What is the best strategy for selecting mongodb entries in which a string value contains a set of words or phrases? I'm thinking of something equivalent to mysql's LIKE function, e.g.
WHERE (TEXT LIKE "% apple %") or (TEXT LIKE "% banana %")
I've seen options that involve tokenizing the string, but this would involve building unigrams for all the text, which would be huge no?
Mongo now supports text search since 2.4.
My experience has been pretty positive
http://docs.mongodb.org/manual/applications/text-search/
You start the server with setParameter text search enabled
Then enable the index on the collection
Then search with runCommand
MongoDB has no full text search capability right now, but it's easy to use external search engines like SOLR.
I strongly discourage you trying to rebuild text search with Regex or word stemming etc. yourself. You should rather focus on your app own features :)
I am using this combination: Mongoid, Sunspot and Mongoid-Sunspot. It works very well in production, and development setup is easy.
You can use the regular expression support in MongoDB queries. More details available # the following link
http://docs.mongodb.org/manual/reference/operator/regex/
Here are two examples should the above link move again in the future:
db.collection.find( { field: /acme.*corp/i } );
db.collection.find( { field: { $regex: 'acme.*corp', $options: 'i' } } );
Somehow MongoDB built-in text search failed to meet my requirements on an existing database which used a compound index. I am now using mongoose-search-plugin and it has been working superbly well. It uses natural stemming, and distance algorithms to return a relevance score.
User.search('Malaysia Car Food',{username:1},{}, function(err, u){
console.log('Search Results: '+JSON.stringify(u));
});
Related
I'm writing a UI that presents the results of a MongoDB full text search query, visually highlighting the matched search terms in each result; this works well enough for full word or phrase matches, but not for partial/fuzzy matches.
For example, if I search for "delete" a will get a search result that contains "deletion", which does not contain the full word "delete" and therefore won't be highlighted if I merely highlight the full search term matches. I do want the partial matches, though.
Is there any way to project the set of matched words/substrings when I execute the query?
I've so far been unable to find anything in the docs that hints at this being possible, but I thought it worth asking around. Any help would be greatly appreciated.
You can use the Mongo DB Atlas feature where you can search your text based on different Analyzers that MongoDB provides. And you can then do a search like this: Without the fuzzy object, it would do a full-text-match search.
$search:{
{
index: 'analyzer_name_created_from_atlas_search',
text: {
query: 'Text to do a full match or fuzzy match with',
path: 'sentence',
fuzzy:{
maxEdits: 2 #max 2 is allowed
}
}
}
}
I'm currently having some issues with the full text search functionality in MongoDB with or condition. Specifically when trying to match exact phrases with or condition.
Exact Phrase and or condition Not working properly in mongodb full text search
{
$text: { $search: "cake \"coffee shop\"" }
}
i want result which find all documents containing “cake” or “coffee shop”:
Have a look here.
If the search string includes phrases, the search performs an AND with any other terms in the search string; e.g. search for "\"twinkle twinkle\" little star" searches for "twinkle twinkle" and ("little" or "star").
My application has the following stack:
Sinatra on Ruby -> MongoMapper -> MongoDB
The application puts several entries in the database. In order to crosslink to other pages, I've added some sort of syntax. e.g.:
Coffee is a black, caffeinated liquid made from beans. {Tea} is made from leaves. Both drinks are sometimes enjoyed with {milk}
In this example {Tea} will link to another DB entry about tea.
I'm trying to query my mongoDB about all 'linked terms'. Usually in ruby I would do something like this: /{([a-zA-Z0-9])+}/ where the () will return a matched string. In mongo however I get the whole record.
How can I get mongo to return me only the matched parts of the record I'm looking for. So for the example above it would return:
["Tea", "milk"]
I'm trying to avoid pulling the entire record into Ruby and processing them there
I don't know if I understand.
db.yourColl.aggregate([
{
$match:{"yourKey":{$regex:'[a-zA-Z0-9]', "$options" : "i"}}
},
{
$group:{
_id:null,
tot:{$push:"$yourKey"}
}
}])
If you don't want to have duplicate in totuse $addToSet
The way I solved this problem is using the string aggregation commands to extract the StartingIndexCP, ending indexCP and substrCP commands to extract the string I wanted. Since you could have multiple of these {} you need to have a projection to identify these CP indices in one shot and have another projection to extract the words you need. Hope this helps.
I have a Mongo search set up that goes through my entries based on numerous criteria.
Currently the easiest way (I know it's not performance-friendly due to using wildcards, but I can't figure out a better way to do this due to case insensitivity and users not putting in whole words) is to use regex wildcards in the search. The search ends up looking like this:
{ gender: /Womens/i, designer: /Voodoo Girl/i } // Should return ~200 results
{ gender: /Mens/i, designer: /Voodoo Girl/i } // Should return 0 results
In the example above, both searches are returning ~200 results ("Voodoo Girl" is a womenswear label and all corresponding entries have a gender: "Womens" field.). Bizarrely, when I do other searches, like:
{ designer: /Voodoo Girl/i, store: /Store XYZ/i } // should return 0 results
I get the correct number of results (0). Is this an order thing? How can I ensure that my search only returns results that match all of my wildcarded queries?
For reference, the queries are being made in nodeJS through a simple db.products.find({criteria}) lookup.
To answer the aside real fast, something like ElasticSearch is a wonderful way to get more powerful, performant searching capabilities in your app.
Now, the reason that your searches are returning results is that "mens" is a substring of "womens"! You probably want either /^Mens/i and /^Womens/i (if Mens starts the gender field), or /\bMens\b/ if it can appear in the middle of the field. The first form will only match the given field from the beginning of the string, while the second form looks for the given word surrounded by word boundaries (that is, not as a substring of another word).
If you can use the /^Mens/ form (note the lack of the /i), it's advisable, as anchored case-sensitive regex queries can use indexes, while other regex forms cannot.
$regex can only use an index efficiently when the regular expression has an anchor for the beginning (i.e. ^) of a string and is a case-sensitive match.
I want to be able to search for my objects by searching for the last 4 characters of the id. How can I do that?
Book.where(_id: params[:q])
Where the param would be something like a3f4, and in this case the actual id for the object that I want to be found would be:
bc313c1f5053b66121a8a3f4
Notice the last for characters are what we searched for. How can I search for just "part" of my objects id? instead of having my user search manually by typing in the entire id?
I found in MongoDB's help docs, that I can provide a regex:
db.x.find({someId : {$regex : "123\\[456\\]"}}) // use "\\" to escape
Is there a way for me to search using the regular mongo ruby driver and not using Mongoid?
Usually, in Mongoid you can search with a regexp like you normally would with a string in your call to where() ie:
Book.where(:title => /^Alice/) # returns all books with titles starting with 'Alice'
However this doesn't work in your case, because the _id field is not stored as a string, but as an ObjectID. However, you could add (and index) a field on your models which could provide this functionality for you, which you can populate in an after_create callback.
<shameless_plug>
Alternatively, if you're just looking for a shorter solution to the default Mongoid IDs, I could suggest something like mongoid_token which makes it pretty easy to add shorter tokens/ids to your Mongoid documents.
</shameless_plug>