
My solution (probably wrong but kinda works) is to run two queries. One for the product that has stock, sorted randomly. One for the out of stock product also ordered randomly. I then merge the two resulting arrays. This much has worked using the code below (although I feel like there must be a more efficient way than running two queries).
The problem is that this messes up the pagination. Every product returned is listed on the same page and changing pages shows the same results. As far as I can tell the pagination only works for 1 CDbCriteria at a time. I've looked at the yii docs for CPagination for a way around this but am not getting anywhere.
$criteria=new CDbCriteria;
$criteria->alias = 'Product';
$criteria->addCondition('(inventory_avail>0 OR inventoried=0)');
$criteria->addCondition('Product.parent IS NULL');
$criteria->addCondition('web=1');
$criteria->addCondition('current=1');
$criteria->addCondition('sell>sell_web');
$criteria->order = 'RAND()';
$criteria2=new CDbCriteria;
$criteria2->alias = 'Product';
$criteria2->addCondition('(inventory_avail<1 AND inventoried=1)');
$criteria2->addCondition('Product.parent IS NULL');
$criteria2->addCondition('web=1');
$criteria2->addCondition('current=1');
$criteria2->addCondition('sell>sell_web');
$criteria2->order = 'RAND()';
$crit1=Product::model()->findAll($criteria);
$crit2=Product::model()->findAll($criteria2);
$models=array_merge($crit1,$crit2);
//I know there is something wrong here, no idea how to fix it..
$count=Product::model()->count($criteria);
$pages=new CPagination($count);
//results per page
$pages->pageSize=30;
$pages->applyLimit($criteria);
$this->render('index', array(
'models' => $models,
'pages' => $pages
));
Clearly I am in over my head. Any help would be much appreciated.
Edit:
I figured that a third CDbCriteria that includes both the in stock and out of stock items could be used for the pagination (as it would include the same number of products as the combined results of the first 2). So I tried adding this (criteria1 and criteria2 remain the same):
$criteria3=new CDbCriteria;
$criteria3->alias = 'Product';
//$criteria3->addCondition('(inventory_avail>0 OR inventoried=0)');
$criteria3->addCondition('Product.parent IS NULL');
$criteria3->addCondition('web=1');
$criteria3->addCondition('current=1');
$criteria3->addCondition('sell>sell_web');
//$criteria3->order = 'RAND()';
$crit1=Product::model()->findAll($criteria);
$crit2=Product::model()->findAll($criteria2);
$models=array_merge($crit1,$crit2);
$count=Product::model()->count($criteria3);
$pages=new CPagination($count);
//results per page
$pages->pageSize=30;
$pages->applyLimit($criteria3);
$crit1=Product::model()->findAll($criteria);
$crit2=Product::model()->findAll($criteria2);
$models=array_merge($crit1,$crit2);
$this->render('index', array(
'models' => $models,
'pages' => $pages
));
I'm sure I'm missing something super obvious here... Been searching all day getting nowhere.
So you are running into what is IMO one of the potential drawbacks of natural language query builder frameworks. They can get your thinking on how you might approach a SQL problem going down a bad path when trying to work with the "out of the box" methods for building queries. Sometimes you might need to think about using raw SQL query capabilities that most every framework to provide in order to best address your problem.
So let's start with the basic SQL for how I would suggest you approach your problem. You can either work this into your query builder style (if possible) or make a raw query.
You could easily form a calculated field representing binary inventory status for sorting. Then also sort by another criteria secondarily.
SELECT
field1,
field2,
/* other fields */
IF(inventory_avail > 0, 1, 0) AS in_inventory
FROM product
WHERE /* where conditions */
ORDER BY
in_inventory DESC, /* sort items in inventory first */
other_field_to_sort ASC /* other sort criteria */
LIMIT ?, ? /* pagination row limit and offset */
Note that this approach only returns the rows of data you need to display. You move away from your current approach of doing a lot of work in the application to merge record sets and such.
