I have sheet where I write books and informations like writers, pages, reading duration, reviews, etc. What I want is to create writers database in a new sheet. When I add a new book and writer, it would add the writer to the database but with no duplicate. Any suggestions how to do it?
[Re-Titled by Moderator]
MacBook Air 13″, macOS 12.6
In the iOS version of Numbers you can create forms for data entry. Not so in the Mac OS version. But, even ,then, it will not prevent duplicates.
A spreadsheet can be used as a rudimentary database but it really isn't a database app, just a table of records (i.e., rows of data in a spreadsheet) with some crude/minimal ways to find and display the data. Your database table will need columns for all related information including writer, pages, duration, and so on. You will enter your data in this table (not the other one), one row per record. You can use categorization to view the data directly in this table or you can set up filters or you can use another table/sheet to do some rudimentary lookups from the database table. All data entry and any changes must be made directly in the database table, you cannot enter data or make changes from any other table. It is all very crude compared to a real database app.
How to create a database of writers with no duplicates in Numbers
