I am completely new to neo4j and I am very sorry for asking such a basic question. I have installed neo4j, I am using the shell "localhost:7474/webadmin/#/console/"
I am looking for a good example that uses some shell commands to read from a pre-existing graph database, traverse, modify,... it and then perform some queries in order to learn it. I don't want to use any Java or Python, all I want is some command line examples that will allow me to learn neo4j.
I searched a lot but could not find a good sample code except one matrix example.
I appreciate any help.
One of the virtues of Neo4J is the excellent documentation and learning material it provides (especially compared to other Graph enabled DBs).
As mentioned, starting with The Cypher Tutorial is a good starting point.
Then, as you learn the basics, check out The Neo4J Manual which has detailed documentation on each and every Cypher language command (as well as many other interesting stuff).
Finally, when you start doing your own queries, keep close a copy of the Cypher Cheat Sheet which summarizes all the commands.
You can even take a look at Cypher without installing or running Neo4J server, just going to the Neo4J Console and test your queries online (and even create links to them).
Caveat: when you start reading you may encounter with Gremlin, which is a common graph query language supported by Neo4J. Is quite awkward and very different from Cypher, so if you are going with Neo4J, you should stick to Cypher, it has more features and most of the development is made against it.
Cypher is your friend (there are several samples on this page):
http://www.neo4j.org/learn/cypher
Check out the Cypher-specific webinars:
http://watch.neo4j.org/
And finally, the Cypher cheatsheet:
http://neo4j.org/resources/cypher
Related
I would like to start a new project making use of fastapi. i would prefer mongodb as the storage backend and I would also like to have the whole thing 'speak' graphql.
In early 2022; what are the options? I see there's graphene-mongo... but I can't seem to find anything else.
I am trying to develop something with this tech stack but without success so far.
I am a front-end developer and am diving into the full stack universe. After trying many languages, frameworks and databases, this technology stack I found the most interesting for what I intend to do because of its flexibility.
But for now, I could not advance much and also found the same difficulty as you, very few examples available on the web.
My small example application uses FastAPI, is already connected to the MongoDB Atlas database and I tried using the Graphene library to expose a graphql endpoint of the database query result, but so far I haven't achieved any meaningful result.
I have also tried using the Strawberry library, which is suggested by the FastAPI documentation, but haven't achieved much yet either.
I will keep pushing to make this tech stack work and if I succeed, I can share my experience with you if you are still interested.
I'm fixing the usability/documentation for the mean stack. I'm starting with Mean.JS. Can someone give me the salient reasons why the authors of the MEAN stack use MongoDB as the database? There are other databases to choose, but MongoDB is used for some reason.
I realize there are questions already covering databases, but I'm wondering specifically why it was used in the MEAN stack scenario.
It think the primary reason is that MongoDB uses the same language Javascript (ECMA Script) for methods and functions API, rather than a separate language (like SQL). Thus MongoDB is a good no SQL database option, and it works much more efficiently as a database for the rest of the stack.
As others have pointed out, there are many other reasons, like that it is the most popular NoSQL database at this point. It has a decent shell and you can write Javascript in it. It is Open Source and well documented.
It is also really easy to setup, and scales fairly well, although not as good as some other NoSQL databases.
It also uses BSON, which is similar to JSON, which is similar to a Javascript object. So it is just plain easy to learn and easy to use this particular database with the rest of a Javascript stack.
There's some pretty good reasons here: http://blog.mongodb.org/post/49262866911/the-mean-stack-mongodb-expressjs-angularjs-and
A Glimpse Into Four Key Components - How MEAN Stack Adds New Dimensions To New-Age Web Applications
All four components of MEAN Stack are popular in the app development space. It offers a platform that enables an effortless development work process. Let’s know about every component and its unique features.
MongoDB – Independent database framework
For any web app building, data storage and management are essential. MongoDB is a popular database with NoSQL document to allow this purpose. The primary use case of this framework is to enable data storage and management of every web application development.(Read More)
I wanted to know if there is any Neo4j equivalent of a stored procedure?
