Some free tools for databases, both for didactic and professional purposes.
Didactic Systems for Databases
The Java Relational System JRS
JRS has been developed at the Computer Science Department of the University of Pisa:
- to practice with SQL, using a simple multi-platform system (for Linux, Mac OS X, Windows),
- to practice with physical plans (access plans), that is how the DBMS executes the queries, as well as with the logical plans, that is how the DBMS translates queries in relational algebra,
- to experiment the effect on the physical plan generated of using different optimization techniques, and different phyical operators,
- to write and execute a query with a graphical editor, defining only a logical plan with the relational algebra, or only a physical plan with the JRS operators,
- to understand the components of a Relational DBMS, by discovering the interfaces among them,
- to experiment with data structures and algorithm to implement a Relational DBMS.
Use the menu on the left to access to all resources relative to JRS.
The Object Database Language Galileo
The Galileo language, develop at the Computer Science Department of the University of Pisa during several research projects, can be found at the link below. The available implementation is somewhat outdated, and probably not working on modern computers. At the link the full documentation about the language can be found.
Web Relational Normalizer
Developed at the Computer Science Department of the University of Venice, can be used to practice the Relational Normalization Theory.
Open Source Systems
The Relational Systems MySQL and MariaDB
MariaDB is a fork of the well-known MySQL system, started after the acquisition of the latter by Oracle Corporation (that maintains a community version of MySQL). Both database systems are very used in web applications, as well as for classical applications. MySQLWorkbench is a graphical interface for MySQL.
The Object Relational System PostgreSQL (formerly Postgres)
PostgreSQL is a well known, powerful, open source, object relational system.
The Relational System Firebird
Firebird is an open source database system derived from Interbase of Borland.
The Relational System MaxDB (formerly SAP DB)
SAP, the produces the ERP system with the same name, has distributed for many years SAP DB as alternative to more renowned commercial systems. In 2000, SAP has published and open system version of it with the name MaxDB. It a relational system that can be used also for OLAP applications.
MonetDB is an open-source system with a data model which is an extension of the relational one, and with both SQL and XQuery as query languages. It has been optimized to be efficient in analytical queries. Data are stored by columns.
Embeddable Relational Systems
SQLite is a open-source, relational system with limited capabilities that can be embedded (as a library) in applications that need to store and manage persistent data as a single file. It is embedded in many systems and devices.
Derby (formerly Cloudscape)
Derby is an open-source relational system written in Java. It can be embedded in Java programs that need to store an manage persistent data.