1. CS240A:A sample LDL++ Session Carlo Zaniolo Department of Computer Science University of California, Los Angeles December, 2001

2. BSD UNIX whale 206 % which ldl++ /u/class/cs249cz/ldl++/LDL++5.1 whale 208 % pwd /u/f3/zaniolo/recent/cs240a/example whale 209 % ls city.fac city.prg whale 210 % ldl++ ************************************************************************* * LDL++ System (Version 5.1) * etc.... rest of the banner ldl++(1)> ldl++(1)> open city.prg Opening file : city.prg... done.

3. Open—Compile —Close ldl++(2)> compile Compiling all query forms in global module... Error: Free variables in head are not covered in the following unsafe rule: 1 : lcity_ff(C, Popl) _bb 400000. ldl++(3)> close Closing all modules... done. %HERE I EDIT THE PROGRAM ldl++(4)> open city.prg ldl++(5)> compile Compiling all query forms in global module... done.

4. display and initdb ldl++(6)> display export Export in Module [ ldl++_main_module ] : export lcity(X, Y). ** compiled ** export lcity($X, Y). ** compiled ** ldl++(7)> initdb city.fac Initializing database from city.fac... done. ldl++(8)> query lcity(X,Y) Querying : lcity(X,Y)... (Houston, 3000000) (Austin, 750000) (San Antonio, 1500000) The number of records is 3.

5. Command Completion ldl++(1)> e % followed by space edit exit ldl++(1)> exit Exiting LDL++... Good Bye !!