When I researched this, I came across events, but I found them more like triggers and not stored procedures.
There are basically two techniques to extend a Neo4j server:
Server plugins enrich the existing REST endpoints and
unmanaged extensions allow to you create new REST endpoints
Both techniques require to write code in JVM (or other JVM language), package a jar file and deploy it to Neo4j server.
Stored procedures are available as capabilities CALLABLE from the Cypher language since version 3.0
A first reference can be found here
https://dzone.com/articles/neo4j-30-stored-procedures
A remarkable example, showing how graph can be processed in the large
through procedure to achieve network clustering and community
decetion, here
http://www.markhneedham.com/blog/2016/02/28/neo4j-a-procedure-for-the-slm-clustering-algorithm/
EDIT
As Neo4J 3.0 has been released in April'16, the stored procedure became an official, Apache 2.0 licensed, repository.
https://neo4j.com/labs/apoc/
Available procedures range from data manipulation/import to Spatial and complex graph algorithms (es. Page Rank, Dijkstra, Community detection, betweenness centrality , closeness centrality, etc)
My answer here does not answer the question directly (Stefan's answer does just fine for that). With that said, if any of you are considering writing server plugins (to get Stored Proc behavior) before your project is actually being used in production (which at the time of this writing is the vast majority of the Neo4j userbase), I strongly recommend not doing so.
Server plugins add architectural complexity to your project. You will require JVM developers to maintain them. Deploying or updating them can be tricky, and the associated source control methodologies are not intuitive. Neo4j doesn't require schema migrations, which makes your job as a developer easier. Adding server plugins will no longer give you that benefit, and since it's not a mainstream use case of Neo4j, you'll be getting little help from the developer community, and improvements and bug fixes related around that function will be given lesser priority from the Neo4j team.
And all that would be for possibly a slight performance boost, or none at all.
"Stored Procedures" (or using server plugins as such) are an important feature to have in the context of performance tuning, but if your team is still two guys in a garage, don't even think about going down this path.
i've been developing a asp mvc website for almost a year now exclusively on mongodb. i've loved it for the most part. development productivity has been great using a C# mongodb driver and tools like mongovue.
however, i've started to reach a point where there are things i really wish i had a SQL server database for. simple tasks like updating a record in the DB and only mildly complex queries to generate some type of report are becoming a pain.
i read an article somewhere that in order for NOSSQL to succeed there needs to be a standard query language for it, and tools developed around it. i'm guessing this is far far away, so right now i'm stuck trying to deal with these things.
i think eventually i will have to have a dual solution with monogDB and sql server. i don't think i will ever get to the point where i am as productive updating and writing queries for mongoDB as i was with sql server.
how are you guys dealing with this when using NOSQL like mongodb? are you facing the same issues as me?
One solution you may consider is LINQPad. You can set up a template with a reference to 10Gen's drivers and write ad-hoc, C# MongoDB queries like you would in your code. My team and I use this method to address the very problem you mention.
Try it out (it's free) and see if it can help with the simple, day-to-day queries you come up with.
Edit I also support Chris's suggestion of familiarizing yourself with the native JSON query language. Nothing beats a quick console window for speed, if you know the syntax.
The official C# driver will probably get a LINQ provider some time in the future, so that'd give .NET devs a familiar syntax for querying and maybe help with initial productivity. There're also some nice docs that help relate MongoDB queries back to SQL:
SQL to Mongo Mapping Chart
SQL to MongoDB (PDF)
These are great for learning, but to get the most out of Mongo it's well worth investing time getting used to the native JSON query syntax and Mongo-specific concepts like map-reduce.
Since your questions asks,
how are you guys dealing with this when using NOSQL like mongodb?
I thought I'd chime in. I felt your pain when working with another NOSQL database, RavenDB.
