New to neo4J and love the browser for exploratory work. But, I'm unsure of how to best use it to achieve, for lack of a better term, real work. Consider a sample project involving:
Importing 4 different CSV files
Creating appropriate relationships between nodes
Doing a variety of complex queries to derive data that I'll export for statistical analysis using another program.
I need to be able to replicate the project in the future, as well as adding new data, calculating different derived data, etc. I also need to be able to share the code so others can extend/verify it.
For non-relational data, I'd use something like R, Stata or SAS. While each allow interactive exploration like the neo4J browser, I'd never use that for serious analysis. Instead, I'd save a file or files of commands that I could modify and rerun whenever I needed to.
Neo4j's browser doesn't seem to support any of this functionality. Unless I am missing something, it doesn't even allow one to save a "session" along the lines of a iPython/Jupyter notebook. I know that there is a neo4-shell, but especially since they have dropped it from the standard desktop installation (and gotten rid of the console), I feel like I must be doing something wrong--or at least contrary to the designers' intent--if I can't do serious work in the browser. Clearly, lots of people are.
Can anyone point me in the right direction? How does one best develop an extensive, replicable project over time with neo4j? Thank you.
You can take your pick of several officially-supported language drivers to integrate neo4j into basically any other project structure, including Jupyter notebooks. I'm not sure what exactly you mean by "serious work", or where you got the idea that people did lots of it in the browser, but you are definitely able to save the results of a query from the browser in a variety of formats (pictures of the bubbles, result rows in a CSV, JSON response) if your prefer to work that way, or you can pipe data very efficiently into another language and manage it there. I don't see why they would re-create presentation and/or project management tools when there are already so many good ones out there.
Related
Using rails and postgresql.
I wrote my app without having in mind to use a master slave configuration.
Now, I've gotten master slave set up in the app and now I'm running into some technical debt. The same process in my app writes to the db and then immediately reads from the db. The read is not taking place on the read db but the data isn't there. Before, this wasn't efficient but it didn't cause any problems because both dbs were the same. Now, this is blowing up in my face.
The problem for me is that its difficult to find all the places in the code where this problem exists. Can someone can please suggest to me a technique to get my tests to run in such a way where the reads and the writes use different dbs that aren't updated so that I can figure out where my issues are?
Other solutions will also be welcomed!
I strongly recommend you rethink your master/slave configuration or whether master/slave is even right for your application.
It's not "tech debt" to build a system that assumes data written to persistent store can be read back immediately. It's normal and correct. While you might reasonably be able to avoid the pattern
write A, ..., look up A.key
with various simple cache schemes, trying to code around e.g.
write A, ..., complex query that *might* fetch A
requires you to retain a copy of A and determine whether it would satisfy the WHERE clause of the query in separate code, simply because you can't rely on the query results. Unless your system is very small and simple, trying to do this system-wide will produce a super-complex, fragile, expensive, and ugly code base. I strongly recommend you don't try it.
The usual purpose of a master/slave persistent store organization is to off-line read traffic that's not time-dependent on writes. For example, if your system mines data to produce summaries accessible to users, you'd offline the metric computation and have it mine the slave. This prevents mining queries from drawing resources away from user request handling. The small delay between write on master and copy to slave is no problem.
If your app is struggling because there's too much load on persistent store, you probably want partitioned data (sometimes called sharding), not master/slave. Partitioning can expose you to a different kind of problem: no cross-partition transactions. But this is usually easier to work through than what you're attempting.
After studying this area, I agree with Gene that master slave should only be used for reads that have been written a significant time before the read.
My ORIGINAL concept was that its better to utilize a functional programming style whereby the process retains all the information in the parameters and then doesn't make recourse to the database. The downside of this approach is that the human mind has a hard time with functional programming and in a massive computer program it makes sense to not insist on this added complication.
If you want to write a functional method or process then that is great and very efficient but there shouldn't be anything in the code that insists on this.
I am looking for information on tools, methods, techniques for analysis of file path names. I am not talking file size, read/write times, or file types, but analysis of the path or URL it self.
I am only aware of basic word frequency text tools or methods, but I am wondering if there is something more advanced that people use/apply to this to try and mine extra information out of them.
Thanks!
UPDATE:
Here is the most narrow example of what I would want. OK, so I have some full path names as strings like this:
F:\Task_Order_Projects\TO_01_NYS\Models\MapShedMaps\Random_File1.doc
F:\Task_Order_Projects\TO_01_NYS\Models\MapShedMaps\Random_File2.doc
F:\Task_Order_Projects\TO_01_NYS\Models\MapShedMaps\Random_File3.doc
F:\Task_Order_Projects\TO_01_NYS\Models\MapShedMaps\Random_File4.doc
F:\Task_Order_Projects\TO_01_NYS\Models\MapShedMaps\Random_File5.doc
F:\Task_Order_Projects\TO_02_NYS\Models\MapShedMaps\Random_File1.doc
F:\Task_Order_Projects\TO_02_NYS\Models\MapShedMaps\Random_File2.doc
F:\Task_Order_Projects\TO_02_NYS\Models\MapShedMaps\Random_File3.doc
F:\Task_Order_Projects\TO_02_NYS\Models\MapShedMaps\Random_File4.doc
F:\Task_Order_Projects\TO_02_NYS\Models\MapShedMaps\Random_File5.doc
What I want to know is that the folder MapShedMaps appears "uniquely" 2 times. If I do frequency on the strings I would get 10 appearances. The issues is that I don’t know what level in the directory this is important, so I would like a unique count at each level of the directory based on what I am describing.
