ERDesignerNG is a Java-based entity relationship design and database modeling tool. It has a powerful WYSIWYG interface for physical database design, supports 2D and 3D database modeling, browsing, and design, handles tables, relations, indexes, and comments, supports a central repository for all models (Model Repository), supports subject areas, supports domains, supports MySQL, Oracle, Microsoft SQLServer, PostgreSQL, and H2, creates the SQL DDL statements for schema creation, has an integrated schema version control system, can generate schema migration scripts for every change, stores the database definition as XML files for further processing, can export the database schema as GIF, BMP, JPEG, or SVG files, has an integrated reverse engineering module for existing schemas, has a build in schema compare feature, can generate schema documentation as PDF, HTML, RTF, and other formats, and supports schema conversion between different dialects.
lib4d_sql is a C library that provides the required functions (connect, prepare, execute, etc.) for writing an SQL client for 4D databases. It uses the public 4D SQL protocol, which is supported by 4D products since version 11. It is already used by the PDO_4D Open Source project, and it might be used to provide others drivers for JDBC, ADO, or ActiveRecord.
nf1db is an in memory database engine with SQL and JDBC interfaces. It supports transactions, commands from the SQL-2003 standard, all major data types, a number of functions, default and null values, auto-increments, constraints, primary and foreign keys, set operations, implicit and explicit joins, nested SELECT statements, quantity limits in SELECT statements, and much more.