Using rails 3, How could one do multiple where statements without complicated stuff or extra gems?
Im having this column "accepted" and would like to get all the values where accepted == false and accepted == null
Both of examples below fail:
#scholars = Scholars.where(:scholar_id => current_user.id).where(["accepted = ? or accepted = ?", true, null])
and
#scholars = Scholars.where(:scholar_id => current_user.id).where(:accpeted => true).where(:accepted=> null)
Try:
#scholars = Scholars.where(:scholar => current_user, :accepted => true).all +
Scholar.where(:scholar => current_user, :accepted => nil).all
Did you name your model "Scholars"? Models are traditionally singular... if you named it properly, this should be Scholar.where(...).
The correct answer should be
#profiles = Profile.where(:user_id => current_user.id, :accepted => [true, nil]).order(:accepted)
Can you send more parameters than needed to a prepared statement using PDO with no undesired side effects?
That mights seem like a strange question but I ask because I have 4 queries in a row which all use similar and different parameters. The relevant parts of the queries:
1st (select, different table to others):
WHERE threadID = :tid
2nd (select):
WHERE user_ID = :u_ID AND thread_ID = :tid
3rd (update if 2nd was successful):
SET time = :current_time WHERE user_ID = :u_ID AND thread_ID = :tid
4th (insert if 2nd was unsuccessful):
VALUES (:u_ID, :tid, :current_time)
Can I declare one array with the three parameters at the beginning and use it for all 4 queries?
To sort out any confusion, the queries would be executed seperately. It is the parameters variable being reused and so that would mean some queries would receive parameters they don't need. So something like:
$parameters = array(':tid' => $tid, ':u_ID' => $u_ID, ':current_time' => $time);
$1st = $db->prepare($query1);
$1st->execute($parameters);
$2nd = $db->prepare($query2);
$2nd->execute($parameters);
$3rd = $db->prepare($query3);
$3rd->execute($parameters);
$4th = $db->prepare($query4);
$4th->execute($parameters);
If I can, should I? Will this slow down or cause security flaws to my database or scripts?
If I can make this question a bit clearer, please ask.
Thank you!
Perhaps the documentation has been updated since this question was first asked, but now it is quite clearly stated "No"
You cannot bind more values than specified; if more keys exist in input_parameters than in the SQL specified in the PDO::prepare(), then the statement will fail and an error is emitted.
These answers should be useful in filtering out the extra parameters.
I know this is already answered and it's only asking about whether you can send extra params, but I thought people might arrive at this question, and want to know how to get around this limitation. Here's the solution I use:
$parameters = array('tid' => $tid, 'u_ID' => $u_ID, 'current_time' => $time);
$1st = $db->prepare($query1);
$1st->execute(array_intersect_key($parameters, array_flip(array('tid'))));
$2nd = $db->prepare($query2);
$2nd->execute(array_intersect_key($parameters, array_flip(array('u_ID', 'tid'))));
$3rd = $db->prepare($query3);
$3rd->execute(array_intersect_key($parameters, array_flip(array('u_ID', 'tid', 'current_time'))));
$4th = $db->prepare($query4);
$4th->execute(array_intersect_key($parameters, array_flip(array('u_ID', 'tid', 'current_time'))));
That array_interset_key and array_flip maneuver could be extracted to its own function, like:
function filter_fields($params,$field_names) {
return array_intersect_key($params, array_flip($field_names))
}
I just haven't got around to it yet.
The function flips your array of key names, so you have an array with no values, but the right keys. Then intersect filters the first array so you only have the keys that are in both arrays (in this case, only the ones in your array_flipped array). But you get the values for the original array (not the empties). So you make one array of parameters, but specify which params are actually sent to PDO.
