I'm using Rails with ActiveAdmin gem. And I want to select some information from mysql database.
sql = ActiveRecord::Base.connection();
s="SELECT word FROM dics WHERE word LIKE 'tung%'";
ten = sql.execute(s);
But when I printed out "ten" to screen, it showed that:
#<Mysql2::Result:0x4936260>
How can I get the information of records?
I suggest that you don't use ActiveRecord::Base.connection directly. Sticking with ARel syntax should work for most cases, and your example doesn't seem like an edge case.
As stated in the comments above, try the following:
dics = Dic.select(:word).where(["word LIKE ?", "tung%"]).all
In order to pluck some special field of object, not objects themselves, use pluck instead of all:
# instead of .pluck(:word) use real field identifier
dics = Dic.where(["word LIKE ?", "tung%"]).pluck(:word)
Related
Setup:
I'm using Ruby on Rails with ActiveRecord and MySQL.
I have a Coupon model.
It has an attribute called query, it is a string which could be run with a where.
For example:
#coupon.query
=> "'http://localhost:3003/hats' = :url OR 'http://localhost:3003/shoes' = :url"`
If I were to run this query it would either pass or fail based on the :url value I pass in.
# passes
Coupon.where(#coupon.query, url: 'http://localhost:3003/hats')
Coupon.where(#coupon.query, url: 'http://localhost:3003/shoes')
# fails
Coupon.where(#coupon.query, url: 'http://localhost:3003/some_other_url')
This query varies between Coupon models, but it will always be compared to the current url.
I need a way to say: Given an ActiveRecord collection #coupons only keep coupons with queries that pass.
The structure of the where is always the same, but the query changes.
Is there any way to do this without a loop? I could potentially have a lot of coupons and I am hoping to do this an ActiveRecord scope. Something like this?
#coupons.where(self.query, url: #url)
Perhaps I need to write a user defined function in my database?
Using multiple variables in a query is easy, but where the thing you are comparing your variable to is also a variable - that has me stumped. Any suggestions very appreciated.
I would agree with Les Nightingill's comment that this looks like something that should probably be solved at a more architectural level. I'd imagine an easy refactoring to extract a new CouponQuery model that's a 1:n table containing multiple entries for a coupon_id for each query url that should pass. Then you could use a simple join like
Coupon.joins(:coupon_query).where(coupon_queries: { url: my_url })
If adding a new table is not an option, and if you're running on a newer MySQL version (>= 5.7), you could consider transforming the query column (or adding a new json_query column) into a MySQL JSON field and using the new JSON_CONTAINS query.
If from the user-side they should be able to manage the queries as a plain text field, you could use a before_save hook on your model to translate this into the separate table structure or JSON format respectively.
But if neither is an option for you and you really need to stick with the query column that stores a plain string, then you could use a LIKE query to match the sub-string 'your-url' = :url:
Coupon.where('url LIKE "%? = :url%"', my_url)
which, if you e.g. pass 'http://localhost:3003/hats' as my_url would return something like this SQL query:
SELECT `coupons`.* FROM `coupons`
WHERE (url LIKE "%'http://localhost:3003/hats' = :url%")
I have a database entry that looks like the following:
name = servername\vs1
We have a search that is looking for this term.
scope :search, ->(term) {
if term
where('name LIKE ?', "%#{term}%")
else
all
end
}
However, it isn't finding it. When someone searches for severname, of course, it shows up. But when they include the backslash it isn't found.
After doing some research, I found that rails is currently adding a single backslash to the query term prior to search (servername\\vs1) but mysql needs the following format: (servername\\\\vs1).
So, I was hoping there was an easy rails way to add additional backslashes. Looking for any good solution.
Thanks
Easiest to use Arel, like this:
scope :search, ->(term){
t = arel_table
term ? where( t[:name].matches("%#{term}%") )
: all
}
Example:
Simple.search('\a').to_sql
"SELECT \"simples\".* FROM \"posts\" WHERE (\"simples\".\"title\" LIKE '%\\a%')"
I am working on a problem where I need to add an OR clause to a set of existing conditions. The current conditions are built in a hash in a method and at the end, they are used in the where clause. Here is a simplified example:
...
conds.merge!({:users => {:archived => false}})
Model.where(conds)
I am trying to add an OR clause to the current set of conditions so it would be something like '(conditions) OR new_condition'. I'd like to add the OR statement without converting each addition to the conds hash into a string. That would be my last option. I was hoping someone has done something like this before (without using Arel). I seem to recall in Rails 2 there was a way to parse a conditions hash using a method from the model (something like Model.some_method(conds) would produce the where clause string. Maybe that would be a good option to just add the OR clause on to that string. Any ideas are appreciated. Thank you for your help!
