I have created my first Rails Rake task which imports some data. It uses the URL to identify if the page needs to be updated or inserted. I am however having som really weird issue with some records being inserted multiple times instead, instead of just being updated.
My query looks like this:
existingCompany = Company.find_by_external_link(company.external_link)
I then look at
existingCompany.nil?
to see if the record needs to be created or updated. Some of the companies are not found by active record even though the external link exists. I have tried to print out the url and then look in the database (I use PostgreSQL) and it finds it correctly. The even weirder thing is that it doesn't happen to all records, only a few of them.
Anyone got an idea what might make ActiveRecord believe that a record doesn't exist?
You don't give a lot of information, but a couple of things to try:
How is company.external_link getting set? Either in the debugger or
a simple puts can tell you if it is what you think. For example
"http://www.ups.com/" != "https://www.ups.com/" !=
"http://www.ups.com"
You may need to be consistant on capitalization
or removing white space in company.external_link (.downcase, .strip)
Another thing to keep in mind is ActiveRecord creates a method Company.find_or_create_by_external_link which will do this in one step
Related
I'm querying for test results which are associated with any test set that has a particular tag.
However, this query does not work:
(TestSet.Tags.Name = "foo")
What does work is:
(TestSet.Tags.Name contains "foo")
I would think the first query should work if the second one returns matches with the tag "foo". I presume this is a bug?
I can get around this problem by using the second query, but of course the problem is that this can match a tag named "foo2" as well, so my query can have extra results (potentially many more) and I have to filter them out. Additionally, now I need to have my query fetch the "Tags" as well, so every result I get back is larger because of it.
Yes, as user1195996 suggested this feels like a bug. Your same queries work as expected against defect or user stories. Please work with Rally Support on this issue so we can work to correct it.
I have a User ndb.Model which has a username StringProperty that allows upper en lower case letters, at some point I wanted to fetch users by username but have the case forced to lowercase for the filtering. Therefor I added a ComputedProperty to User: username_lower which returns the lowercase version of the username as follows:
#ndb.ComputedProperty
def username_lower(self):
return self.username.lower()
then I filter the query like so:
query = query.filter(User.username_lower==username_input.lower())
This works, however it only does for users created (put) after I added this to the model. Users created before don't get filtered by this query. I first thought the ComputedProperty wasn't working for the older users. However, tried this and calling .username_lower on an old user does work.
Finally, I found a solution to this is to fetch all users and just run a .put_multi(all_users)
So seems like a ComputedProperty added later to the model works when you invoke it straight but doesn't filter at first. Does it not get indexed automatically ? or could it be a caching thing.. ?
any insight to why it was behaving like this would be welcome
thanks
this is the expected behaviour. The value of a ComputedProperty (or any property for that matter I guess) is indexed when the object is "put". The datastore does not do automatic schema updates or anything like that. When you update your schema you need to either allow for different schema versions in your code or update your entities individually. In the case of changes to indexing you have no choice but to update your entities. The MapReduce API can be used for updating entities to avoid request limitations and the like.
In Rails 3.1, how would you go about making a query string appear cleaner and more readable.
For example, the Rails default for a key with multiple parameters in the query string would appear like:
/clients?ids[]=1&ids[]=2&ids[]=3
I want it to appear like:
/clients?ids=1,2,3
or even
/clients?ids=1|2|3
The ids are controlled by a series of links that act as filters for selecting 1 or more options for filtering on some search results.
What would be the best way to go about this?
The only way you could do it automatically is by monkeypatching something in Rack or Rails. You should avoid doing that as it's going to cause more issues than it solves.
If you have a string that embeds a | or , then you could have it incorrectly converting data. Or if you only have one entry such as ids=1 it wouldn't know to convert it into an array with just 1 inside.
You would be better off doing this manually whenever you need to pass an array that needs to be cleaned up. In this case, you would just call ids.join(",") when passing it to the router method and params[:ids].split(",") to get an array back out.
I'm developing a system (with Rails 2.3.2, Ruby 1.8.7-p72) that has a sizable reporting component. In order to improve performance, I've created a Report model to archive old reports. The idea is that if a matching report already exists for an arbitrary set of conditions then use it, otherwise generate the report and save the results.
