This has kept me awake until these wee hours.
I want a db to keep track of a soccer tournament.
Each match has two teams, home and away.
Each team can be the home or the away of many matches.
I've got one db, and two document types, "match" (contains: home: teamId and away: teamId) and team (contains: teamId, teamName, etc).
I've managed to write a working view but it would imply adding to each team the id of every match it is involved in, which doesn't make much logical sense - it's such an hack.
Any idea on how this view should be written? I am nearly tempted to just throw the sponge in and use postgres instead.
EDIT: what I want is to have the team info for both the home and away teams, given the id of a match. Pretty easy to do with two calls, but I don't want to make two calls.
Just emit two values in map for each match like this:
function (doc) {
if (!doc.home || !doc.away) return;
emit([doc._id, "home"], { _id: doc.home });
emit([doc._id, "away"], { _id: doc.away });
}
After querying the view for the match id MATCHID with:
curl 'http://localhost:5984/yourdb/_design/yourpp/_view/yourview?startkey=\["MATCHID"\]&endkey=\["MATCHID",\{\}\]&include_docs=true'
you should be able to get both teams' documents in doc fields in list of results (row), possibly like below:
{"total_rows":2,"offset":0,"rows":[
{"id":"MATCHID","key":["MATCHID","home"],"value":{"_id":"first_team_id"},"doc":{...full doc of the first team...}},
{"id":"MATCHID","key":["MATCHID","away"],"value":{"_id":"second_team_id"},"doc":{...full doc of the second team...}}
]}
Check the CouchDB Book: http://guide.couchdb.org/editions/1/en/why.html
It's free and includes answers to a beginner :)
If you like it, consider buying it. Even thought Chris and Jan are so awesome they just put their book out there for free you should still support the great work they did with their book.
Related
i'm trying to get the similarities between one node say me and all the people in the graph not just "friend of friend" which uses the nth order relationship. do i have to go through the whole graph and looping through every user or there's a better way to go?
MATCH (me { name: 'Bradley' })-[:INTEREST]->(stuff)<-
[:INTEREST]-(another_user)
RETURN another_user.name, count(stuff)
ORDER BY count(stuff) DESC
in brief how to replace another_user with all users in the graph in a clean and not costing way
This query should help you:
match (me { name: 'Bradley' })-[:INTEREST]-(stuff) with stuff, collect(stuff) as stuffs match (another_user)-[:INTEREST]-(common_stuff) where common_stuff in stuffs return another_user.name,count(common_stuff) ORDER BY count(common_stuff) DESC
This query will first collect all the items that Bradley is interested in and then iterate through other users and count the items which are common interests between them and Bradley.
I am new to cloudant , no-sql data base (i had worked on mongodb )
1) is there any cloudant ui to write the queires to find the resultset for developing.
2) how to create map-reduce in cloudant ?..
can u please reply me or send your thoughts.
The search indexes are written in JavaScript (at the moment, Cloduant has launched their own "Cloudant Query" which promises to be easier to work with but I haven't had the time to try it properly yet.)
Say you have documents in your DB which contain a field called "UserName" and you want to create a view on all these. You could write a function like this;
function(doc) {
if ( typeof doc.UserName !== "undefined" ) {
emit([doc.UserName], doc._id);
}
}
For example (it will output the user names and document ids)
If a given user name could be associated with multiple documents you could do this, for example;
function(doc) {
if ( typeof doc.UserName !== "undefined" ) {
emit([doc.UserName,doc._id], 1);
}
}
and also use the built-in "count" or "sum" reduce functions that Cloudant provides to tally the number of documents a given user name is associated with etc.
You can use the UI in the Cloudant DB dashboard to execute queries or (as I personally favour) use a tool like Postman (https://www.getpostman.com/)
One word of warning though; error- and sanity -checking of your JavaScript code is pretty much non-existent and you'll only know that something isn't working when you hit "save & build index" which can be a major pain if you're working on large databases (it can grind the whole thing to a halt). A pro tip, therefore, is to work out your indexes on smaller data sets in some safe little sandbox database before you let it lose on anything important...
All of this is supposedly going to be Much Better with Cloudant Query.
I'm very new to CouchDB and I have a simple task that I have no been able to find a straight answer.
I have two related docs: order and invoice
invoice = {
id: "invoice_id",
order: "order_id",
values: [...]
}
order = {
id: "order_id",
**order_number: 12345**
}
I have defined a map function that select the unfulfilled invoices, now I need the order_number, which is in the order doc. They are the same transaction. How do I fetch the order_number from the order when I get my invoices?
I've looked around and I'm getting so many answers like: view collation, linked documents, include_docs=true, structure docs to have both...
I'm just looking for the simplest way with a clear explanation. I appreciate any help.
p.s.