This is an extremely broad question so it is difficult for me to give you a per say "Answer" but I will give you my first thoughts on this.
First,
the Regular expression class of .NET is extremely useful for parsing large amounts of information. It is so powerful that it will easily confuse the impatient, however once mastered it can be used across text editors, .NET and pretty much any other respectable language I believe. This would allow you to search strings and separate it into directories. This could be overkill depending on how you use it, but its a thought. Here is a favorite link of mine to try out some regular expressions.
Second,
You will need a database, I prefer to use SQL. Look into how to connect to databases and create databases. With this database you can store all the fields abstracted from your original path entered. Such as a parent directory, child directory, common file types accessed. Just have a field for each one of these and through queries you can form a hypothesis as to redundancy.
Third,
I don't know if its easily accessible but you might look into whether windows stores accessed file history. It seems to have some inkling as to which files have been opened in the past. So there may be a resource in windows which already stores much of the information you would be storing in your database. If you could find a way to access this information. Parse it with regular expressions and resubmit it to the database of your application. You could control the WORLD! j/k... You could get a pretty good prediction as to user access patterns though.
Fourth,
I always try to stick with what I have available. If .NET is sitting in front of you, hammer away at what your trying to do. If you reach a wall. At least your making forward progress. In today's motion towards object orientated programming, you can usually change data collected by one program into an acceptable format for another. You just gotta dig a little.
Oh and btw, Coursera.com is actually doing a free class on machine learning and algorithms. You might want to check it out or reference it for prediction formulas.
Good Luck.
I wanted to post this as a comment but SO kept editing the double \ to \ and it is important there are two because \ is a key character, without another \ to escape it, regex will interpret it as a command.
Hey I just wanted to let you know I've been playing with some regex... I know a pretty easy way to code this up in VB.net and I'll post that as my second answer but I wanted you to check out back-references. If the part between parenthesis matches it captures that text and moves on to the second query for instance....
F:\\(directory1)?(directory2)?(directory3)?
You could use these matches to find out how many directories each parent directory has under it. Are you following me? Here is a reference.
I'm looking to go through a bunch of text files in a bunch of folders. I'd like to go through each file line by line and do some basic statistics, like grabbing time stamp and count repeating values. Is there any tool or scripting solution that someone could recommend for doing this?
Another possibility is to have a script/tool that could just parse these files and add them to a database like sqlite or access, for easy filtering.
So far I tried using AIR, but it looks like there might be too much data for it to process, and it hangs, but that could be because of some inefficient filtering.
I have used QuickMacros for things like this. It can do just about anyting to a textfile (some illegal in 7 states) as well as connect to databases and perform sql tasks like create and modify tables etc.
I routinely used it to extract data, parse it, and then load it into another database. Especially useful with Scheduled Tasks.
Here's the website
I recommend Perl and CPAN
I am building out some reporting stuff for our website (a decent sized site that gets several million pageviews a day), and am wondering if there are any good free/open source data warehousing systems out there.
Specifically, I am looking for only something to store the data--I plan to build a custom front end/UI to it so that it shows the information we care about. However, I don't want to have to build a customized database for this, and while I'm pretty sure an SQL database would not work here, I'm not sure what to use exactly. Any pointers to helpful articles would also be appreciated.
Edit: I should mention--one DB I have looked at briefly was MongoDB. It seems like it might work, but their "Use Cases" specifically mention data warehousing as "Less Well Suited": http://www.mongodb.org/display/DOCS/Use+Cases . Also, it doesn't seem to be specifically targeted towards data warehousing.
http://www.hypertable.org/ might be what you are looking for is (and I'm going by your descriptions above here) something to store large amounts of logged data with normalization. i.e. a visitor log.
Hypertable is based on google's bigTable project.
see http://code.google.com/p/hypertable/wiki/PerformanceTestAOLQueryLog for benchmarks
you lose the relational capabilities of SQL based dbs but you gain a lot in performance. you could easily use hypertable to store millions of rows per hour (hard drive space withstanding).
hope that helps
I may not understand the problem correctly -- however, if you find some time to (re)visit Kimball’s “The Data Warehouse Toolkit”, you will find that all it takes for a basic DW is a plain-vanilla SQL database, in other words you could build a decent DW with MySQL using MyISAM for the storage engine. The question is only in desired granularity of information – what you want to keep and for how long. If your reports are mostly periodic, and you implement a report storage or cache, than you don’t need to store pre-calculated aggregations (no need for cubes). In other words, Kimball star with cached reporting can provide decent performance in many cases.