So, with the function, you'd do:
$parameters = array('tid' => $tid, 'u_ID' => $u_ID, 'current_time' => $time);
$1st = $db->prepare($query1);
$1st->execute(filter_fields($parameters, array('tid')));
$2nd = $db->prepare($query2);
$2nd->execute(filter_fields($parameters, array('u_ID', 'tid')));
$3rd = $db->prepare($query3);
$3rd->execute(filter_fields($parameters, array('u_ID', 'tid', 'current_time')));
$4th = $db->prepare($query4);
$4th->execute(filter_fields($parameters, array('u_ID', 'tid', 'current_time')));
If you have PHP 5.4, you can use the square bracket array syntax, to make it even cooler:
$parameters = array('tid' => $tid, 'u_ID' => $u_ID, 'current_time' => $time);
$1st = $db->prepare($query1);
$1st->execute(filter_fields($parameters, ['tid']));
$2nd = $db->prepare($query2);
$2nd->execute(filter_fields($parameters, ['u_ID', 'tid']));
$3rd = $db->prepare($query3);
$3rd->execute(filter_fields($parameters, ['u_ID', 'tid', 'current_time']));
$4th = $db->prepare($query4);
$4th->execute(filter_fields($parameters, ['u_ID', 'tid', 'current_time']));
I got a chance to test my question, and the answer is you cannot send more parameters than the query uses. You get the following error:
PDOException Object
(
[message:protected] => SQLSTATE[HY093]: Invalid parameter number: parameter was not defined
[string:Exception:private] =>
[code:protected] => HY093
[file:protected] => C:\Destination\to\file.php
[line:protected] => line number
[trace:Exception:private] => Array
(
[0] => Array
(
[file] => C:\Destination\to\file.php
[line] => line number
[function] => execute
[class] => PDOStatement
[type] => ->
[args] => Array
(
[0] => Array
(
[:u_ID] => 1
[:tid] => 1
[:current_time] => 1353524522
)
)
)
[1] => Array
(
[file] => C:\Destination\to\file.php
[line] => line number
[function] => function name
[class] => class name
[type] => ->
[args] => Array
(
[0] => SELECT
column
FROM
table
WHERE
user_ID = :u_ID AND
thread_ID = :tid
[1] => Array
(
[:u_ID] => 1
[:tid] => 1
[:current_time] => 1353524522
)
)
)
)
[previous:Exception:private] =>
[errorInfo] => Array
(
[0] => HY093
[1] => 0
)
)
I don't know a huge amount about PDO, hence my question, but I think that because :current_time is sent but not used and the error message is "Invalid parameter number: parameter was not defined" you cannot send extra parameters which are not used.
Additionally the error code HY093 is generated. Now I can't seem to find any documentation explaining PDO codes anywhere, however I came across the following two links specifically about HY093:
What is PDO Error HY093
SQLSTATE[HY093]
It seems HY093 is generated when you incorrectly bind parameters. This must be happening here because I am binding too many parameters.
executing different type of multiple queries with one execute leads to problems. you can run multiple selects or multiple updates with one execute. For this case to create different prepared statements objects and pass the the parameters accordingly.
// for WHERE threadID = :tid
$st1 = $db->prepare($sql);
$st1->bindParam(':tid', $tid);
$st1->execute();
or
$st1->execute(array(':tid'=>$tid);
// for WHERE user_ID = :u_ID AND thread_ID = :tid
$st2 = $db->prepare($sql);
$st2->bindParam(':u_ID', $u_ID);
$st2->bindParam(':tid', $tid);
$st2->execute();
or
$st2->execute(array(':tid'=>$tid, ':u_ID' => $u_ID);
// for SET time = :current_time WHERE user_ID = :u_ID AND thread_ID = :tid
$st3 = $db->prepare($sql);
$st3->bindParam(':u_ID', $u_ID);
$st3->bindParam(':tid', $tid);
$st3->bindParam(':current_time', $current_time);
$st3->execute();
or
$st3->execute(array(':tid'=>$tid, ':u_ID' => $u_ID, ':current_time' => $current_time);
// for VALUES (:u_ID, :tid, :current_time)
$st4 = $db->prepare($sql);
$st4->bindParam(':u_ID', $u_ID);
$st4->bindParam(':tid', $tid);
$st4->bindParam(':current_time', $current_time);
$st4->execute();
or
$st4->execute(array(':tid'=>$tid, ':u_ID' => $u_ID, ':current_time' => $current_time);
I have a nhibernate queryover like this:
var query = Session.QueryOver<Immobile>()
.WhereRestrictionOn(i => i.Agenzia.CodiceAgenzia).IsLike(codiceAgenzia)
.WhereRestrictionOn(i => i.StatoImmobile.StatoImmobileId).IsLike(statoId)
.And(i => i.Prezzo <= prezzo)
.And(i => i.Mq <= metriquadri);
The code compile but on execute I receive this exception:
could not resolve property: Agenzia.CodiceAgenzia of: Domain.Model.Immobile
What am I doing wrong?
QueryOver syntax doesnt work that way unfortunately on Referenced objects you need to join them first and then add the restriction..
Change the code to as follows:
Azengia azengiaAlias=null; //Azengia here is typeof(Immobile.Azengia) I am assuming it is Azengia
StatoImmobile statoImmobileAlias=null; //similarly StatoImmobile is assumed to be typeof(Immobile.StatoImmobile)
var query=Session.QueryOver<Immobile>()
.Where(i => i.Prezzo <= prezzo && i.Mq <= metriquadri)
.Inner.JoinAlias(x=>x.Agenzia,()=>azengiaAlias)
.Inner.JoinAlias(x=>x.StatoImmobile,()=.statoImmobileAlias)
.WhereRestrictionOn(() => azengiaAlias.CodiceAgenzia).IsLike(codiceAgenzia)
.WhereRestrictionOn(() => statoImmobileAlias.StatoImmobileId).IsLike(statoId);
Hope this helps.
