datalog - Man Page

a lightweight deductive database system


datalog [Options] [FILE]


The datalog program provides a lightweight deductive database system.  Queries and database updates are expressed using Datalog-a declarative logic language in which each formula is a function-free Horn clause, and every variable in the head of a clause must appear in the body of the clause.  The use of Datalog syntax and an implementation based on tabling intermediate results, ensures that all queries terminate.  The program reads and executes the assertions and queries in FILE, or enters interactive mode if an input file is not given.



Send output to a file (default is standard output).


Enter interactive mode after loading input file.


Load extensions written in Lua.


Print output as tab separated values.


Display command usage info.


Display command version info.

Exit Status

The exit status is non-zero if there is a syntax error in the input file or an internal error is detected.

See Also

The full documentation for datalog is maintained as a Texinfo manual. If the info and datalog programs are properly installed at your site, the command

info datalog

should give you access to the complete manual.


Jan 2012