I have this query in a GET route:
#user = User.where("facebook_id = ?", params[:id].to_i).first
facebook_id is type bigint
and I am feeding it values that I know exist based on printing out all the properties in all my User models. The problem is this query only works on some numbers.
It works for these numbers:
1095512640500310
10155111451974992
10100608785176432
but not for these numbers
10154326172258840
10205871322198368
10153714225855256
Why does this query work for some numbers but not others?
UPDATE:
Here is a screenshot of a different query that prints out facebook_id values:
but this query: #user = User.find_by_facebook_id(10154326172258840)
returns nil for #user
UPDATE
I found that there is a discrepency between the value in the DB and the value that rails prints out. If I print out the facebook_id for this particular user in PG, I see this:
The last digit here is 1 while the last digit in the rails print out is 0.
Why would rails be printing out an incorrect value? Is it rounding for some reason?
I am wondering how I can use where cause with the ActiveRecord find method.
Here is the code I am using:
Supplier.joins(:products).find(params[:id]).where('suppliers.permalink = ? AND variants.master = ?', params[:id], TRUE)
which gives me:
undefined method `where' for #<Supplier:0x007fe49b4eb330>
Supplier.joins(:products).find(params[:id]).where('suppliers.permalink = ? AND variants.master = ?', params[:id], TRUE)
What you're doing here is finding the first record with the id contained in params[:id], then trying to run a where statement on that single record. where only works when run against the model itself.
The confusing part here is that you are using params[:id] both for the primary key (find searches the id field) but then also comparing it to the permalink column in the where clause.
To explain the usage of both methods:
find will search for result(s) from the table, matching the argument you provide it to the id field. You can pass in multiple id's and this method is mostly used to select a row that you know exists, by id. Most commonly it is used with a single id and returns a single instance.
where is used to find all results from the table that match the clause and return a collection of records. You can then refine these results or select one, for example by using .first:
Supplier.joins(:products).where('suppliers.permalink = ? AND variants.master = ?', params[:permalink], true).first
(Note that you're using joins(:products) but then querying variants table. Is this incorrect?)
Supplier.joins(:products).where('suppliers.permalink = ? AND variants.master = ?', params[:id], TRUE).find(params[:id])
I'm trying to learn about SQL injections and have tried to implement these, but when I put this code in my controller:
params[:username] = "johndoe') OR admin = 't' --"
#user_query = User.find(:first, :conditions => "username = '#{params[:username]}'")
I get the following error:
Couldn't find all Users with 'id': (first, {:conditions=>"username = 'johndoe') OR admin = 't' --'"}) (found 0 results, but was looking for 2)
I have created a User Model with the username "johndoe", but I am still getting no proper response. BTW I am using Rails 4.
You're using an ancient Rails syntax. Don't use
find(:first, :condition => <condition>) ...
Instead use
User.where(<condtion>).first
find accepts a list of IDs to lookup records for. You're giving it an ID of :first and an ID of condition: ..., which aren't going to match any records.
User.where(attr1: value, attr2: value2)
or for single items
User.find_by(attr1: value, attr2: value)
Bear in mind that while doing all this, it would be valuable to check what the actual sql statement is by adding "to_sql" to the end of the query method (From what I remember, find_by just does a LIMIT by 1)
I'm trying to do native SQL in Doctrine. Basically I have 2 parameters:
CANDIDATE_ID - user for who we delete entries,
list of FILE_ID to keep
So I make
$this->getEntityManager()->getConnection()->
executeUpdate( "DELETE FROM FILE WHERE CANDIDATE_ID = :ID AND NOT ID IN :KEEPID",
array(
"ID" => $candidate->id,
"KEEPID" => array(2) )
);
But Doctrine fails:
Notice: Array to string conversion in D:\xampp\htdocs\azk\vendor\doctrine\dbal\lib\Doctrine\DBAL\Connection.php on line 786
Is this bug in Doctrine? I'm making somewhere else select with IN but with QueryBuilder and it's working. Maybe someone could suggest better way of deleting entries, with QueryBuilder for example?
$stmt = $conn->executeQuery('SELECT * FROM articles WHERE id IN (?)',
array(array(1, 2, 3, 4, 5, 6)),
array(\Doctrine\DBAL\Connection::PARAM_INT_ARRAY)
);
From Doctrine's documentation.
You can't pass an array of IDs to a parameter. You can do this for scalar values, but even if this had a 'toString', it wouldn't be what you want.
String concatenation is one method,
"DELETE FROM FILE WHERE CANDIDATE_ID = :ID AND NOT ID IN (". implode(",", $list_of_ids) .")"
But this method goes straight around parameters, and therefore suffers in terms of readability, and is limited to a certain maximum line length, which can vary between databases.
Another approach is to write a function returning a table result, which takes a string of IDs as a parameter.
You could also solve this with a join to a table containing the IDs to keep.
It's a problem I've seen many times with few good answers, but it's usually caused by a misunderstanding in the way the database is modelled. This is a 'code smell' for database access.
