Actually, how many kind of database are there? - sql

I am new at database administrator, i just want to mapping actually, how many kind of database are there. I made this map, i want to ask, Is it true ?
Simply, I wanna to make map likes Historical Tree / Genealogy of database.
https://drive.google.com/file/d/0B4VwAhmXH2OVbm8yTm9ld1oxY1E/view?usp=sharing

cassandra and hbase are column store databases. I think these are missing in NoSql databases and ArangoDB is a multi-model database which supports Key-value, document storage and graph

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how to find a way for mongodb schema?

I'm new to MongoDB. before I start MongoDB i was working with SQL databases. I know that MongoDB is different from SQL and in Mongodb you don't have to define a schema. but if you give your database to other teammates and ask him to work with your database, how he can figure out how to work with a Collection? in this situation in SQL, your teammate will open the database and look at the Table and he will understand how to work with it. Suppose according to your analyze, the User Collection should hold the following data model:
But when you have not defined it anywhere, How can you explain it to others?
I hope that I have been able to express my meaning correctly.

How do I set up the relationship between tables using firebase?

I want to create a relational table on the google console screen using firebase. How can I make the relationship between the user table and the user's posts table on the google console screen
Both databases offered by Firebase, Realtime Database and Cloud Firestore, are both NoSQL type databases. By definition, this means that they are non-relational. They do not have tables, and there are no joins. You can't set up relationships between collections or nodes.
With Cloud Firestore, you can use a DocumentReference type field to have one document point to another document, but that doesn't help you with constructing a query that joins those two documents together.
If you want to use either of the databases that Firebase offers, please take some time to get acquainted with NoSQL data modeling techniques. There are plenty of tutorials out there, as well as the product documentation for each product.
NoSQL databases haven't data relationship with tables. Also they also saves documents in a json format.
nosql ecommerce data model maybe help for you

Is maprdb a document store or a key value store

I know that mapr db exposes OJAI interface to query using json documents and hbase api's using which we can create column families.
I want to know how does mapr db store data on file system, and what kind of queries are costly and what kind of queries are cheap (for which maprdb is really made for).
It would be really helpful if some one can give some guidelines on what basis should we create column families if we are using hbase api's to access maprdb.
Please share any references that can answer this question

wso2cep : Data Storage in addition to display

I was wondering if in addition to process and display data on dashboard in wso2cep, can I store it somewhere for a long period of time to get further information later? I have studied there are two types of tables used in wso2cep, in-memory and rdbms tables.
Which one should I choose?
There is one more option that is to switch to wso2das. Is it a good approach?
Is default database is fine for that purpose or I should move towards other supported databases like sql, orcale etc?
In-memory or RDBMS?
In-memory tables will internally use java collections structures, so it'll get destroyed once the JVM is terminated (after server restart, data won't be available). On the other hand, RDBMS tables will persist data permanently. For your scenario, I think you should proceed with RDBMS tables.
CEP or DAS?
CEP will only provide real-time analytics, where DAS provides batch analytics (with Spark SQL) in addition to real-time analytics. If you have a scenario which require batch processing, incremental processing, etc ... You can go ahead with DAS. Note that, migration form CEP to DAS is quite simple (since the artifacts are identical).
Default (H2) DB or other DB?
By default WSO2 products use embedded H2 DB as data source. However, it's recommended to use MySQL or Oracle in production environments.

Use SQL or NoSQL?

I'm designing a system that checks a given website for any security vulnerabilities. The system includes a client (firefox plugin) and a server. The server does all the scanning while the client just relays that info to the user. If a website is dangerous, it is blacklisted; otherwise whitelisted.
The system must hypothetically be able to handle several thousands of requests and updates to the database simultaneously.
Although the database is expected to have a very simple structure, I am still considering using NoSQL because my understanding is that it can handle a greater amount of queries. Is this true? Which db technology is better suited for my system?
I suggest a NoSQL database.
In fact I've been working with two databases in the last weeks, and searching on internet I found the differences between a NoSQL an a SQL database.
Pratically, you should use a NoSQL db if you have a lot of data to query. Remind that it's not sure the data recovery in case of a db disaster.
Instead, use a SQL database if your data MUST be permanent, and you can't lose it. But query times will be longer, so it's not suggested if you have tons of data.
I understood, from what you wrote, that you need lot of queries and you "can lose" the data (if you lose a website of the list, you'll just need to re-check it, right?).
So I suggest you to go for a NoSQL db (I worked with MongoDb, it is the most famous worl-wide).
If you consider NoSQL Databases you have to analyze your data to get the right Database.
For your use case I think you should look at document databases (like MongoDB) or, if you want really high performance, a key-value Database like Redis or Riak.
With Key-Value databases you can only use the key to find the data you want.
With document databases you still have some kind of querys to find the data.
For further information look at: http://nosql-database.org/