Periodic Table Database - Build a Periodic Table Database

prodseis · November 3, 2023, 1:51am

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Describe your issue in detail here.
I am unable to set the type_id column as NOT NULL, i tried everything i know. I tried deleting it and adding it again setting it as INT NOT NULL but it didint work, so i just created the column as INT, then updating the column with the NOT NULL data type. Every time i try, terminal says it contains null values however i havent added any values yet into any columns. I tried setting every column as not null of every table but it didnt work. I dont know what else i can do. Ill leave a link to my git repository where i have written down every bash command along with the comment/task for what the command was oriented.

Your code so far

github.com

prodri69/periodic-table/blob/main/bash

#Part 1: Fix the database

#You should rename the weight column to atomic_mass
ALTER TABLE properties RENAME COLUMN weight TO atomic_mass;

#You should rename the melting_point column to melting_point_celsius and the boiling_point column to boiling_point_celsius
ALTER TABLE properties RENAME COLUMN melting_point TO melting_point_celsius;
ALTER TABLE properties RENAME COLUMN boiling_point TO boiling_point_celsius;

#Your melting_point_celsius and boiling_point_celsius columns should not accept null values
ALTER TABLE properties ALTER COLUMN melting_point_celsius SET NOT NULL;
ALTER TABLE properties ALTER COLUMN boiling_point_celsius SET NOT NULL;

#You should add the UNIQUE constraint to the symbol and name columns from the elements table
ALTER TABLE elements ADD CONSTRAINT unique_symbol UNIQUE (symbol);
ALTER TABLE elements ADD CONSTRAINT unique_name UNIQUE (name);

#Your symbol and name columns should have the NOT NULL constraint
ALTER TABLE elements ALTER COLUMN symbol SET NOT NULL;
ALTER TABLE elements ALTER COLUMN name SET NOT NULL;

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Periodic Table Database - Build a Periodic Table Database

prodseis · November 3, 2023, 2:09am

I solved it by setting a default value of 1 after setting it as not null, line of command was "ALTER TABLE properties ADD COLUMN type_id INT NOT NULL DEFAULT 1 REFERENCES types(type_id);