Create Ransack object without querying DB - ruby-on-rails-3

I'd like to be able to create a Ransack::Search object to be passed into a search_form_for, but the initial creation of the search object queries the database, wich I don't want.
I want to show an initial blank form with Ransack::Search options to search, without calling the database.
How can I do that ?
thanks,
regards

Arel relations (ie. queries) are lazily-executed on first reference to the results, so you should find that you can create a search object and pass it to the form, without it calling the db, so long as you don't reference the .result method anywhere.
e.g.
// in your controller
my_query = MyModelClass.where{ id.gt(0) }
#q = my_query.search( params[:q] )
// in your view
search_form_for( #q, (...other options...) )
Any of these will trigger the db query to be actually performed:
- #q.results.each do |result|
- for result in #q.results
- #q.results.count
- #q.results.to_a
- #q.results.size
// ....etc
But so long as you only use the search object for your form, it should not get executed.
Of course, if you're testing this from the console, make sure that you put ;nil at the end of the line, otherwise the console will print the last thing evaluated, which will cause the query to be run!

Related

Rails: How to use instance method in Active Record Query

I am having a filter query which should return all the records where either
attribute (column) "status" is not "done", or
instance method "completeness_status" does not return "done"
The query is something like that:
Studies.where("studies.status != ? OR studies.completeness_status != ?", "done", "done")
but I am getting error that column completeness_status does not exist.
Unfortunately, the column status is not continuously updated, so I cannot use it only. Also, the instance method "completeness_status" is based on records from other tables.
I try to add a scope to my model and use this instance method as scope but also I was not successful.
Also, I tried to used it as class method but then I do not know how to call it from where clause.
def self.completeness_status(study)
# code
end
or
def self.completeness_status_done?(study)
# code return true or false
end
Any Idea how to solve that.
Thanks.
You cannot use instance methods inside your query. But if you like to check the condition of completeness for only one row, then you can use it as instance method:
first_study = Study.first
first_study.completeness_status_done?
Also, if you provide more information about what is going on inside your completeness_status_done? then maybe I can give you some ideas to use scopes.
https://guides.rubyonrails.org/active_record_querying.html

Default values for query parameters

Please forgive me if my question does not make sense.
What im trying to do is to inject in values for query parameters
GET1 File
Scenario:
Given path 'search'
And param filter[id] = id (default value or variable from another feature file)
POST1 File
Scenario:
def newid = new id made by a post call
def checkid = read call(GET1) {id : newid}
like if one of my feature files creates a new id then i want to do a get call with the above scenario. therefore i need a parameter there which takes in the new id.
On the other hand if i do not have an id newly created or the test creating it is not part of the suite. i want to still be able to run the above mentioned scenario but this time it has a default value to it.
Instead of param use params. It is designed so that any keys with null values are ignored.
After the null is set on the first line below, you can make a call to another feature, and overwrite the value of criteria. If it still is null, no params will be set.
* def criteria = null
Given path 'search'
And params { filter: '#(criteria)' }
There are multiple other ways to do this, also refer to this set of examples for data-driven search params: dynamic-params.feature
The doc on conditional logic may also give you some ideas.

passing msqli to a function - can't suss out why it's not working

I've searched high and low for an answer on this, but I'm either missing something, or I just can't find anything in this context.
Background - trying to avoid spaghetti frenzy with a little casual project I'm starting; part of this will involve mainly just calls to a mysql database, displaying table content and so on. Simply put, like a CRM I guess.
I may be way off base here, but I want to be able to create my sql calls as functions, which will help if/when I tweak and tune, as well as creating a cleaner code for what I'm looking to do.
So, without further ado, I have this as a demomstration:
echo "<table>";
selectall('actions','content',$mysqli);
echo "</table><br><br>";
What this does is show all rows from my table of 'actions. "content" is just an example field name I'm passing through that I want to display, as it is the main human-relevant field name in that table. I'm also passing $mysqli through here for my function db call.
My function looks like this:
function selectall($s_table,$s_content,$mysqli){
$query = "SELECT * FROM " . $s_table;
$resource = $mysqli->query($query);
if ( !$resource ) throw new Exception($db->error);
while ( $row = $resource->fetch_assoc() ) {
$id = $row['id'];
echo "<tr><td>{$row[$s_content]}</td></tr>";
}
$resource->free();
$mysqli->close();
}
However.... it doesn't work, and it seems to throw a wobbly saying:
Warning: mysqli::query(): Couldn't fetch mysqli
This points to the action within the line $resource = $mysqli->query($query);
I know the function and everything is ok, as if I restate and declare $mysqli within the first line of the function, like so...
$mysqli = new mysqli(username password and so on in here);
... it works spot on.
$mysqli exists and works within the same code that is passing the variable within the function too.
This is early stages, so by shuffling the code around trying to poke the $mysqli pass into life I have perhaps made the code a little messier that intended, so try not to worry too much about that.
Anyone any ideas why it doesn't like this?
D'oh...
I had a
$mysqli->close();
in the lines above. Solved myself.
For reference, this is my function:
function selectall($s_table,$s_field,$mysqli){
if ($mysqli->connect_error) {die('Connect Error (' . $mysqli->connect_errno . ') '. $mysqli->connect_error);}
$s_table = preg_replace('/[^0-9a-zA-Z_]/', '', $s_table); // Cleans up the table name variable
$s_field = preg_replace('/[^0-9a-zA-Z_]/', '', $s_field); // Cleans up the field name variable
$query = "SELECT * FROM " . $s_table; // Adds passed table name to the select all
$resource = $mysqli->query($query);
if ( !$resource ) throw new Exception($db->error);
while ( $row = $resource->fetch_assoc() ) {
echo "<tr><td>{$row[$s_field]}</td></tr>"; // Content for each row of the select all
}
$resource->free();
$mysqli->close();
}
As you can see, I've also tried to protect the variables that enter the function.
This can be called via:
selectall('actions','content',$mysqli);
In this context, I want to view all the entries in the 'actions' table by the field name 'content'. This function, with some code above and below for a table, will create a new row for each entry.
I'll probably evolve a few, already created on that includes a delete button at the end of the line which is 'selectalldel'.
Open to comments on whether this actually is worthwhile, but thought I'd post up my corrected stupidity in case anyone finds this useful.

