CS558 Database Module.
This module exposes a constructor to the ClassDB object, which handles all of the reading/writing entries in the db. It is built ontop of level.
var classdb = require"cs558-db";//create new ClassDB instancevar db = pathToDataBase;//add a new student to the database with name "name", "password", and a//callback function that is called after the student database operations.//callback will be called with at most one argument -- an error string.dbaddNewStudent"name" "password"iferr//failed to add student to databaseelse//successfully added student to database;//Store student submission sources for each attempt. The callback function//is called with at most one argument -- an error string. Src should be a//Buffer. It is similar usage for putAssignmentScore.dbputAssignmentSrc"name" "password" assignmentNum srciferr//error storing srcelse//successfully store src;//Similarly we can use db to acccess assignment scores and sources, with//db.getAssignmentScore and db.getAssignmentSrc respectively. Takes a//call back as argument, and will be passed an error string as the first//argument if there is an error, otherwise the second argument passed will be//the score(or source for getAssignmentSrc). db.getMaxAssignmentScore is//similar but doesn't take an attempt argument.dbgetAssignmentScore"name" "password" "attempt"iferr//error getting scoreelse//score is read and passed as val;//db.verifyStudent takes a name, password and callback and verifies the//the password name combination, and passes an error to callback if there//is an error.dbverifyStudent"name" "password"iferr//error, maybe non existent student or bad passwordelse//Student identity is verified.;