I found a way to do what I needed. Instead of changing all of the conditions that I am building, I am parsing the conditions to SQL using sanitize_sql_for_conditions. This is a private method in ActiveRecord, so I had to put a method on the model to allow me to access it. Here is my model method:
def self.convert_conditions_hash_to_sql(conditions)
self.sanitize_sql_for_conditions(conditions)
end
So, once I convert my conditions to text, I can add my OR clause (along with the appropriate parentheses) to the end of the original conditions. So, it would go something like this:
Model.where('(?) OR (model.type = ? AND model.id IN(?))', Model.convert_conditions_hash_to_sql(conds), model_type, model_id_array)
I'm using Rails 3 with a MySQL database, and I need to programmatically create a query like this:
select * from table where category_name like '%category_name_1%'
OR category_name like '%category_name_2%'
(...snip...)
OR category_name like '%category_name_n%'
Given the table size and the project scope (500 rows at most, I think), I feel that using something like thinking sphinx would be overkill.
I know I could simply do this by writing the query string directly, but wanted to know if there's an ActiveRecord way to do this. There's no mention of this on the official guide, and I've been googling for a long while now, just to end empty-handed :(
Also, is there a reason (maybe a Rails reason?) to not to include the OR clause?
Thanks!
Assuming you have an array names with category names:
Model.where( names.map{"category_name LIKE ?"}.join(" OR "),
*names.map{|n| "%#{n}%" } )
you should google first, there is already an answer.
Look here and then here
and you'll get something like this:
accounts = Account.arel_table
Account.where(accounts[:name].matches("%#{user_name}%").or(accounts[:name].matches("%#{user_name2}%")))
If you look at the guide, they have examples that can easily be modified to this:
Client.where("orders_count = ? OR locked = ?", params[:orders], false)
Mysql has a regexp function now that can clean things up a bit, assuming there's no regex metachars in your category names:
Table.where "category_name regexp '#{names.join('|')}'"
I'm trying to accomplish a multiple word searching in a quotes database using Ruby, ActiveRecord, and MySQL. The way I did is shown bellow, and it is working, but I would like to know if there a better way to do.
# receives a string, splits it in a array of words, create the 'conditions'
# query, and send it to ActiveRecord
def search
query = params[:query].strip.split if params[:query]
like = "quote LIKE "
conditions = ""
query.each do |word|
conditions += (like + "'%#{word}%'")
conditions += " AND " unless query.last == word
end
#quotes = Quote.all(:conditions => conditions)
end
I would like to know if there is better way to compose this 'conditions' string. I also tried it using string interpolation, e.g., using the * operator, but ended up needing more string processing. Thanks in advance
First, I strongly encourage you to move Model's logic into Models. Instead of creating the search logic into the Controller, create a #search method into your Quote mode.
class Quote
def self.search(query)
...
end
end
and your controller becomes
# receives a string, splits it in a array of words, create the 'conditions'
# query, and send it to ActiveRecord
def search
#quotes = Quote.search(params[:query])
end
Now, back to the original problem. Your existing search logic does a very bad mistake: it directly interpolates value opening your code to SQL injection. Assuming you use Rails 3 you can take advantage of the new #where syntax.
class Quote
def self.search(query)
words = query.to_s.strip.split
words.inject(scoped) do |combined_scope, word|
combined_scope.where("quote LIKE ?", "%#{word}%")
end
end
end
It's a little bit of advanced topic. I you want to understand what the combined_scope + inject does, I recommend you to read the article The Skinny on Scopes.
MySQL fulltext search not working, so best way to do this:
class Quote
def self.search_by_quote(query)
words = query.to_s.strip.split
words.map! { |word| "quote LIKE '%#{word}%'" }
sql = words.join(" AND ")
self.where(sql)
end
end
The better way to do it would be to implement full text searching. You can do this in MySQL but I would highly recommend Solr. There are many resources online for implementing Solr within rails but I would recommend Sunspot as an entrance point.
Create a FULLTEXT index in MySQL. With that, you can leave string processing to MySQL.
Example : http://dev.mysql.com/doc/refman/5.0/en/fulltext-search.html