Per section 2.2 of rails guide on Active Record query interface here:
which seems to indicate that I can pass a string specifying the condition(s), then an array of values that should be substituted at some point while the arel is being built. So I've got a statement that generates my conditions string, which can be a varying number of attributes chained together with either AND or OR between them, and I pass in an array as the second arg to the where method, and I get:
ActiveRecord::PreparedStatementInvalid: wrong number of bind variables (1 for 5)
which leads me to believe I'm doing this incorrectly. However, I'm not finding anything on how to do it correctly. To restate the problem another way, I need to pass in a string to the where method such as "table.attribute = ? AND table.attribute1 = ? OR table.attribute1 = ?" with an unknown number of these conditions anded or ored together, and then pass something, what I thought would be an array as the second argument that would be used to substitute the values in the first argument conditions string. Is this the correct approach, or, I'm just missing some other huge concept somewhere and I'm coming at this all wrong? I'd think that somehow, this has to be possible, short of just generating a raw sql string.
This is actually pretty simple:
Model.where(attribute: [value1,value2])
Sounds like you're doing something like this:
Model.where("attribute = ? OR attribute2 = ?", [value, value])
Whereas you need to do this:
# notice the lack of an array as the last argument
Model.where("attribute = ? OR attribute2 = ?", value, value)
Have a look at http://guides.rubyonrails.org/active_record_querying.html#array-conditions for more details on how this works.
Instead of passing the same parameter multiple times to where() like this
User.where(
"first_name like ? or last_name like ? or city like ?",
"%#{search}%", "%#{search}%", "%#{search}%"
)
you can easily provide a hash
User.where(
"first_name like :search or last_name like :search or city like :search",
{search: "%#{search}%"}
)
that makes your query much more readable for long argument lists.
Sounds like you're doing something like this:
Model.where("attribute = ? OR attribute2 = ?", [value, value])
Whereas you need to do this:
#notice the lack of an array as the last argument
Model.where("attribute = ? OR attribute2 = ?", value, value) Have a
look at
http://guides.rubyonrails.org/active_record_querying.html#array-conditions
for more details on how this works.
Was really close. You can turn an array into a list of arguments with *my_list.
Model.where("id = ? OR id = ?", *["1", "2"])
OR
params = ["1", "2"]
Model.where("id = ? OR id = ?", *params)
Should work
If you want to chain together an open-ended list of conditions (attribute names and values), I would suggest using an arel table.
It's a bit hard to give specifics since your question is so vague, so I'll just explain how to do this for a simple case of a Post model and a few attributes, say title, summary, and user_id (i.e. a user has_many posts).
First, get the arel table for the model:
table = Post.arel_table
Then, start building your predicate (which you will eventually use to create an SQL query):
relation = table[:title].eq("Foo")
relation = relation.or(table[:summary].eq("A post about foo"))
relation = relation.and(table[:user_id].eq(5))
Here, table[:title], table[:summary] and table[:user_id] are representations of columns in the posts table. When you call table[:title].eq("Foo"), you are creating a predicate, roughly equivalent to a find condition (get all rows whose title column equals "Foo"). These predicates can be chained together with and and or.
When your aggregate predicate is ready, you can get the result with:
Post.where(relation)
which will generate the SQL:
SELECT "posts".* FROM "posts"
WHERE (("posts"."title" = "Foo" OR "posts"."summary" = "A post about foo")
AND "posts"."user_id" = 5)
This will get you all posts that have either the title "Foo" or the summary "A post about foo", and which belong to a user with id 5.
Notice the way arel predicates can be endlessly chained together to create more and more complex queries. This means that if you have (say) a hash of attribute/value pairs, and some way of knowing whether to use AND or OR on each of them, you can loop through them one by one and build up your condition:
relation = table[:title].eq("Foo")
hash.each do |attr, value|
relation = relation.and(table[attr].eq(value))
# or relation = relation.or(table[attr].eq(value)) for an OR predicate
end
Post.where(relation)
Aside from the ease of chaining conditions, another advantage of arel tables is that they are independent of database, so you don't have to worry whether your MySQL query will work in PostgreSQL, etc.
Here's a Railscast with more on arel: http://railscasts.com/episodes/215-advanced-queries-in-rails-3?view=asciicast
Hope that helps.
You can use a hash rather than a string. Build up a hash with however many conditions and corresponding values you are going to have and put it into the first argument of the where method.
WRONG
This is what I used to do for some reason.
keys = params[:search].split(',').map!(&:downcase)
# keys are now ['brooklyn', 'queens']
query = 'lower(city) LIKE ?'
if keys.size > 1
# I need something like this depending on number of keys
# 'lower(city) LIKE ? OR lower(city) LIKE ? OR lower(city) LIKE ?'
query_array = []
keys.size.times { query_array << query }
#['lower(city) LIKE ?','lower(city) LIKE ?']
query = query_array.join(' OR ')
# which gives me 'lower(city) LIKE ? OR lower(city) LIKE ?'
end
# now I can query my model
# if keys size is one then keys are just 'brooklyn',
# in this case it is 'brooklyn', 'queens'
# #posts = Post.where('lower(city) LIKE ? OR lower(city) LIKE ?','brooklyn', 'queens' )
#posts = Post.where(query, *keys )
now however - yes - it's very simple. as nfriend21 mentioned
Model.where(attribute: [value1,value2])
does the same thing