I do question use of RAND() for pagination purposes as doing so will yield products potentially appearing on one page after another as the user paginates through the pages, with other products perhaps not showing up at all. Either that or you need to have some additional complexity added to your applicatoin to somehow track the "randomized" version of the entire result set for each specific user. For this reason, it is really unusual to see order randomization for paginated results display.
I know you mentioned you might like to spike out a randomized view to the user on a "first page". If this is a desire that is OK, but perhaps you decouple or differentiate that specific view from a wider paginated view of the product listing so as to not confuse the end user with a seemingly unpredictable pagination interface.
In your ORDER BY clause, you should always have enough sorting conditions to where the final (most specific) condition will guarantee you a predictable order result. Oftentimes this means you have to include an autoincrementing primary key field, or similar field that provides uniqueness for the row.
So let's say for example I had the ability for user to sort items by price, but you still obviously wanted to show all inventoried items first. Now let's say you have 100K products such that you will have many "pages" of products with a common price when ordered by price
If you used this for ordering:
ORDER BY in_inventory DESC, price ASC
You could still have the problem of a user seeing the same product repeated when navigating between pages, because a more specific criteria than price was not given and ordering beyond that criteria is not guaranteed.
You would probably want to do something like:
ORDER BY in_inventory DESC, price ASC, unique_id ASC
Such that the order is totally predictable (even though the user may not even know there is sorting being applied by unique id).
I make a query (with \yii\db\ActiveQuery) with joins, and some fields in "where" clause become ambigous. Is there a nice and short way to specify the name of the current model`s (ActiveRecord) table (from which one the ActiveQuery was instantiated) before the column name? So I can use this all the time in all cases and to make it short.
Don't like doing smth like this all the time (especially in places where there're no joins, but just to be able to use those methods with joins if it will be needed):
// in the ActiveQuery method initialized from the model with tableName "company"
$this->andWhere(['{{%company}}.`company_id`' => $id]);
To make the "named scopes" to work for some cases with joins..
Also, what does the [[..]] mean in this case, like:
$this->andWhere(['[[company_id]]' => $id]);
Doesn't seem to work like to solve the problem described above.
Thx in advance!
P.S. sorry, don't have enough reputation to create tag yii2-active-query
to get real table name :
Class :
ModelName::getTableSchema()->fullName
Object :
$model::getTableSchema()->fullName
Your problem is a very common one and happens most often with fields liek description, notes and the like.
Solution
Instead of
$this->andWhere(['description'=>$desc]);
you simply write
$this->andWhere(['mytable.description'=>$desc]);
Done! Simply add the table name in front of the field. Both the table name and the field name will be automatically quoted when the raw SQL is created.
Pitfall
The above example solves your problem within query classes. One I struggled over and took me quite some time to solve was a models relations! If you join in other tables during your queries (more than just one) you could also run into this problem because your relation-methods within the model are not qualified.
Example: If you have three tables: student, class, and teacher. Student and teacher probably are in relation with class and both have a FK-field class_id. Now if you go from student via class to teacher ($student->class->teacher). You also get the ambigous-error. The problem here is that you should also qualify your relation definitions within the models!
public function getTeacher()
{
return $this->hasOne(Teacher::className(), ['teacher.id' => 'class.teacher_id']);
}
Proposal
When developing your models and query-classes always fully qualify the fields. You will never ever run into this problem again...that was my experience at least! I actually created my own model-gii-template. So this gets solved automatically now ;)
Hope it helped!
For fun, I'd like to see the set of users (in a Rails database) who were created during a specific hour range (2AM - 5AM to be specific), but on any day. They all have the typical created_at field. I think I know how to extract the hour from this field for one user, and then see if it falls in a range--but how I do do this for all of them? Should I just loop through them? (Even as I write it, that sounds naive).
The first part of Sontyas answer is the easy solution in rails.
I would however move that part to it's own place inside your class to separate your code from the framework a bit more.
