I have a model called Shops with an attribute called brands, brands is a text field and contains multiple brands. What i would like to do is select all unique brands and display them sorted in alphabetic order
#brands = Shop.all(:select => 'distinct(brands)')
What to do from here?
If Shop#brands can hold multiple values like for example: "rony, hoke, fike", then I can reluctantly suggest doing something like this:
#brands = Shop.all(:select => 'brands').each { |s|
s.brands.split(',').map { |b|
b.strip.downcase
}
}.flatten.uniq.sort
BUT, you should really think about your data model here to prevent such hackery. You couuld break out the brands into it's own table + model and do a many to many relationship with Shop.
Related
I have following SQL Query:
SELECT campaigns.* , campaign_countries.points, offers.image
FROM campaigns
JOIN campaign_countries ON campaigns.id = campaign_countries.campaign_id
JOIN countries ON campaign_countries.country_id = countries.id
JOIN offers ON campaigns.offer_id = offers.id
WHERE countries.code = 'US'
This works perfectly well. I want its rails active record version some thing like:
Campaign.includes(campaign_countries: :country).where(countries: {code: "US"})
Above code runs more or less correct query (did not try to include offers table), issue is returned result is collection of Campaign objects so obviously it does not include Points
My tables are:
campaigns --HAS_MANY--< campaign_countries --BELONGS_TO--< countries
campaigns --BELONGS_TO--> offers
Any suggestions to write AR version of this SQL? I don't want to use SQL statement in my code.
I some how got this working without SQL but surely its poor man's solution:
in my controller I have:
campaigns = Campaign.includes(campaign_countries: :country).where(countries: {code: country.to_s})
render :json => campaigns.to_json(:country => country)
in campaign model:
def points_for_country country
CampaignCountry.joins(:campaign, :country).where(countries: {code: country}, campaigns: {id: self.id}).first
end
def as_json options={}
json = {
id: id,
cid: cid,
name: name,
offer: offer,
points_details: options[:country] ? points_for_country(options[:country]) : ""
}
end
and in campaign_countries model:
def as_json options={}
json = {
face_value: face_value,
actual_value: actual_value,
points: points
}
end
Why this is not good solution? because it invokes too many queries:
1. It invokes query when first join is performed to get list of campaigns specific to country
2. For each campaign found in first query it will invoke one more query on campaign_countries table to get Points for that campaign and country.
This is bad, Bad and BAD solution. Any suggestions to improve this?
If You have campaign, You can use campaign.campaign_countries to get associated campaign_countries and just get points from them.
> campaign.campaign_countries.map(&:points)
=> [1,2,3,4,5]
Similarly You will be able to get image from offers relation.
EDIT:
Ok, I guess now I know what's going on. You can use joins with select to get object with attached fields from join tables.
cs = Campaign.joins(campaign_countries: :country).joins(:offers).select('campaigns.*, campaign_countries.points, offers.image').where(countries: {code: "US"})
You can than reference additional fields by their name on Campaign object
cs.first.points
cs.first.image
But be sure, that additional column names do not overlap with some primary table fields or object methods.
EDIT 2:
After some more research I came to conclusion that my first version was actually correct for this case. I will use my own console as example.
> u = User.includes(:orders => :cart).where(:carts => { :id => [5168, 5167] }).first
> u.orders.length # no query is performed
=> 2
> u.orders.count # count query is performed
=> 5
So when You use includes with condition on country, in campaign_countries are stored only campaign_countries that fulfill Your condition.
Try this:
Campaign.joins( [{ :campaign_countries => :countries}, :offers]).where('`countries`.`code` = ?', "US")
DB table:
Mcourse(Master course )-> contains Course Names
Lcourse(Linked
Course- courses belongs to a college) -> contains foreign key
Mcourse_Id. & college Id.
Nw the problem is
I want to display list of courses available in a college using dropdownlist.
So sql query is:
select Lcourse_Id, Mcourse_Name* from Lcourse inner join Mcourse on Lcourse_Mcourse_Id=Mcourse Id..
*Id & value pair for dropdownlist
I could do this usin createCommand..Its working pretty fine. But i cant do this usin Relations ..Help me.
Let's imagine for a minute that your Mcourse table is called courses and model for that table is called Courses, your Lcourse table is called courses_colleges and your colleges table is colleges and model for that table is Colleges
Now, You should have Courses model with relations:
public function relations() {
return array(
'colleges' => array(self::MANY_MANY, 'Colleges', 'courses_colleges(course_id, college_id)')
);
}
Your Colleges model should have similar relations:
public function relations() {
return array(
'courses' => array(self::MANY_MANY, 'Courses', 'courses_colleges(college_id, course_id)')
);
}
Now if you want to print out a dropdown with all courses available for a certain college. In your controller action method get the model of that college including its courses:
public function actionShow() {
$id = 1; // We set just some sample id. You could get it from request ofc.
$college = Colleges::model()->with('courses')->findByPk($id);
$this->render('show', array('college'=>$college));
}
Now in your view print out this:
echo CHtml::dropDownList('courses', '', CHtml::listData($college->courses, 'id', 'name'));
Where 'id' and 'name' are columns of your Courses model.
Something like that.
The error is in the listData() function in your view, specifically that you don't have a mc_Id in your Lcourse model.
As you haven't clarified the model that each of those relationships are assigned with, it's impossible to guess what you should substitute for 'mc_Id' in your view - check your Lcourse model to determine the proper column name.
I'm working on developing a category roll-up report for a Magento (1.6) store.
