A relational schema, normalized to at least third normal form $(3$NF$)$

EMPLOYEE $($EMPLOYEE$\_$ID$,$ EMPLOYEE$\_$FIRSTNAME, EMPLOYEE$\_$LASTNAME, EMPLOYEE$\_$SALARY, EMPLOYEE$\_$TYPE, EMPLOYEE$\_$ADDRESS, EMPLOYEE$\_$EMAIL, EMPLOYEE$\_$PHONE$)$

MANAGER $($EMPLOYEE$\_$ID$,$ MANAGER$\_$ID$,$ MANAGER$\_$TYPE, MANAGER$\_$ADDRESS, MANAGER$\_$ZIPCODE, MANAGER$\_$PHONE, NUM$\_$EMPLOYEES$)$

INSTRUCTOR $($EMPLOYEE$\_$ID$,$ INSTRUCTOR$\_$CERTIFICATION, NUM$\_$CLASSES, INSTRUCTOR$\_$ADDRESS, INSTRUCTOR$\_$ZIPCODE, MANAGER$\_$ID$)$

EQUIPMENT $($EQUIPMENT$\_$ID$,$ EQUIPMENT$\_$NAME, EQUIPMENT$\_$SOURCE, SOURCE$\_$EMAIL, EQUIPMENT$\_$COST, EQUIPMENT$\_$NUM, EMPLOYEE$\_$ID$)$

MEMBER $($MEMBER$\_$ID$,$ MEMBER$\_$FIRSTNAME, MEMBER$\_$LASTNAME, MEMBER$\_$AGE, MEMBER$\_$ADDRESS, MEMBER$\_$EMAIL, MEMBER$\_$PHONE, MEMBER$\_$GENDER, MEMBER ZIPCODE, EMPLOYEE$\_$ID$)$

ENROLLMENT $($MEMBER$\_$ID$,$ CLASS$\_$ID$,$ CLASS$\_$ENROLL$\_$DATE$)$

CLASS $($CLASS$\_$ID$,$ CLASS$\_$NAME, CLASS$\_$TIME, CLASS$\_$SIZE, CLASS$\_$DATE, EMPLOYEE$\_$ID$)$

MEMBERSHIP $($MEMBERSHIP$\_$ID$,$ MEMBERSHIP$\_$TYPE, MEMBERSHIP$\_$SIGNDATE, MEMBERSHIP$\_$RENEWAL, MEMBERSHIP$\_$COST, MEMBER$\_$ID$)$