"It would be nice to have everything (attendance, hw, classwork, test, quiz etc) all in one record so that I can make a comment for one student's classwork and change another student who just shows up as tardy in attendance on the same screen."
I suggest you keep the concept of "all on one screen" separate from "all in one table". ;-)
The first is an interface design concept that controls how you view and edit data. The second is a concept that will greatly affect how you can link different data together. It's possible to combine data from multiple tables into a single layout to give you your "all in one screen" and I think this is what you want here. You can use portals and tab controls to control how these fields are made available to you for this purpose. You might, for example, have one tab on your screen that uses a portal to list the class roster for attendance. A second can list assignments in a portal and a third can be used for your behavior scores.
I suggest yet another table for your behavior scores. At the risk of comitting heresy, I think you might use a repeating field of individual scores for a given student and use calculation fields that use functions such as Sum and average to compute a daily total or average behavior score for a given student.
I understand the difference between the tables and the layout/interface, but setting up another table with multiple related records would likely require more than one portal (or more than one line per student) and I was hoping to get everything to be on one line for each student.
When you say to use "a repeating field of individual scores for a given student and use calculation fields that use functions such as Sum and average to compute a daily total or average behavior score for a given student" are you suggesting to actually create a few fields such as comment1, comment2, comment3,... in the table, or are you suggesting to use the option in field options to add repeating or recurring fields.
I didn't think of this before, but I suppose I could also create a button (on the assignment or attendance screen) to create records in a related table of comments and then I would be able to add unlimited comments. Then, it's on the same screen and no separate portal required either.
I'm getting the picture that I should also have different tables for the homework (check boxes) and tests/quizzes (numeric).
I used to use an ancient version of FileMaker for tracking student grades when I was trying to be a teacher. Come to think of it, that was the very first FileMaker database I ever created! If I were creating such a DB today, I'd use one table for all homework, tests and assignments. I might even include the behavior scores as a type of "assignment" as well. That's to make computing grades less complicated. You can distinguish between types by adding a field in the record definition that is used to identify a given score as Homework, Test, etc. This field can then be used in portal filters, sort orders and also in subsummary reports to control how the records in this table are displayed and organized.
On repeating fields: Yes, I was describing the field option. This is a very ancient FileMaker feature that has only limited utility today as tables of repeating records are almost always a better design choice. One of the remaining advantages to using this feature is that it is easier to set up a horizontal row of fields for some data-entry tasks--especially if you do not need to do much with the individual data points--just an aggregate such as a total or average.
I'm Picturing this for your behavior scores data entry:
student name: BScores 1 | 2| 3| 4| ..... 10| Total: Ave:
Where each of the columns to right of the student's name is a different repetition of the Bscores table.