# app/models/user.rb
class User < ActiveRecord::Base
# ...
def self.get_users_created_between(start_time, end_time)
User.where("TIME(created_at) BETWEEN TIME(?) AND TIME(?)", start_time, end_time)
end
# ...
end
And use it like this:
irb> User.get_users_created_between(Time.parse("2pm"), Time.parse("5pm"))
This provides you with a couple of benefits:
You can reuse it all over your code without ever having to worry about the syntax of the where or time ranges.
If for some weird reason rails decides to change the interface for this, you only need to edit one method and not code in a thousand places all over your project.
You can easily move this piece of code out of the user.rb if you feel that user.rb gets to big. Maybe to some dedicated finder or query class. Or to something like a repository pattern.
PS: Time functions may vary between different DBMS like MySQL, Postgresql, MSSQL etc. I don't know, if there is generic way to do this. This answer is for MySQL.
Try this,
User.where(created_at: Time.parse("2pm")..Time.parse("5pm"))
Or something like this
User.select { |user| user.created_at.hour.between?(2, 5) }
To return users that where created between two hours on any given day, use this:
User.where('HOUR(created_at) BETWEEN ? AND ?', 2, 5)
Please note that HOUR(created_at) only works for MySQL. The syntax in Postgresql is extract(hour from timestamp created_at) and strftime('%H' created_at) in SQLite.
TL;DR? See Edit 2
I've got a little Rails application that has a few different sort of games people can play: it's based around sports, so they can pick the winners of each game every week (model PickEm, attribute correct boolean with nil for unfinished games), and predict the outcome of a specific team's game (model Guess, attribute score with integer, nil for unfinished games). Every User has_many PickEms and Guesses. And I'm trying to display standings (correct/total - total being all non-nil, score/total possible).
What I'm finding is that I can gather the users and their associated records, but in trying to display standings I'm discovering that every single User is triggering another query - slow and not sustainable as the user base increases. That's because #user.pick_em_score is pick_ems.where(correct: true).size and #user.guess_Score is guesses.where.not(score: nil).sum(:score). So I call user.pick_em_score and it runs that query. I feel like there should be a way to get every User, as well as these specific counts, at once, rather than buffering a whole bunch of needless extra stuff.
What I need:
User record
User.pick_em_score (calculated by counting correct records)
User.pick_ems count where NOT NULL
User.guesses_score (calculated by guesses.sum(:score))
User.guesses count where NOT NULL
Most of the stuff I find on Rails's ActiveRecord helpers, especially related to calculations, is for retrieving only the calculation. It looks like I'll probably need to delve directly into select() etc. But I can't get it working. Can someone point me in the right direction?
Edit
For clarification: I'm aware that I can write this information to the User model, but this is overly restrictive: next season, I'll need to add a new column to the User for that year's results, etc. In addition, this is a third degree of callback updating related models – the Match model already updates related PickEms and Guesses on save. I'm looking for the simplest ActiveRecord query or queries to be able to work with this information, as indicated by the title. Ideally one query that returns the above information, but if it needs to a few, that's OK.
I used to work directly in MySQL with PHP, but those skills have rusted (in raw MySQL, I imagine, I'd have several sub-select statements to help pull these counts) and I'd also like to be able to use Rails's ActiveRecord helpers and such, and avoid constructing raw SQL as much as possible.
Second Edit:
I seem to have it down to one call that starts to work, but I'm writing a lot of SQL. It's also brittle, IMO, and trying to run with it has failed. It also looks like I'm just pushing the million singular SELECT queries from Rails right into SQL, but that may still be a step up.
User.unscoped.select('users.*',
'(SELECT COUNT(*) FROM pick_ems WHERE pick_ems.user_id = users.id AND pick_ems.correct) AS correct_pick_ems',
'(SELECT COUNT(*) FROM pick_ems WHERE pick_ems.user_id = users.id AND pick_ems.correct IS NOT NULL) AS total_pick_ems',
'(SELECT SUM(guesses.score) FROM guesses WHERE guesses.user_id = users.id AND guesses.score IS NOT NULL) AS guesses_score',
'(SELECT COUNT(*) FROM guesses WHERE guesses.user_id = users.id AND guesses.score IS NOT NULL) AS guesses_count' )
The issue seems to be: is there a way to use Rails, and not raw SQL, to link up users.id that we see there with these subqueries? Or just … a better way to construct this, in general?
