I recently started to learn Clojure and my intention is to build a simple CMS using it for practice. Since Clojure is a purely functional language and it requires a new way of thinking it just came up for me that what if I use a NO-SQL database for my application like MongoDB?
Do you have any comparison in this topic? I searched on google but I failed to dig up any usable data regarding this matter. What are the pros and the cons?
edit: I mentioned clojure and web development to put things in context. For example with clojure it is easier to write a domain-specific language than for example using java.
Whatever the language, you will gain a lot from using a no-sql database if you observe some OOP principles that Domain Driven Design brings to the table. The idea of an Aggregate and the Aggregate Root allow you to form organization in a more document-centric way. Since no-sql data manipulation is tailored to key-value pairs, aggregates and aggregate roots are something to investigate.
Also if you feel like learning more on how to organize your architecture to involve both sql and no-sql, take a look at the CQRS "pattern". You can tailor the write side to use no-sql but keep traditional SQL or RDBMS on the read side.
CQRS: http://martinfowler.com/bliki/CQRS.html
DDD: http://domaindrivendesign.org/
Let me know if you have any questions.
I don't think this is really a Clojure question, or am I misinterpreting it? Are you looking for the pros and cons of using a NOSQL vs. SQL database for your web application?
Either way both approaches are easy to use in Clojure, there are libraries out there.
Check out: -
congomongo
Related
I am considering rewriting a large project using Spray. I am unsure what is currently the best choice for accessing an RDBMS. I need to support Oracle and PosgreSQL and, as I am restricted to a free solution, Slick is rather not an option here.
I often use MyBatis in my Java projects, so I consider MyBatis-Scala as a possible solution, but this is just a wrapper for a Java library.
Which native Scala library fits best into Spray?
In my oppinion it is not the matter of "fitting" into Spray, but the matter of good strategic choice.
Please consider options of scala database frameworks. My personal preference is squeryl and sorm. Both of them provide pretty much nice DSL and are written in scala.
Also you can have a look at one more review of available scala frameworks (a bit outdated but well structured to give a basic idea).
Hope it helps.
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'm developing a brand new project in Scala. It's just an application for a bunch of CRUD operations, however, because of some eccentric requirements, Play2 or Lift does not fit the bill, so I'm going to develop the application from the ground up. This means that Anorm or ScalaQuery becomes less obvious choices for database integration, and leaves me with the question: is it time to try something new?
My past technology stacks mostly included Java and PostgreSQL and I have experience with both ORM and plain SQL. Are NoSQL database management systems like MongoDB a good replacement for a typical RDBMS or are they special case application data stores? Also, how does the choice of database effect the greater Scala system design (if at all)? For example, the fact that you are using a JSON-like interface to talk to the database, and JSON between the web and a REST service, does not mean that much if everything in the middle becomes Scala objects, or does it?
I'm basically asking for someone's experience on moving from relational to object/document type databases, using Scala in particular. I know that good RDBMS integration is promised in the upcoming release of SLICK. So, if a company like TypeSafe decides to make a RDBMS integration part of the TypeSafe stack, then will I be swimming upstream by integrating to MongoDB using Casbah for example?
Apologies if this question appears a bit vague. I do hope that someone with the right insights or experience will be able to help though.
Update:
Apologies for not adding links to SLICK (it being fairly new). Here goes:
Quick overview
Project home
Update 2:
My personal first win for a technology is usually developer productivity - this translates to lightweight and simple: quick to learn, easy to maintain, no magic
I am currently in a similar situation, and since I have some experience with web development and SQL databases, I took it as an opportunity to work with MongoDB, Cashbah (and Scalatra). My experience is still very limited and the project and the amount of data I am working with is pretty small, but here are a few observations I've made.
For the few sets of data I have, performance does not seem to motivate either SQL or NoSQL. However, performance in the presence of huge amounts of data is often listed as a reason for using NoSQL, e.g., by Wikipedia
My documents (entries in the database) arise from benchmarking test suits, and mainly have a static structure, and I am optimistic that I could store them in a fixed-schema SQL database. However, a few substructures are not static, e.g., new test cases are added, new statistics are tracked, others are removed. This was my main motivation for trying a schema-free NoSQL database. Also, because I had the feeling that the document approach of MongoDB makes it much more obvious which data belongs together (i.e., to a document), in contrast to entries in a relational database, where the data would be distributed over various tables and rows, and where a full "document" would need to be reconstructed by joins.
Tools such as Lift-Json or Rogue allow you to work with regular Scala objects in a type-safe, although the data is regularly (de-)serialised as (from) JSON. However, this naturally works best if the structure of your data is mainly static, otherwise, you you are left with using strings to access your data (e.g., for expanding the results of a query using Cashbah).
If you are mainly concerned about a coherent representation of data on server and client side, languages such as Opa or Haxe might be of interest, since they compile to code that can executed on both sides. See this page for "multitarget" or "tierless" languages.
Got too long for a comment. Was just trying to relate my short experience with Scala (about 6 months now, since about when Play2 came out--it's quickly become my go to language).
I've enjoyed using Salat/Casbah with MongoDB in my last few projects; most have been in Play2, but the latest was without a webapp framework. It definitely hasn't felt like swimming upstream.
I would say that there are particular use cases for which I wouldn't use mongo, but it works nicely as a general purpose object data store, especially if you expect to query by id or index and don't need transactions (and will need minimal ad-hoc aggregation type stuff).