You could also look at the community edition of “Pentaho BI Suite” (open source) to get a quick start with ETL, analytics and reporting -- and experiment a bit to evaluate the performance before diving into custom development.
Although this may not be what you were expecting, it may be worth considering.
Pentaho Mondrian
Open source
Uses standard relational database
MDX (think pivot table)
ETL ( via Kettle )
I use this.
In addition to Mike's answer of hypertable, you may want to take a look at Apache's Hadoop project:
http://hadoop.apache.org/
They provide a number of tools which may be useful for your application, including HBase, another implementation of the BigTable concept. I'd imagine for reporting, you might find their mapreduce implementation useful as well.
It all depends on the data and how you plan to access it. MonetDB is a column-oriented database engine from the most revolutionary team on database technologies. They just got VLDB's 10-year best paper award. The DB is open source and there are plenty of reviews online praising them.
Perhaps you should have a look at TPC and see which of their test problem datasets match best your case and work from there.
Also consider the need for concurrency, it adds a big overhead for any kind of approach and sometimes is not really required. For example, you can pre-digest some summary or index data and only have that protected for high concurrency. Profiling your data queries is the following step.
About SQL, I don't like it either but I don't think it's smart ruling out an engine just because of the front-end language.
I see a similar problem and thinking of using plain MyISAM with http://www.jitterbit.com/ as data access layer. Jitterbit (or another free tool alike) seems very nice for this sort of transformations.
Hope this helps a bit.
A lot of people just use Mysql or Postgres :)
After much reading on ruby on rails and multiple database connections, it seems that I have found something that not that many folks do, at least not with ror. I am used to querying many different databases and schemas and pulling back the information either for a report or for one seamless page. So, a user doesn't have to log on to several different systems. I can create a page that has all the systems on one or two web pages.
Is that not a normal occurrence in the web and database driven design?
EDIT: Is this because most all my original code is in classic asp?
I really honestly think that most ORM designers don't seem to take the thought that users may want to access more than one database into account. This seems to be a pretty common limitation in the ORM universe.
Our client website runs across 3 databases, so I do this to. Actually, I'm condensing everything into views off of one central database which then connects to the others.
I never considered this to be "normal" behavior though. I would guess that most of the time you would be designing for one system and working against that.
EDIT: Just to elaborate, we use Linq to SQL for our data layer and we define the objects against the database views. This way we keep reports and application code working off the same data model. There is some extra work setting up the Linq entities, because you have to manually define primary keys and set up associations... however so far it has definitely proven worthwhile. We tried to do so with Entity Framework, but had a lot of trouble getting the relationships set up appropriately and had to give up. The funny thing is I had thought Entity Framework was supposed to be designed for more advanced scenarios like ours...
It is not uncommon to hit multiple databases during a single part of an application's workflow. However, in every instance that I have done it, this has been performed through several web service calls, which among other things wrap the databases in question.
I have not, to my knowledge, ever had a need to hit multiple databases directly at once and merge results into a single report.
I've seen this kind of architecture in corporate Portals- where lots of data is pulled in via different data sources. The whole point of a portal is to bring silo'd systems together- users might not want to be using lots of systems in isolation (especially if they have to sign into each one). In that sort of scenario it is normal, particularly if it is a large company that has expanded rapidly and has a large number of heterogenous systems.
In your case whether this is the right thing to do depends on why you have these seperate DBs.
With ORM's it may be a little difficult. However, it can be done. Pull the objects as needed from the various databases, then use them as a composite to create a new object that is the actual one that is desired. If you can skip the ORM part of the process, then you can directly query the databases and build your object directly.
Pulling data from two databases and compiling a report is not uncommon, but because cross-database queries cannot be optimized by the query engine of either database, OLTP systems typically use a single database, to keep the application performant.
If you build the system from the ground up, it is not advisable to do it this way. If you are working with a system you didn't design, there is no much choice and it is not uncommon (that is the difference between "organic" and "planned" grow).
Not counting master and various test instances, I hit nine databases on a regular basis. Yes, I inherited it, and yes, "Classic" ASP figures prominently. Of course, all the "brillant" designers of this mess are long gone. We're replacing it with things more sane as quickly as we safely can.
I would think that if you're building a new system, and keep adding databases and get to the point of two or three databases, it's probably time to re-think your design. OTOH, if you're aggregating data from multiple, disparate systems, then, no, it's not that strange. Depending on the timliness you need, and your budget for throwing hardware at the problem, and if your data is mostly static, this would be a good scenario for a "reporting server" that pulls the data down from the Live server periodically.