Database development

Java

.NET

Software development

Web development

XML

Oracle

Oracle Application Express (HTML DB)

Oracle SQL Developer

Toad for Oracle

Oracle SQL Developer Data Modeler

Free DBMSs

IBM DB2 Express-C

SQL Server 2008 Express Edition

SQL Server 2008 Express Edition with Advanced Features

MySQL

Oracle 10g Express Edition (XE)

db4o - OO

MySQL

Java driver

docs 5.0, 5.1

Microsoft SQL Server

Management Studio Express (2005)

Microsoft SQL Server Database Publishing Wizard 1.1 - included in VisualStudio 2008 - tutorial

Java driver

Microsoft T-SQL

MSDN - TSQL reference

DevGuru TSQL charts

DevGuru TSQL quick reference

Data

Freebase - public databases

GeoNames - reverse geolocator

OpenCalais - structured data

Free database tools

SQuirreL (JDBC based)

SQLyog - MySQL

db4o

db4o

Generic Repository example

Biofractal blog

with StructureMap - singletons