Dingsbums 1: Relational Database Management System

Dingsbums 1 (German for thingy) is a small relational database management system written in C and a little C++ for Linux.

I wrote Dingsbums for fun (or educational purposes) in 2006 and 2007; it is not intended for real-world use. It has a relatively wide range of features, but none of them should be expected to be implemented efficiently or stable:

• Relational operators selection, projection, join, union as well as sorting.
• Primary keys and foreign keys, implemented using a B+ tree index structure.
• Views in their most simple form.
• SQL-like language for data definition, manipulation and querying.
• Stored procedures.
• XML-to-relational mapping.
• PHP plugin.

(I also wrote another, equally useless DBMS in Ada, dingsbums 6, in case you're interested.)

Contact: schwering at gmail dot com

Build

# Compile the sources first:
$ make
# Compile the stored proceudres:
$ make sps
# Run a sample file:
$ ./terminal @Queries
# Or could the interactive terminal:
$ ./terminal

Structure

Directories:

• data/ place for database-files, index-files etc.
• db/ core database library written in C
• help/ contains some help files; used by the terminal
• nfa/ parser generator used for the stored procedures parser
• php/ source of the PHP extension
• sp/ standard stored procedures
• xml/ source of the xml-to-relational mapping written in C++

Single files:

• terminal.c the sourcecode of the interactive terminal; compile with make terminal
• test.c shows how to use the db.h interface of the database in C; compile with make test
• spc.c the sourcecode stored procedure compiler; compile with make spc
• Queries sample queries that show most features
• Queries2 sample queries that demonstrate foreign keys

APIs

• db/db.h C interface of dingsbums
• xml/db.hpp C++ wrapper wraps the db.h C functions

Known Bugs

Known bugs:

• FOREIGN KEY to non-existing relation yields Bus Error.
• Stored Procedures: parser is LR(0), should be LR(1) (hadn't read the lecture on compiler construction at the time).
• Stored Procedures: B_LIST to B_LIST.
• Stored Procedures: don't use db.h as interface.
• Stored Procedures: could have a better type system.
• Stored Procedures: relation information function (via io.h).

Wanted optimisations:

• Sorting should use indices. To this end, ixmngt.c needs a function or two to scan an interval (ix_min() and ix_max() from btree.c would help).
• Statistics system: better_xattr() could consider the size of the relation, but then the statistics of the relations need to be stored.
• Query optimiser.

Wanted features:

• Numbers: standard-, minimal-, maximal-values; auto increment.
• Compound indices.
• Something similar to embedded SQL.