In addition, I'm running another set of SELECTs for the WHERE, which would hinge on total_pick_ems and guesses_count being > 0 but since I can't use those aliased columns, I have to call the SELECT one more time.
Welcome to AR. Its really only good for simple CRUD like queries. Once you actually want to query your data in anger it just doesn't have the capababilities to do the queries you want without resorting to wholesale SQL strings and often abandoning the ability to chain as a result.
Its precisely why I moved to Sequel as it does have the features to compose queries using a much fuller SQL feature set, including join conditions, window functions, recursive common table expressions, and advanced eager loading. The author is incredibly responsive and documentation is excellent compared to AR and Arel.
I don't expect you will like this answer but a time will come when you will start to look outside the opinionated components that come with rails which I have to say are hardly best of breed. Sequel also sped my application up many times over what I was able to get with AR as well, it not just developer happiness, it means less servers to run. Yes it will be a learning curve but IMO its better to learn tools that have your back covered.
Joins might work. Smthing like below
User.unscoped.joins(:guesses).joins(:pick_ems).
where("guesses.score IS NOT NULL").
select("users.*,
sum(guesses.score) as guesses_score,
count(guesses.id) as guesses_count,
count(case when pick_ems.correct = True then 1 else null end)
as correct_pick_ems,
count(case when pick_ems.correct != null then 1 else null end)
as total_pick_ems,
").
group("users.id")
If you need this information for a limited number of users at a time then above query or eager loading (User.includes(:guesses, :pick_ems)) with class methods like
def correct_pick_ems
pick_ems.count(&:correct)
end
would work.
However If you need this information for all the users most of the time, cached counters within the users table would be more optimal.
What you need is some sort of custom (smart) counter_cache to count only at certain conditions (e.g correct is true)
You can achive this using conditional after_save & after_destroy triggers to build your own custom counter_cache that looks like this:
class PickEm
belongs_to :user
after_save :increment_finished_counter_cache, if: Proc.new { |pick_em| pick_em.correct }
after_destroy :decrement_finished_counter_cache, if: Proc.new { |pick_em| pick_em.correct }
private
def increment_finished_counter_cache
self.user.update_column(:finished_games_counter, self.user.finished_games_counter + 1) #update_column should not trigger any validations or callbacks
end
def decrement_finished_counter_cache
self.user.update_column(:finished_games_counter, self.user.finished_games_counter - 1) #update_column should not trigger any validations or callbacks
end
end
Notes:
Code not tested (only to show the idea)
Some guys said it's better to avoid naming custom counters as rails name them (foo_counter_cache)
You should benchmark it, but my hunch is that adding all of that data into a single SELECT isn't going to be much faster than breaking it up into separate SELECTs (I've actually had cases where the latter was faster). By breaking it up, you can also stick to more ActiveRecord and less raw SQL, e.g.:
user_ids_to_pick_em_score = User.joins(:pick_ems).where(pick_ems: {correct: true}).group(:user_id).count
user_ids_to_pick_ems_count = User.joins(:pick_ems).where.not(pick_ems: {correct: nil}).group(:user_id).count
user_ids_to_guesses_score = Hash[User.select("users.id, SUM(guesses.score) AS total_score").joins(:guesses).group(:user_id).map{|u| [u.id, u.total_score]}]
user_ids_to_guesses_count = User.joins(:guesses).where.not(guesses: {score: nil}).group(:user_id).count
Edit: To display them, you could do like so:
<%- User.select(:id, :name).find_each do |u| -%>
Name: <%= u.name %>
Picks Correct: <%= user_ids_to_pick_em_score[u.id] %>/<%= user_ids_to_pick_ems_count[u.id] %>
Total Score: <%= user_ids_to_guesses_score[u.id] %>/<%= user_ids_to_guesses_count[u.id] %>
<%- end -%>