This is Maven
It's like CocoaMySQL.
Only, it's also for PostgreSQL & SQLite3.

Access three Database Systems using one single interface.
Drag and drop Table and Field structures between them.
Download Maven.zip now. It's free.

• Querying the Database
• Copying Table & Fields from one database to another

Sample Objective-C source code
This simple example illustrates how to access three database systems in the same uniform way from Objective-C code. With just two calls, lookup and execute, it's possible already to do quite a lot of stuff with the database you create using Maven.

I've used quite a bit more convenience methods in the actual source code for Luca and Maven, but this is the basic structure. It's useful for starters and I will make more of the code available as I build on this example.

About Maven by Bernard Teo
When I was developing Luca, I kept finding that I needed a way to quickly experiment with the structure of the database, and I'd rather work with a GUI because I want to focus on the needs of Luca rather than be distracted by wondering what commands I need to issue to make the database do what I want it to do. And I needed an interface that will work the same, whether I'm working with MySQL or PostgreSQL or SQLite3, which are the databases Luca currently supports.

So, I thought I would re-organise the database access frameworks that I had been building to access MySQL, PostgreSQL and SQLite3, so that they present one consistent programming interface to my Cocoa application, and then use that to build what I call Maven, as a visual representation of what can be achieved. And so far, I'm surprised that it's possible, though it was hard, but I did get it up to here, and it did make programming Luca easier, to deal with all these databases, and any more that I hope to add in the future. I'll try to document the programming interface to these frameworks so that others can use them, too.
Maven assumes that you have MySQL or PostgreSQL installed.
If not, download and install them from :

• MySQL installer (from mysql.com)
• PostgreSQL installer (from Marc Liyanage's very excellent site)

The latest version of Maven is 0.5.2 Beta
This version fixed a couple of bugs, 1) with deleting MySQL databases, and 2) with handling decimal numbers greater than 10,000,000.

Things To Do :
1) Drag and drop table contents across databases, even of different types
2) Support for compound keys
3) Move on to build the search, filtering and query building tools.