Moreover, I'd like to design the Report model in such a way that only the requested attributes have their corresponding SQL queries run. This all stems from the fact that each attribute takes a long time to compute and I'd rather not generate results that won't be used. I.e. I would like to do something like:
def foo
#foo ||= read_attribute(:foo)
if #foo.nil?
#foo = write_attribute(:foo, (expensive SQL query result))
end
#foo
end
The problem I'm experiencing, however, is that results aren't being properly written out to my database and, as a result, the code is constantly reevaluating the SQL query.
Can anyone tell me why write_attribute isn't working? Furthermore, is there a better approach?
Turns out that what I was doing was fine. The real problem was that the object's "id" lookup was being trumped by a piece of code I had elsewhere. I.e. the actual write was occurring to the database, but with the wrong primary key.
Don't you need to call "save" after doing write_attribute?
I have a relatively simple select statement in a VB6 program that I have to maintain. (Suppress your natural tendency to shudder; I inherited the thing, I didn't write it.)
The statement is straightforward (reformatted for clarity):
select distinct
b.ip_address
from
code_table a,
location b
where
a.code_item = b.which_id and
a.location_type_code = '15' and
a.code_status = 'R'
The table in question returns a list of IP addresses from the database. The key column in question is code_status. Some time ago, we realized that one of the IP addresses was no longer valid, so we changed its status to I (invalid) to exclude it from appearing in the query's results.
When you execute the query above in SQL Plus, or in SQL Developer, everything is fine. But when you execute it from VB6, the check against code_status is ignored, and the invalid IP address appears in the result set.
My first guess was that the results were cached somewhere. But, not being an Oracle expert, I have no idea where to look.
This is ancient VB6 code. The SQL is embedded in the application. At the moment, I don't have time to rewrite it as a stored procedure. (I will some day, given the chance.) But, I need to know what would cause this disparity in behavior and how to eliminate it. If it's happening here, it's likely happening somewhere else.
If anyone can suggest a good place to look, I'd be very appreciative.
Some random ideas:
Are you sure you committed the changes that invalidate the ip-address? Can someone else (using another db connection / user) see the changed code_status?
Are you sure that the results are not modified after they are returned from the database?
Are you sure that you are using the "same" database connection in SQLPlus as in the code (database, user etc.)?
Are you sure that that is indeed the SQL sent to the database? (You may check by tracing on the Oracle server or by debugging the VB code). Reformatting may have changed "something".
Off the top of my head I can't think of any "caching" that might "re-insert" the unwanted ip. Hope something from the above gives you some ideas on where to look at.
In addition to the suggestions that IronGoofy has made, have you tried swapping round the last two clauses?
where
a.code_item = b.wich_id and
a.code_status = 'R' and
a.location_type_code = '15'
If you get a different set of results then this might point to some sort of wrangling going on that results in dodgy SQL actually be sent to the database.
There are Oracle bugs that result in incorrect answers. This surely isn't one of those times. Usually they involve some bizarre combination of views and functions and dblinks and lunar phases...
It's not cached anywhere. Oracle doesn't cache results until 11 and even then it knows to change the cache when the answer may change.
I would guess this is a data issue. You have a DISTINCT on the IP address in the query, why? If there's no unique constraint, there may be more than one copy of your IP address and you only fixed one of them.
And your Code_status is in a completely different table from your IP addresses. You set the status to "I" in the code table and you get the list of IPs from the Location table.
Stop thinking zebras and start thinking horses. This is almost certainly just data you do not fully understand.
Run this
select
a.location_type_code,
a.code_status
from
code_table a,
location b
where
a.code_item = b.which_id and
b.ip_address = <the one you think you fixed>
I bet you get one row with an 'I' and another row with an 'R'
I'd suggest you have a look at the V$SQL system view to confirm that the query you believe the VB6 code is running is actually the query it is running.
Something along the lines of
select sql_text, fetches
where sql_text like '%ip_address%'
Verify that the SQL_TEXT is the one you expect and that the FETCHES count goes up as you execute the code.