To that end, I want to get an Order Item collection for a subset of products - those product whose unique category id (that's a Magento product attribute that I created) match a particular value.
I can get the relevant result set by basing the collection on catalog/product.
$collection = Mage::getModel('catalog/product')
->getCollection()
->addAttributeToFilter('unique_category_id', '75')
->joinTable('sales/order_item', 'product_id=entity_id', array('price'=>'price','qty_ordered' => 'qty_ordered'));
Magento doesn't like it, since there are duplicate entries for the same product id.
How do I craft the code to get this result set based on Order Items? Joining in the product collection filtered by an attribute is eluding me. This code isn't doing the trick, since it assumes that attribute is on the Order Item, and not the Product.
$collection = Mage::getModel('sales/order_item')
->getCollection()
->join('catalog/product', 'entity_id=product_id')
->addAttributeToFilter('unique_category_id', '75');
Any help is appreciated.
The only way to make cross entity selects work cleanly and efficiently is by building the SQL with the collections select object.
$attributeCode = 'unique_category_id';
$alias = $attributeCode.'_table';
$attribute = Mage::getSingleton('eav/config')
->getAttribute(Mage_Catalog_Model_Product::ENTITY, $attributeCode);
$collection = Mage::getResourceModel('sales/order_item_collection');
$select = $collection->getSelect()->join(
array($alias => $attribute->getBackendTable()),
"main_table.product_id = $alias.entity_id AND $alias.attribute_id={$attribute->getId()}",
array($attributeCode => 'value')
)
->where("$alias.value=?", 75);
This works quite well for me. I tend to skip going the full way of joining the eav_entity_type table, then eav_attribute, then the value table etc for performance reasons. Since the attribute_id is entity specific, that is all that is needed.
Depending on the scope of your attribute you might need to add in the store id, too.
I want to join records together and separate them with "-"
I know how to join one table records together like this:
#keywords = #tweet.hash_tags.join("-")
But what if it's HABTM associated tables.
For example.
// BRAND MODEL
has_and_belongs_to_many :categories
// CATEGORY MODEL
has_and_belongs_to_many :brands
If I do this:
#brands = Brand.all
#brand_categories = #brands.categories.join("-")
I get this result:
#<Category:0x0000010445c928>,#<Category:0x0000010445c7c0>,#<Category:0x0000010445c5e0>,#<Category:0x0000010445c400>,#<Category:0x0000010445c270>
Hope you understand my question - thanks.
#join will call #to_s on the items in the Array returned by #brands.categories by default, and it doesn't look like you've defined a custom Category#to_s. Either do so, or be more explicit about the string representation you want; if, for example, a Category has a title attribute, you could use:
#brands_categories = #brands.categories.map(&:title).join("-")
Assuming your Category table has a name field:
#brand_categories = #brands.categories.collect(&:name).join("-")
This will put all of the name values into an array, and then join those.
Sorry to ask all these questions about Kohana. They usually get ignored. I think I just found a bug. I'm making a join between two tables that are not directly related.
$results = ORM::factory('foo')->join("bar")->on("foo.foreign_id", "=", "bar.id");
This generates a query that does not resolve the table names explicitly:
SELECT * FROM `foo` JOIN `bar` ON (`foo`.`foreign_id` = `bar`.`id`)
Which gives (in phpMyAdmin) a table that looks like this:
id time foreign_id blah_int id baz
4 1291851245 3 0 3 52501504
Notice there are two id columns, one for the foo table and one for bar. This is a real problem. Because now, in my results, if I loop through...
foreach ($results as $result) {
echo $result->id; // prints 3!!!
}
Because my results should be foo objects, I expect to get an id of 4, but it's giving me 3 because of the join. Is this a bug in the ORM library? Should I be using a different method to restrict my results from the query? I really don't want to do two separate queries where I load all the bars id's, and then load my foos that way, but it looks like I have to.
You have to use the Database object to build raw queries, not ORM, like this:
$results = DB::select()->from('foo')->join('bar')->on("foo.foreign_id", "=", "bar.id")->execute();
You will need to specific some column aliases however to make your query work unless you use ORM as it was intended.
Using ORM
If you want to use ORM, you need to define the relationships in your model. You mention that they share a relationship with another table so in your case you could use a has many through relationship like this:
protected $_has_many = array(
'bars' => array('model' => 'bar', 'through' => 'other_table', 'foreign_key' => 'foreign_id'),
);
Although your example as given suggests that a straight has_many relationship would work:
protected $_has_many = array(
'bars' => array('model' => 'bar','foreign_key' => 'foreign_id'),
);
This would allow you to access all of the bars using a statement like
$bars = $results->bars->find_all();
foreach($bars as $bar)
{
echo $bar->id; // should echo 4, assuming one record in bars with id 4
}
The Kohana 3.1 ORM Reference Guide is good place to start if you want to learn more about ORM and relationships
Using the Kohana database object and query builder
If you prefer ad hoc queries and are doing joins using the query builder you will likely have colliding column names regardless if you are using Kohana or just raw queries (pop "SELECT * FROM foo JOIN bar ON (foo.foreign_id = bar.id)" into MySQL and you will get the exact same result).
Kohana, just like MySQL allows you to define column aliases for precisely this reason. (See here for more information)
Rewrite your query as follows:
$results = DB::select('id', 'time', 'foreign_id', array('bar.id', 'bar_id'), 'baz')->from('foo')->join("bar")->on("foo.foreign_id", "=", "bar.id")->execute();
This will return:
id time foreign_id blah_int bar_id baz
4 1291851245 3 0 3 52501504