Since I'm new I'm finding couchDB development to be very involved. I have map functions, but they need to be pushed to the couchInstance? Or I edit the map functions in Futon? Are there better ways to develop against couchDB? I see there's couchApp but the docs are sparse and the project hasn't been updated in a while.
I have groups as such:
GroupA
GroupB
Users
GroupG
Users
So the goal is to get all users that are members of parent group GroupA.
I have the following filter:
(&(objectCategory=Person)(objectClass=User)(mail=*MyEmailDomain.com)(memberOf=CN=GroupB,OU=MyOU3,OU=MyOU2,OU=MyOU1,DC=MyDomain,DC=LOCAL))
Which works for the lowest level groups.
From research, it seems that this should work, but doesn't:
(&(objectCategory=Person)(objectClass=User)(mail=*MyEmailDomain.com)(memberof:1.2.840.113556.1.4.1941:=(CN=GroupA,OU=MyOU3,OU=MyOU2,OU=MyOU1,DC=MyDomain,DC=LOCAL)))
If it matters, I'm using Active Directory Explorer to get the Distinguished Names, and the LDAP Input step in Pentaho's Data Integration tool (Kettle/PDI) to retrieve the data.
I love the fact that I always find the answer to my questions as soon as I post them somewhere. I need to learn to post much earlier and maybe I will spend less time searching :)
Found a random stackoverflow post that indicated there's an error in the msdn article for this and it has too many parenthesis.
This won't work:
(&(objectCategory=Person)(objectClass=User)(mail=*MyEmailDomain.com)(memberof:1.2.840.113556.1.4.1941:=(CN=GroupA,OU=MyOU3,OU=MyOU2,OU=MyOU1,DC=MyDomain,DC=LOCAL)))
But this DOES work:
(&(objectCategory=Person)(objectClass=User)(mail=*MyEmailDomain.com)(memberof:1.2.840.113556.1.4.1941:=CN=GroupA,OU=MyOU3,OU=MyOU2,OU=MyOU1,DC=MyDomain,DC=LOCAL))
(no parenthesis around the Distinguished Name)
Hi This does not fetch the users recursively. This is just giving the list of users of parent group only.
(&(objectCategory=Person)(objectClass=User)(mail=*MyEmailDomain.com)(memberof:1.2.840.113556.1.4.1941:=CN=GroupA,OU=MyOU3,OU=MyOU2,OU=MyOU1,DC=MyDomain,DC=LOCAL))
There's a movie which name I can't remember. It's about a carnival or amusement park with a horror house and a bunch of teens who are murdered one by one by something with a clowns mask. I've seen this movie about 20 years ago, and it's sequel, but can't remember it exactly. (And also forgot it's title.) As a result, I started wondering about how to solve something technical.
Assume that I have a database with the story plot and other data of each and every movie published. (Something like the IMDb.) And I would have an edit field where a user can just enter a description in plain text. The system would then start analysing this text to find the movie(s) that would qualify to this description.
For example (different movie), I enter this in the edit field: "Some movie about an Egyptian king who attacks a bunch of indians on horseback, but he's badly wounded and his horse dies while he lost this battle."
The system should then report the movie "Alexander" from 2004 as answer, but possibly a few more. (Even allowing a few errors in the description.)
To create such a system where a description gets analysed to find a matching record by searching through descriptions, what techniques should I need for something as complex as that? Not that I want to build something like that right now, but more out of curiosity if I ever want to pick up some interesting new project.
(I wanted to award extra points for those who recognise the movie I've mentioned in the beginning. But one Google-attempt later and I found it myself!)
Btw, it's not the search engine itself that interests me, but analysing the description to get to something a search engine will understand! With the example movie, it's human logic that helped me to find the title. (And it's annoying that this movie isn't for sale in the Netherlands.) Human logic will always be a requirement but it's about analysing the user input, which is in the form of a story or description, with possible errors.
You should check out document classification.
A few document classification techniques
Naive Bayes classifier
tf–idf
For what I can tell by your own comments, Google is the technique to be used. ;-) But, honestly, I think more or less any search engine would do.
Edit: heh, you removed your comment, but I do remember you mentioned Google as the one deserving extra points.
Edit+: well, you mentioned Google again, but I don't want to remove my first edit. ;-)
Pure speculation: Would something trivial such as taking every word of more than 4 letters in the description "Egyptian, Indian, horse battle etc." and fuzzy matching against a database of such summaries work? Perhaps with some normalisation eg. king == leader == emperor?
Hmmm ... Young Man, Girlfriend, swimming pool, mother, wedding does that get us to The Graduate? Well I guess with a small amount of specifics "Robinson" it might.
You can do lots of interesting stuff with the imdb keyword search:
http://akas.imdb.com/keyword/carnival/clown/murder/
You can specify multiple keywords, it suggests movies and more keywords which are in similar context with your given keywords.
The data contained in imdb is publicy available for non-commercial use and can be downloaded as text files. You could build a database from it.