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2015, Friday December 11

Audit Trail for Services

We have seen previously how the ORM part of the framework is able to provide an Audit Trail for change tracking.
It is a very convenient way of storing the change of state of the data.

On the other side, in any modern SOA solution, data is not at the center any more, but services.
Sometimes, the data is not stored within your server, but in a third-party Service-Oriented Architecture (SOA).
Being able to monitor the service execution of the whole system becomes sooner or later mandatory.

Our framework allows to create an Audit Trail of any incoming or outgoing service operation, in a secure, efficient and automated way.

Continue reading...

2015, Friday October 23

Letters of Hope

As we already notified in this blog, Embarcadero has been finally bought by IDERA.

Delphi users received a letter from Randy Jacops, IDERA CEO.
Written in my mother language, in perfect French. Nice!

The letter states that they have 20,000 customers...
It sounds more realistic than the numbers usually given for Delphi "users".
Even if it counts for all their tools.
:)

In our forums, we have 1,384 registered users (real humans: we do not accept bots via a Turing test during registration).
It sounds like if Open Source projects are able to gather a lot of users.
And certainly because we maintain support from Delphi 6 up to Seattle (and even Delphi 5 for some part of our libraries)... we have for sure users using FPC/Lazarus (which we also started to support), and others which did not upgrade to the latest Delphi version!

In Randy's letter, the community has a special place.
I hope future of Delphi would see Open Source projects brought by the community as a chance, not as competition.

I'm currently working on a cloud of mORMot servers, serving content coming from high numbers of connected objects.
Object Pascal powered servers, under Windows or Linux (with FPC), are working 24/7 with very low resource use.
A lot of BigData stream is gathered into MongoDB servers, following the CQRS pattern.
It is so easy to deploy those servers (including their high performance embedded SQlite3 database), that almost everyone in my company did install their own "cloud", mainly for testing purpose of the objects we are selling...
Real-time remote monitoring of the servers is very easy and integrated. You could even see the log changing in real-time, or run your SQL requests on the databases, with ease.
When I compare to previous projects I had to write or maintain using Java or .Net, I can tell you that it is "something else".
The IT administrators were speechless when they discovered how it worked: no need of containers, no need of virtual machines (but for infrastructure needs)...
The whole stack is SOA oriented, in an Event-Driven design (thanks to WebSockets callbacks). It follows DDD principles, thanks to the perfect readability of the object pascal language.
Delphi, and Open Source, could be great to create Internet Of Things servers...

2015, Monday August 31

Delphi 10 = DX Seattle is out, mORMot supports it

We expected Delphi XE9, and now we have Rad Studio 10 Seattle, with Delphi renamed as Delphi 10 Seattle, or simply DX.

No big news for the Delphi compiler itself (we are still waiting for Linux server support), but a lot of FireMonkey updates, Windows 10 compatibility enhancements, enhancements to JSON (better performance using a SAX approach), and NoSQL/MongoDB support in FireDAC.
The documentation is rather sparse for the new features, but it goes into the right direction (we support MongoDB since a long time, in our ORM/ODM).
See what's new in details.

Of course, our Open Source mORMot framework supports this version.
Feedback is welcome, as usual!
Enjoy the new DX IDE!

2015, Sunday August 23

"SQL and NoSQL", not "SQL vs NoSQL"

You know certainly that our mORMot Open Source framework is an ORM, i.e. mapping objects to a relational / SQL database (Object Relational Mapping).
You may have followed also that it is able to connect to a NoSQL database, like MongoDB, and that the objects are then mapped via an ODM (Object Document Mapping) - the original SQL SELECT are even translated on the fly to MongoDB queries.

But thanks to mORMot, it is not "SQL vs NoSQL" - but "SQL and NoSQL".
You are not required to make an exclusive choice.
You can share best of both worlds, depending on your application needs.

In fact, the framework is able to add NoSQL features to a regular relational / SQL database, by storing JSON documents in TEXT columns.

In your end-user code, you just define a variant field in the ORM, and store a TDocVariant document within.
We also added some dedicated functions at SQL level, so that SQLite3 could be used as embedded fast engine, and provide advanced WHERE clauses on this JSON content.

Continue reading...

2014, Friday November 28

ODM magic: complex queries over NoSQL / MongoDB

You know that our mORMot is able to access directly any MongoDB database engine, allowing its ORM to become an ODM, and using NoSQL instead of SQL for the query languages.