How do I get the results of the Plucky Query inside my controller?

I'm missing something simple - I do not want to access the results of this query in a view.
Here is the query:
#adm = Admin.where({:id => {"$ne" => params[:id].to_s},:email => params[:email]})
And of course when you inspect you get:
#adm is #<MongoMapper::Plugins::Querying::DecoratedPluckyQuery:0x007fb4be99acd0>
I understand (from asking the MM guys) why this is the case - they wished to delay the results of the actual query as long as possible, and only get a representation of the query object until we render (in a view!).
But what I'm trying to ascertain in my code is IF one of my params matches or doesn't match the result of my query in the controller so I can either return an error message or proceed.
Normally in a view I'm going to do:
#adm.id
To get the BSON out of this. When you try this on the Decorated Query of course it fails:
NoMethodError (undefined method `id' for #<MongoMapper::Plugins::Querying::DecoratedPluckyQuery:0x007fb4b9e9f118>)
This is because it's not actually a Ruby Object yet, it's still the query proxy.
Now I'm fundamentally missing something because I never read a "getting started with Ruby" guide - I just smashed my way in here and learned through brute-force. So, what method do I call to get the results of the Plucky Query?
The field #adm is set to a query as you've seen. So, to access the results, you'll need to trigger execution of the query. There are a variety of activation methods you can call, including all, first, and last. There's a little documentation here.
In this case, you could do something like:
adm_query = Admin.where({:id => {"$ne" => params[:id].to_s},:email => params[:email]})
#adm_user = adm_query.first
That would return you the first user and after checking for nil
if #adm_user.nil?
# do something if no results were found
end
You could also limit the query results:
adm_query = Admin.where( ... your query ...).limit(1)

Check if an existing value is in a database

I was wondering how I would go about checking to see if a table contains a value in a certain column.
I need to check if the column 'e-mail' contains an e-mail someone is trying to register with, and if something exists, do nothing, however, if nothing exists, insert the data into the database.
All I need to do is check if the e-mail column contains the value the user is registering with.
I'm using the RedBeanPHP ORM, I can do this without using it but I need to use that for program guidelines.
I've tried finding them but if they don't exist it returns an error within the redbean PHP file. Here's the error:Fatal error: Call to a member function find() on a non-object in /home/aeterna/www/user/rb.php on line 2433
Here's the code that I'm using when trying this:
function searchDatabase($email) {
return R::findOne('users', 'email LIKE "' . $email . '"');
}
My approach on the function would be
function searchDatabase($email) {
$data = array('email' => $email);
$user = R::findOne('users', 'email LIKE :email, $data);
if (!empty($user)) {
// do stuff here
} // end if
} // end function
It's a bit more clean and in your function
Seems like you are not connected to a database.
Have you done R::setup() before R::find()?
RedBeanPHP raises this error if it can't find the R::$redbean instance, the facade static functions just route calls to the $redbean object (to hide all object oriented fuzzyness for people who dont like that sort of thing).
However you need to bootstrap the facade using R::setup(). Normally you can start using RB with just two lines:
require('rb.php'); //cant make this any simpler :(
R::setup(); //this could be done in rb.php but people would not like that ;)
//and then go...
R::find( ... );
I recommend to check whether the $redbean object is available or whether for some reason the code flow has skipped the R::setup() boostrap method.
Edited to account for your updated question:
According to the error message, the error is happening inside the function find() in rb.php on line 2433. I'm guessing that rb.php is the RedBean package.
Make sure you've included rb.php in your script and set up your database, according to the instructions in the RedBean Manual.
As a starting point, look at what it's trying to do on line 2433 in rb.php. It appears to be calling a method on an invalid object. Figure out where that object is being created and why it's invalid. Maybe the find function was supplied with bad parameters.
Feel free to update your question by pasting the entirety of the find() function in rb.php and please indicate which line is 2433. If the function is too lengthy, you can paste it on a site like pastebin.com and link to it from here.
Your error sounds like you haven't done R::setup() yet.
My approach to performing the check you want would be something like this:
$count = count(R::find('users', 'email LIKE :email', array(':email' => $email)));
if($count === 0)
{
$user = R::dispense('users');
$user->name = $name;
$user->email = $email;
$user->dob = $dob;
R::store($user);
}
I don't know if it is this basic or not, but with SQL (using PHP for variables), a query could look like
$lookup = 'customerID';
$result = mysql_fetch_array(mysql_query("SELECT columnName IN tableName WHERE id='".$lookup."' LIMIT 1"));
$exists = is_null($result['columnName'])?false:true;
If you're just trying to find a single value in a database, you should always limit your result to 1, that way, if it is found in the first record, your query will stop.
Hope this helps