I wrote a Linqpad driver specifically for ad hoc interactions with RavenDB.
https://github.com/ronnieoverby/RavenDB-Linqpad-Driver
I am looking into something lightweight, that, at a minimum should support the following features:
Support for easy definition of actions through metadata
Wrapper that extracts parameters from request into clojure map, or as function parameters
Support for multiple forms of authentication (basic, form, cookie)
basic authorization based of api method metadata
session object wrapped in clojure map
live coding from REPL (no need to restart server)
automatic serialization of return value to json and xml
have nice (pluggable) url parameter handling (eg /action/par1/par2 instead of /action?par1=val1&par2=val2)
I know it is relatively easy to roll my own micro-framework for each one of these options, but why reinvent the wheel if something like that already exists? Especially if it is:
Active project with rising number of contributors/users
Have at least basic documentation and tutorial online.
First of all, I think that you are unlikely to find a single shrinkwrapped solution to do all this in Clojure (except in the form of a Java library to be used through interop). What is becoming Clojure's standard Web stack comprises a number of libraries which people mix and match in all sorts of ways (since they happily tend to be perfectly compatible).1
Here's a list of some building blocks which you might find useful:
Ring -- Clojure's basic HTTP request handling library; all the other webby libraries (for writing routes &c.) that I know of are compatible with Ring. Ring is being actively developed, has a robust community, is very well-written and has a nice SPEC document detailing its design philosophy. This blog post provides a nice example of how it might be used (reacting to GitHub commits).
Sandbar -- currently an authentication library, more types of functionality planned; under development.
Compojure -- a mature and robust library which provides a nice DSL for writing routes to be used on top of Ring. This will give you the nice URL parameter handling.
Compojure-rest -- "a library for building RESTful applications on top of Compojure". Compojure-rest is, as far as I can tell, in its early stages of development; perhaps you might see this as an opportunity to influence its design. :-)
For dealing with XML, there's clojure.contrib.lazy-xml (and the helper library clojure.contrib.zip-filter.xml) and Enlive (the built-in clojure.xml namespace is currently not very usable); these would be used in tandem (though for your purposes the former might suffice).
For JSON, there a library in contrib and clojure-json (and I think there was at least one other lib I seem to be forgetting now...); pick the one you like best.
All of will be perfectly happy with a REPL-driven development style (see the accepted answer to this SO question for a Ring trick which is very much to the purpose here). I suppose the above collection of links does leave a few blind spots (in particular, the authentication story is still being ironed out, as far as I can tell), but hopefully it's a good start.
1The only single-package solution for building webapps in Clojure that I know of is Conjure, inspired by Rails; unfortunately I have to admit that I don't know much about it, so if you feel interested, follow the link and look around the sources, wiki &c.
While building my first Clojure rest service I found myself asking often the same question. The Clojure Toolbox helped me a lot: http://www.clojure-toolbox.com/
If you are looking for some sample, real-world, illustrative code to get you started, then you could study this clojure-news-feed on github project which demonstrates how to implement a non-trivial RESTful web service with compojure/ring that wraps both SQL (postgresql or mysql) and NoSQL (cassandra), search (solr), caching (redis), event logging (kafka), connection pooling (c3po), and real-time metrics via JMX.
This blog about Building a Scalable News Feed Web Service in Clojure provides a good introduction. I ran some load tests against this service on a humble AWS deployment and got about eighty transactions per second with less than a half second average latency per transaction.
Take a look at liberator library http://clojure-liberator.github.io/liberator/ It's noy a standalone solution, buy very good for rest service definition.
Just to provide an updated answer to this old question, currently (in 2018) I think Luminus provides an excellent starting point. It's using many of the libraries (ring, compojure, etc.) mentioned in previous answers, is modular and as close to "single package" as you can get with Clojure. Specifically for REST, take a look at compojure-api. Luminus recommends buddy for authentication, I've had good success using it both for traditional session-based auth as well as Oauth and stateless JWTs.