I'm trying to load all the collections eagerly, using NHibernate 3 alpha 1. I'm wondering if this the right way of using ThenFetch()?
Properties with plural names are collections. The others are just a single object.
IQueryable<T> milestoneInstances = Db.Find<T, IQueryable<T>>(db =>
from mi in db
where mi.RunDate == runDate
select mi).Fetch(mi => mi.Milestone)
.ThenFetch(m => m.PrimaryOwners)
.Fetch(mi => mi.Milestone)
.ThenFetch(m => m.SecondaryOwners)
.Fetch(mi => mi.Milestone)
.ThenFetch(m => m.Predecessors)
.Fetch(mi => mi.Milestone)
.ThenFetch(m => m.Function)
.Fetch(mi => mi.Milestone)
.ThenFetchMany(m => m.Jobs)
.ThenFetch(j => j.Source)
;
I thought of asking this in the NHibernate forums but unfortunately access to google groups is forbidden from where I am. I know Fabio is here, so maybe the guys from the NHibernate team can shed some light on this?
Thanks
Apparently, there's no "right" way to use ThenFetch in such a case. Your example works fine but SQL produced contains many joins to Milestone, which isn't that right.
Using IQueryOver instead of IQueryable allows you to use complex syntax in Fetch:
Fetch(p => p.B)
Fetch(p => p.B.C) // if B is not a collection ... or
Fetch(p => p.B[0].C) // if B is a collection ... or
Fetch(p => p.B.First().C) // if B is an IEnumerable (using .First() extension method)
So in your case it would be:
query // = session.QueryOver<X>()
.Fetch(mi => mi.Milestone).Eager
.Fetch(mi => mi.Milestone.PrimaryOwners).Eager
.Fetch(mi => mi.Milestone.SecondaryOwners).Eager
.Fetch(mi => mi.Milestone.Predecessors).Eager
.Fetch(mi => mi.Milestone.Function).Eager
.Fetch(mi => mi.Milestone.Jobs).Eager
.Fetch(mi => mi.Milestone.Jobs.First().Source).Eager
The one thing you are missing is that you should use FetchMany() and ThenFetchMany() is the child property is a collection.
IQueryable<T> milestoneInstances = Db.Find<T, IQueryable<T>>(db =>
from mi in db
where mi.RunDate == runDate
select mi);
var fetch = milestoneInstances.Fetch(f => f.Milestone);
fetch.ThenFetch(f => f.PrimaryOwners);
fetch.ThenFetch(f => f.SecondaryOwners);
//...
As leora said, make sure when fetching children collections that you use
FetchMany()
ThenFetchMany()
A new Fetch, should pick up from the root, but this does not always happen. Sometimes you need to create them as separate queries or use Criteria Futures to batch up a multiple fetch.
Now i am inputting some data from a form and i have a code to search the database inputting several parameters as input conditions. Now if one the parameters is null (i.e) the field is unchecked i need to replace that parameter with something say * so that the search query is unaffected. How would i do that?
#report = Problem.find(:all, :conditions => ["problems.cause_id = ? and problems.location_id = ? and problems.device_id = ? and problems.priority_id = ?", Report.find_by_id(params[:id]).cause_id, Report.find_by_id(params[:id]).location_id, Report.find_by_id(params[:id]).device_id, Report.find_by_id(params[:id]).priority_id])
It would be better to not have that condition at all than to use *. In this case it's simple as all of your comparison operators are "=". That means you can use the hash form of conditions. Your code is also quite inefficient as you load the same report object 3 or four times. Your question about one of the params being null doesn't make sense for this reason: you just use the same param again and again. Also you set a variable called #report to be a Problem object which is confusing.
#report = Report.find_by_id(params[:id])
conditions = {:cause_id => #report.cause_id, :location_id => #report.location_id, :device_id => #report.device_id, :priority_id => #report.priority_id}
conditions.delete_if{|k,v| v.blank?}
#problem = Problem.find(:all, :conditions => conditions)
rep = Report.find_by_id(params[:id])
cause = rep.cause_id ? rep.cause_id : '*'
location = rep.location_id ? rep.location_id : '*'
device = rep.device_id ? rep.device_id : '*'
priority = rep.priority_id ? rep.priority_id : '*'
#report = Problem.find(:all,
:conditions => ["problems.cause_id = ? and
problems.location_id = ? and
problems.device_id = ? and
problems.priority_id = ?",
cause, location,
device, priority
]
)