How to Write a Simple Database Engine

How to write a simple database engine

If you're good at reading code, studying SQLite will teach you a whole boatload about database design. It's small, so it's easier to wrap your head around. But it's also professionally written.

SQLite 2.5.0 for Code Reading

http://sqlite.org/

Implementing a database -- How to get started

First, you may have a look that the answers for How to write a simple database engine. While it focus on a SQL engine, there is still a lot of good material in the answers.

Otherwise, a good project tutorial is Implementation of a B-Tree Database Class. The example code is in C++, but the description of what is done and why is probably what you'll want to look at anyway.

Also, there is Designing and Implementing Structured Storage (Database Engine) over at MSDN. Plenty of information there to help you in your learning project.

Creating a simple database schema

Probably the most important concept to understand before you design your schema (you'll thank yourself for it later, trust me! :-) is that of Normalisation. The tutorial at db.grussell.org doesn't look too shabby and will give you a good grounding. In fact, if you click the "Up One Level" link and take a look around, some of the other information might be quite useful as well.

My "top tip" is: Write it down on paper or in notepad, or anything other than a database, before you start writing code. Get a good idea of what you need your schema to be able to do before you set it in stone (And by "set it in stone" I mean, realise that you've written a load of code against the schema that would have to be re-written if you change it to do what you've just realised you now need).

Writing database software in C/C++

For literature I could recommend something like Accelerated C++ or Thinking in C++. I also recently got my hands on Code Complete, found it in a shelf at work, and it is as good as people say. Solid language agnostic advice.

Also you should separate C and C++, they may seem similar and people clump them together but it's really two different ways of thinking. Now the new C++11 makes the differences even more important to understand, C++ is just not C with classes.

Database engine for a desktop application in C#

Definitely NOT Sql Server Express. That's a server class engine. You want an in-process engine. In that regard, SQLite is fine. So is Sql Server Compact Edition. Both are free and either should be adequate for your needs.

How to build a server database for my application

Arslan's answer is great, but I would like to add to it a bit. You mentioned a Chatroom, so in that case you should look into socket programming. The reason why I bring this up is, while no one has outright said it, you shouldn't create a chat server by read / writing to a database. It's much better to just keep it in memory and log to the database on an as need basis.

AWS is a fantastic solution and they have a lot of different solutions for different situations. You should look at using EC2, which is their server program. They have a free tier of it so that you can use and / or you can test locally. I suggest testing locally then pushing up to a free tier every now and then to make sure everything is running properly.

Also I would look into using CloudKit for data base storage. If you don't need instantaneous communication, it's far easier to use Apple's built in system rather than setup a server and manage it.

links: CloudKit, AWS EC2 Free Tier

As it happens I'm actually working on a ChatRoom Server program, here's the link to github. It is written in C++ so I recommend using it as a reference unless you want to write your own socket in C++.

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