Example Input

Schemes: snap$($S$,$N$,$A$,$P$)$ csg$($C$,$S$,$G$)$ cn$($C$,$N$)$ ncg$($N$,$C$,$G$)$ Facts: snap$(\text{'}12345\text{'},\text{'}$C$.$ Brown',$\text{'}12$ Apple St$.\text{'},\text{'}555-1234\text{'}).$ snap$(\text{'}22222\text{'},\text{'}$P$.$ Patty',$\text{'}56$ Grape Blvd$\text{'},\text{'}555-9999\text{'}).$ snap$(\text{'}33333\text{'},$'Snoopy',$\text{'}12$ Apple St$.\text{'},\text{'}555-1234\text{'}).$ csg$(\text{'}$CS$101\text{'},\text{'}12345\text{'},\text{'}$A$\text{'}).$ csg$(\text{'}$CS$101\text{'},\text{'}22222\text{'},\text{'}$B$\text{'}).$ csg$(\text{'}$CS$101\text{'},\text{'}33333\text{'},\text{'}$C$\text{'}).$ csg$(\text{'}$EE$200\text{'},\text{'}12345\text{'},\text{'}$B$+\text{'}).$ csg$(\text{'}$EE$200\text{'},\text{'}22222\text{'},\text{'}$B$\text{'}).$ Rules: cn$($c$,$n$)$ :$-$ snap$($S$,$n$,$A$,$P$),$csg$($c$,$S$,$G$).$ ncg$($n$,$c$,$g$)$ :$-$ snap$($S$,$n$,$A$,$P$),$csg$($c$,$S$,$g$).$ Queries: cn$(\text{'}$CS$101\text{'},$Name$)?$ ncg$(\text{'}$Snoopy$\text{'},$Course,Grade$)?$

Example Output

Rule Evaluation cn$($c$,$n$)$ :$-$ snap$($S$,$n$,$A$,$P$),$csg$($c$,$S$,$G$).$ C$=\text{'}$CS$101\text{'},$ N$=\text{'}$C$.$ Brown' C$=\text{'}$CS$101\text{'},$ N$=\text{'}$P$.$ Patty' C$=\text{'}$CS$101\text{'},$ N$=$'Snoopy' C$=\text{'}$EE$200\text{'},$ N$=\text{'}$C$.$ Brown' C$=\text{'}$EE$200\text{'},$ N$=\text{'}$P$.$ Patty' ncg$($n$,$c$,$g$)$ :$-$ snap$($S$,$n$,$A$,$P$),$csg$($c$,$S$,$g$).$ N$=\text{'}$C$.$ Brown', C$=\text{'}$CS$101\text{'},$ G$=\text{'}$A$\text{'}$ N$=\text{'}$C$.$ Brown', C$=\text{'}$EE$200\text{'},$ G$=\text{'}$B$+\text{'}$ N$=\text{'}$P$.$ Patty', C$=\text{'}$CS$101\text{'},$ G$=\text{'}$B$\text{'}$ N$=\text{'}$P$.$ Patty', C$=\text{'}$EE$200\text{'},$ G$=\text{'}$B$\text{'}$ N$=$'Snoopy', C$=\text{'}$CS$101\text{'},$ G$=\text{'}$C$\text{'}$ cn$($c$,$n$)$ :$-$ snap$($S$,$n$,$A$,$P$),$csg$($c$,$S$,$G$).$ ncg$($n$,$c$,$g$)$ :$-$ snap$($S$,$n$,$A$,$P$),$csg$($c$,$S$,$g$).$ Schemes populated after $2$ passes through the Rules. Query Evaluation cn$(\text{'}$CS$101\text{'},$Name$)?$ Yes$(3)$ Name$=\text{'}$C$.$ Brown' Name$=\text{'}$P$.$ Patty' Name$=$'Snoopy' ncg$(\text{'}$Snoopy$\text{'},$Course,Grade$)?$ Yes$(1)$ Course$=\text{'}$CS$101\text{'},$ Grade$=\text{'}$C$\text{'}$

New Database Operations

Add join and union operations to the Relation class