Currently, my schema for my mongodb app is very straightforward. However, I'd like to simplify and clean it up further. What's the best way of updating my schema design? Should I just write a remapper in my language of choice using a library (fairly trivial), or is there a simpler way?
I don't mind doing the above, I just would like to know if there's a really obvious way of doing it reliably.
You dont have to migrate your schema, mongodb like any NoSQl system is an answer to schema problems of RDBMS.
That said, you will have to migrate your data by making a migration script.
You might find this answer useful.
Related
The answer I got from an IRC channel:
Sequelize is an ORM that includes some query builder stuff; Knex is just a query builder, not an ORM.
ORMs don't actually fit very well in many use cases, it's easy to run up against the limits of what they can express, and end up needing to break your way out of them.
But that doesn't really explain the pros and cons of each. I am looking for an explanation, and possibly a simple example (use case) highlighting those similarities / differences.
Why would one use one over the other?
Sequelize is full blown ORM forcing you to hide SQL behind object representation. Knex is plain query builder, which is way too low level tool for application development.
Better to use objection.js it combines good parts of ORMs without compromising power of writing any kind of SQL queries.
Here is good article about it from the author of objection.js https://www.jakso.me/blog/objection-to-orm-hatred
Disclaimer: I'm knex maintainer and been also involved in development of objection.js.
Think of it like this which is the better performance and which is easier to learn.
As low level Database driver
For postgresql you can use pg as a query builder
As intermediate level you can use knex
As high level you can use ORM like sequelize, bookshelf, objection which is based on knex
Now low level doesn’t mean a bad thing. It’s the best performance you can get but the down side is you need to learn queries of the database you are using
Now knex is the same as a query builder the same cost operation
Now the highest level have the highest cost
But it’s easy to learn but the down size if you learn sequelize and decided to use objection they are different so you will need to learn another ORM
My suggestion if you want the best performance for a scalable complex backend server you can use query builder or knex
If you want to feel like dealing with objects instances like mongoose you can use Sequelize.
The only difference is the cost operating and it’s not large.
But ORMs have more functionality.
Of course you can refer to this article to understand more
About ORM
https://blog.logrocket.com/why-you-should-avoid-orms-with-examples-in-node-js-e0baab73fa5/
I am new to NoSql databases. I am trying to build a project and stuck with the approach of whether to choose sql databases or NoSql Databases for the project.
The requirements of my project are a legal firm would have many clients and each client can have different matter Type such as Immigration, Conveyancing, Family and etc and each MatterType can also have different fields which are never constant and they can fairly change in future.
Due to this nature I thought Nosql databases might be a good choice as they are document based and I can add any new fields to the document structure instead of always adding new columns to a sql data table dynamically which is not a good approach ( atleast i think)
Can anyone please kindly suggest me or refer me to an article which can assist me in deciding my approach
To give my clarity into my question let me explain with an example
For a client name xyz and matterType Immigration I can have fields such as firstName,lastName,Dob at this moment but later on for the same client I might have to add Dependants and their details
For a client name def and matterType conveyancing I would have different fields but those fields should also be added dynamically depending on the matter Type
Thank you in advance
Regards
Anand
In my opinion, you shouldn't only consider this feature in other to decide between NoSql or RBMDS.
In fact, this flexibility sounds very good, but it might be dangerous, once systems tend to raise, then things can get out of hand.
I have a system where I use MongoDB, but even though, I decided creating a schema for my collections.
I would suggest you finish modeling, then after that, conclude if it's really necessary to use NoSql.
I would like to suggest you to look into postgres sql if you are expecting large datasets. It offers the advantages of no sql databases such as support for key value pair and also keeping a rigid data structure like sql databases. Following are links to a few articles which may help you decide which approach to choose:
NoSql vs Sql
postgres vs mongodb
Hullo,
I have a crux to bear with Mongoose.
Is there a way of using JSON-Shema with Mongoose Schemas?
Say I want to define my API data schema using a standard like JSON-Schema, because it's nice.
It seems like I need to define it again when I want to use Mongoose / MongoDB!
That's quite some ugly duplication I like to avoid. Ideally, changing the JSON-Schema definition would also change the MongoDB schema.
