Free database software for linux

Valentina is cross-platform DBMS that makes it easy to switch between a local embedded database and server using the same sources. It supports disk and in-memory databases, field types from Bit to BLOB, and both a SQL92(99) and non-SQL API.
Valentina supports Relational, Extended Navigational, and Object-Relational data models. It introduces a revolutionary model abstraction "Link". It works natively in UTF-16, can accept 270 encodings, and features advanced features such as regular expressions, XML, full-text search, pictures, functions, and calculated fields. It offers triggers, views, and stored procedures.
Enhancements:
- Valentina Studio now has a Diagrams panel for database schema.
- There are new examples on the usage of Link refactorings API and SQL commands.
- There are about 40 bugfixes over the entire product line (kernel, PHP, REALbasic, Director, VCOM, and VStudio).

Generator is an command line application written in java that have the goal to make easy the construction of little applications that needs some database objects stuff.
Database Bean Generator isnt a replacement of complex object persistence solutions, like hibernate or TopLink but it covers a different target. The little java web applications that dont use sofisticated persistence options.
Generator invocation is simple, just type:
java -jar generator.jar -xml (config-file.xml)
where config-file is a xml config file with the definitions to connect to the database and generate the bean classes.
Main features:
- Generates classes to access via custom connection resources to database tables.
- Configuration files are in clear xml format and can be embedded or separate.
- Supports individual or global field updates.
- Supports custom set of Exceptions.
- Provides toXML function for each entity generated.
- Provides automatic generation of finders coonfigured in the xml configuration file.
- Provides some utility static methods via the BdUtils.java class generation.
- Generates an xml file with the database structure.
- Supports configuration of the methods that produces XML (String as CDATA, data as attributes or values, ...)
- Initial support for MySQL and Oracle (Oracle support is in initial stage at this moment).
- Provides an ant task for automatic integration builds.
- Supports transparent renaming of the generated class individual fields.
- Supports normal or CDATA output in individual fields.
- Supports utilization in all database methods with your own external connection.
- Preliminar support of a pluggable logging system (The goal is use log4j integration)
- Support for SEQUENCES in Oracle and AUTOINCREMENT in MySQL
- Support arbitrary raw code and imports from configuration file
- Correct treatment for NULL values of the fields in the generated class
Enhancements:
- Optionally, you may include the extra jars to get JSON support.
- JSON output for finders and generic JSON output for general have been added.

Database Functions is a PHP class that can be used to build and execute MySQL database queries.

It can build SELECT, INSERT, UPDATE and DELETE queries from lists of parameters and values.

The class can also execute the generated queries and retrieve the SELECT query results into associative arrays.

phpCodeGenerator is a free database driven website code generator. This application reads the database and generates a website with the ability to Create, List, Edit, Update, Delete and Search Records.

sqlupdate reads a MySQL table declaration file and compares it to an existing database. sqlupdate project then generates a MySQL script for updating the database to match the SQL file.