Expect to require a separate set of servers dedicated to mongodb (or to use a service dedicated to mongodb), but I guess that's normal for most serious database apps.
I've also used Play2/Anorm, which was surprisingly enjoyable to use for some ad-hoc query dashboard-style report pages. I started trying to go the Squeryl route, but Anorm seemed easier to use for one-off aggregation queries. Haven't looked at SLICK, but it sounds interesting.
It's really hard to say without knowing what problems you would like the app to solve.
I've personally found my productivity increased using NoSQL DBs via REST/JSON. Though bear in mind most NoSQL DBs offer REST interfaces which preclude the need for much middleware, Scala or otherwise, unless you intend to write a webapp with a UI.
If this is a learning exercise, I recommend you try multiple things out, as each NoSQL DB has something different to offer to your toolkit, and have personally found CouchDB, Riak, Neo4j, and MongoDb all with various pluses and drawbacks and good for different purposes.
Hope this helps, good luck.
I was on my way for the Development of an Ecommerce app. Is it possible to write a lithium application that works on different connections basically MongoDb or CouchDb and MySQL? How can we do it and what are your tips on achieving it?
I'm not sure if I understand you right.
If you just want to use more connections at the same time to different databases, this is easily possible. You can just define more connections at once (take a look at the default connections.php bootstrap file and also at the documentation for the lithium\core\Environment class).
If you want to run your whole application on all the database mentioned above, read on...
It is not easy to answer this question in general, but here are some thoughts on this:
As you may know, Lithium provides you with a database abstraction layer which exposes general methods for the CRUD process. As nice this is during development (you don't have to learn new interfaces for every database), you soon come to a point where you need database specific features.
This may raise compatiblitiy problems between relational databases, but is nearly impossible for mixing relational and non-relational databases. Of course you can use them side-by-side, but providing abstractions is really hard. For example, how would you query on nested documents (like you do in MongoDB) in MySQL? You could write a wrapper that tries to emulate this, but you shouldnt try to.
That said, if you really have to do this, you may achieve it with writing wrapper code and leave out very specific database-dependend features.
I searched a bit for the differences between OODBMS and RDBMS. I pretty much know what they are. However, how I will decide which one is better for which applications. Can anyone kindly help me please?
What I meant for factory management is: there are production lines to manufacture bottled, frozen and other food stuff. The application manages from assigning staff onto the lines, to keep the production records in the system. Which dbms is better for such systems?
Thanks in advance.
Here is a nice article by Rick Grehan that describes cases where ODBMS are useful:
http://www.odbms.org/wp-content/uploads/2013/11/006.04-Grehan-When-to-Use-an-ODBMS-2005.pdf
Disclaimer: this is an "old curmudgeon" answer, from a guy who wrote plenty of perfectly functional accounting, manufacturing and other code before OOP came into the mainstream.
With that being said...
Factory management is classic relational database stuff, it's what it was invented to do. The code for classic relational apps tends to follow very predictable patterns, lots of loops over retrieved rows from tables, or straight pass-through stuff: passing data up to the UI or down to the database. If your DB is well-designed, the biz logic you code will be details in those loops or pass-throughs, but those two patterns will dominate.
An OODMS on the other hand, from the point of view of this "old curmudgeon", attempts to recast the perfectly and efficiently functional RDBMS into something that will work with classes/objects, for no discernible gain over a system that has proven itself for decades to work extremely well. Classes have little or nothing to do with the classic code patterns that sit on top of relational databases. In fact, they tend to complicate things and can easily get in the way. I'm not saying don't use OOP code to deal with the database, just that OOP was invented for a different kind of problem, a problem that database apps don't happen to have.
Decision to choose OODBMS or RDBMS does not depend upon particular application like factory management/automation.
It is depends on many criteria like
1) Programming Paradigm - If you [programmer] choose to visualize/implement in the OO programming language then the OODBMS is suitable to store the objects as directly into the database, but Most widely the type of DBMS Relational, because it is well established commercially and have a good mathematical background.
2) Application Specific - For an factory automation/management, responsiveness and fast access is important. The OODBMS are swifter than the RDBMS. If you considered for web-development then a light-weight tool like MySQL will fit a lot.
3) Trend - Now there is paradigm swift from Legacy/Structural to Object/Component Oriented programming. so therefore, in this trend the OODBMS is best suitable for the Enterprise Applications like factory management, etc.
It depends on the application layer using. If it is a simple approach more towards procedural way [which can have classes too] RDBMS is more suitable. Otherwise if you are more towards a strict object oriented system OODBMS can be used.
I usually draw the line of usefulness at the point in which they need to be integrated into enterprise systems. If your project does not necessarily need to integrate, ODBMS is usually easier or technically superior. If you can integrate via web services or "push/pull" into an enterprise system DB, then you can still use an ODBMS, but there might be political pressure against it. (newer ODBMS/RDBMS replication like dRS for db4o may be a good fit) But if you need tight integration with legacy or enterprise datastores, then you're usually forced to use the RDBMS for one reason or another.
That said, your individual production lines might benefit greatly from an ODBMS which are great at storing oft-changing complex object models and schemas while the orchestrator system could follow my previous line of thinking.
I've been using ODBMS for many years, and have been dreading the project which requires me to return to purely relational data management. Although recent improvements in ORM tooling have made relational much more pleasant to work with, the ORM+RDBMS solution still can't keep up with ODBMS systems in a few key areas (see the previously mentioned article on odbms.org).