I'm creating a rudimentary database to get the hang of Oracle syntax, but am having issues flushing out an error I am receiving (SQL Error: ORA-00904). Attached is some source with description: Code (SQL): CREATE TABLE tblEmployee ( EmployeeID INTEGER NOT NULL, EmpFName VARCHAR2 (25) NOT NULL, EmpLName VARCHAR2 (25) NOT NULL, EmpSSN VARCHAR2 (12) NOT NULL, JobTitle VARCHAR2 (25), ADD CONSTRAINT "tblEmployee_pk" PRIMARY KEY (EmployeeID) ); CREATE TABLE tblStation ( StationID INTEGER NOT NULL, StationDescr VARCHAR2(50), ADD CONSTRAINT "tblStation_pk" PRIMARY KEY (StationID) ); CREATE TABLE tblShift ( ShiftID INTEGER NOT NULL, DayofWeek CHARACTER(3), StartTime DATE, EndTime DATE, ADD CONSTRAINT "tblShift_pk" PRIMARY KEY (ShiftID) ); CREATE TABLE tblEmployeeSchedule ( AssignmentID INTEGER NOT NULL, EmployeeID INTEGER NOT NULL, StationID INTEGER NOT NULL, ShiftID INTEGER NOT NULL, ADD CONSTRAINT "tblEmployeeSchedule_pk" PRIMARY KEY (AssignmentID), ADD CONSTRAINT "tblEmployeeScheduleEmployee_fk" FOREIGN KEY (EmployeeID), ADD CONSTRAINT "tblEmployeeScheduleStation_fk" FOREIGN KEY (StationID), ADD CONSTRAINT "tblEmployeeScheduleShift_fk" FOREIGN KEY (ShiftID) ); COMMIT; Within every table creation function, I am getting the error: Error report: SQL Error: ORA-00904: : invalid identifier 00904. 00000 - "%s: invalid identifier" *Cause: *Action: committed. This is frustrating because I am not clear on what part of my syntax is incorrect. Is there something that needs to be Oracle specific in there? Searching the error reveals several possible causes which leads me here. Also, there is a nondescript error starting at my CREATE TABLE tblEmployee function.