A similar problem would appear if I would use JOI.JS validation library.
Has anyone found a solution to that?
Or is there an alternative approach?
thanks
Try this library: https://www.npmjs.com/package/json-schema-to-mongoose There are others out there too. I created json-schema-to-mongoose since the other libraries didn't quite fit my needs.
Also, I like to generate the json-schema from TypeScript using Typson. It makes it so the json-schema is more statically typed.
Update
It appears the Typson project is dead. Here's another (typescript-json-schema) project which does the same thing, although I've never used it.
Chiming in here since I've also run into this problem and found a solution that is alternative to the suggestions provided.
One can use https://github.com/nijikokun/generate-schema to take a plain JS object and convert it to both JSON Schema and a Mongoose Schema. I find this tool to be easier in the case of retrofitting existing code with validation and persistence since you will likely already have an example object to start with.
I'm working on a "real-time" website using Nodejs. Currently, I'm using Redis because I need high performance for read-access. The write accesses are not really significant for my use case.
In addition, Redis does not have a query language for the search. So, I create my indexes manually and I use some unions/intersections/... to find some values.
I think that it will be easier to use MongoDB with a embedded finding system and a ORM-like (Mongoose for example). The problem is that I'm not sure that MongoDB is the best choice for my usecase.
What is your advices about the NoSQL DB that I need ? Redis ? CouchDB ? MongoDB ? Cassandra ? etc.
I repeat: I want to have a real good performance for the read accesses and for the searches (the write accesses are not significant), the simplest possible (orm-like ? finding system ? etc.)
Thanks.
I believe that redis would be the better solution for the following reasons.
You require fast read access and redis provides the fastest solution since the keys are in memory, if not most.
Although mongodb is easier to query in the general case, your problem domain is narrow and once you decide how you would like to query the data, you can put the correct data structures and indexes in place.
I would say that Redis is a good fit for your DB, and you should look at something like Solr or elasticsearch to provide your searching.
CouchDB will do better in write heavy environment. I don't use it though.
MongoDB will do better on read heavy environment.
For search and indexing:
MongoDB would require separate index for each of your search criteria for better performance (at least this is what I remember).
Proper index is important in MongoDB. And no joins!!
Here are some links you might go through:
http://www.mongodb.org/display/DOCS/Comparing+Mongo+DB+and+Couch+DB
http://www.snailinaturtleneck.com/blog/2009/06/29/couchdb-vs-mongodb-benchmark/
http://kkovacs.eu/cassandra-vs-mongodb-vs-couchdb-vs-redis
Hope these will help you find the right db
Goodluck
I've been learning Node.js so I decided to make a simple ad network, but I can't seem to decide on a database to use. I've been messing around with Redis but I can't seem to find a way to query the database by specific criteria, instead I can only get the value of a key or a list or set inside a key.
Am I missing something, or should I be using a more robust database like MongoDB?
I would recommend to read this tutorial about Redis in order to understand its concepts and data types. I also had problems to understand why there is no querying support similar to other (no) SQL databases until I read few articles and try to test and compare Redis with other solutions. Maybe it isn't the right database for your use case, although it is very fast and supports advanced data structures, but lacks querying which is crucial for you. If you are looking for a database which allows you to query your data then you should try mongodb or maybe riak.
Redis is often referred to as a data
structure server since keys can
contain strings, hashes, lists, sets
and sorted sets.
If able(easy to implement) you should use these primitives(strings,hashes,lists,set and sorted sets). The main advantage of Redis is that is lightning fast, but that it is rather primitive key-value store(redis is a little bit more advanced). This also means that it can not be queried like for example SQL.
It would probably be easier to use a more advanced store, like for example Mongodb, which is a document-oriented database. The trade-off you make in this case is PERFORMANCE, but I believe you should only tackle that if that is becoming a problem, which it probably will not be because Mongodb is also pretty fast and has the advantage that it can be queried. I think it would be advisable to have proper indexes for your queries(read>write) to make it fast.
I think that the main answer comes from the data structure. Check this article about NoSQL Data Modelling, for me it was very helpful: NoSql Data Modelling.
A second good article ever about Data Modeling, and making a comparison between SQL and NoSQL is the following: The Relational model anti pattern.