But at mORMot level, you could share the same code between your RDBMS and NoSQL databases.
The ORM/ODM is able to do all the conversions by itself!
Since we have just improved this feature, it is time to enlighten its current status.

Continue reading...

2014, Friday May 9

BREAKING CHANGE: TSQLRestServerStatic* classes are now renamed as TSQLRestStorage*

From the beginning, server-side storage tables which were not store in a SQLite3 database were implemented via some classes inheriting from TSQLRestServerStatic.
This TSQLRestServerStatic was inheriting from TSQLRestServer
, which did not make much sense (but was made for laziness years ago, if I remember well).

Now, a new TSQLRestStorage class, directly inheriting from TSQLRest, is used for per-table storage.
This huge code refactoring results in a much cleaner design, and will enhance code maintainability.
Documentation has been updated to reflect the changes.

Note that this won't change anything when using the framework (but the new class names): it is an implementation detail, which had to be fixed.

Continue reading...

2014, Wednesday May 7

MongoDB + mORMot benchmark

Here are some benchmark charts about MongoDB integration in mORMot's ORM.

MongoDB appears as a serious competitor to SQL databases, with the potential benefit of horizontal scaling and installation/administration ease - performance is very high, and its document-based storage fits perfectly with mORMot's advanced ORM features like Shared nothing architecture (or sharding).

Continue reading...

MongoDB + mORMot ORM = ODM

MongoDB (from "humongous") is a cross-platform document-oriented database system, and certainly the best known NoSQL database.
According to http://db-engines.com in April 2014, MongoDB is in 5th place of the most popular types of database management systems, and first place for NoSQL database management systems.
Our mORMot gives premium access to this database, featuring full NoSQL and Object-Document Mapping (ODM) abilities to the framework.

Integration is made at two levels:

  • Direct low-level access to the MongoDB server, in the SynMongoDB.pas unit;
  • Close integration with our ORM (which becomes defacto an ODM), in the mORMotMongoDB.pas unit.

MongoDB eschews the traditional table-based relational database structure in favor of JSON-like documents with dynamic schemas (MongoDB calls the format BSON), which matches perfectly mORMot's RESTful approach.

This second article will focus on integration of MongoDB with our ORM.

Continue reading...

Direct MongoDB database access

MongoDB (from "humongous") is a cross-platform document-oriented database system, and certainly the best known NoSQL database.
According to http://db-engines.com in April 2014, MongoDB is in 5th place of the most popular types of database management systems, and first place for NoSQL database management systems.
Our mORMot framework gives premium access to this database, featuring full NoSQL and Object-Document Mapping (ODM) abilities to the framework.

Integration is made at two levels:

  • Direct low-level access to the MongoDB server, in the SynMongoDB.pas unit;
  • Close integration with our ORM (which becomes defacto an ODM), in the mORMotMongoDB.pas unit.

MongoDB eschews the traditional table-based relational database structure in favor of JSON-like documents with dynamic schemas (MongoDB calls the format BSON), which matches perfectly mORMot's RESTful approach.

In this first article, we will detail direct low-level access to the MongoDB server, via the SynMongoDB.pas unit.

Continue reading...

2014, Friday February 28

Are NoSQL databases ACID?

One of the main features you may miss when discovering NoSQL ("Not-Only SQL"?) databases, coming from a RDBMS background, is ACID.

ACID (Atomicity, Consistency, Isolation, Durability) is a set of properties that guarantee that database transactions are processed reliably. In the context of databases, a single logical operation on the data is called a transaction. For example, a transfer of funds from one bank account to another, even involving multiple changes such as debiting one account and crediting another, is a single transaction. (Wikipedia)

But are there any ACID NoSQL database?

Please ensure you read the Martin Fowler introduction about NoSQL databases.
And the corresponding video.

First of all, we can distinguish two types of NoSQL databases:

  1. Aggregate-oriented databases;
  2. Graph-oriented databases (e.g. Neo4J).

By design, most Graph-oriented databases are ACID!
This is a first good point.

Then, what about the other type?
In Aggregate-oriented databases, we can identify three sub-types:

  • Document-based NoSQL databases (e.g. MongoDB, CouchDB);
  • Key/Value NoSQL databases (e.g. Redis);
  • Column family NoSQL databases (e.g. Cassandra).
Whatever document/key/column oriented they are, they all use some kind of document storage.
It may be schema-less, blob-stored, column-driven, but it is always some set of values bound together to be persisted.
This set of values define a particular state of one entity, in a given model.
Which we may call Aggregate.

Continue reading...