Live sql oracle integrity constraint error, primary key not found - sql

Question

fairly new to sql not sure why this error is coming up, i'm asked to use alter to add columns and foreign key to the animal table referencing the species table species name. i can't figure out a way around this, any help is appreciated. thanks :)
here's my drop tables and create tables query:
DROP TABLE AnimalSale;
DROP TABLE Animal;
DROP TABLE Customer;
DROP TABLE Species;
CREATE TABLE Animal(
animalID NUMBER(4),
animalName VARCHAR2(50),
PRIMARY KEY (animalID)
);
CREATE TABLE Customer(
custID NUMBER(4),
custName VARCHAR2(50),
custEmail VARCHAR2(50),
PRIMARY KEY (custID)
);
CREATE TABLE AnimalSale(
animalID NUMBER(4),
custID NUMBER(4),
PRIMARY KEY (animalID, custID)
);
CREATE TABLE Species(
speciesCode NUMBER(6),
speciesName VARCHAR2(30) UNIQUE,
speciesPrice DECIMAL(5,2),
PRIMARY KEY (speciesCode)
);
My alter query, my lecturer told me the constraint part is wrong but i still couldn't figure out what's wrong and she's not giving me answer :(
ALTER TABLE Animal ADD speciesName VARCHAR2(30);
ALTER TABLE Animal ADD CONSTRAINT fk_species_name FOREIGN KEY (speciesName) REFERENCES Species(speciesName);
Insert table query:
INSERT INTO Animal (animalID, animalName, speciesName) VALUES( '1', 'Tiny', 'Dog');
INSERT INTO Animal (animalID, animalName, speciesName) VALUES( '2', 'Prince', 'Dog');
INSERT INTO Animal (animalID, animalName, speciesName) VALUES( '3', 'CJ', 'Cat');
INSERT INTO Animal (animalID, animalName, speciesName) VALUES( '4', 'Sid', 'Cat');
INSERT INTO Animal (animalID, animalName, speciesName) VALUES( '5', 'Sid', 'Snake');
INSERT INTO Animal (animalID, animalName, speciesName) VALUES( '6', 'Danger', 'Mouse');
INSERT INTO Animal (animalID, animalName, speciesName) VALUES( '7', 'Bonnie', 'Dog');
INSERT INTO Customer (custID, custName, custEmail) VALUES( '1', 'D.Smith', 'dsmith#yahoo.co.uk');
INSERT INTO Customer (custID, custName, custEmail) VALUES( '2', 'B.Bryne', 'bb#gmail.com');
INSERT INTO Customer (custID, custName, custEmail) VALUES( '3', 'X.Dobbs', 'xb#gmail.com');
INSERT INTO AnimalSale (animalID, custID) VALUES( '1', '1');
INSERT INTO AnimalSale (animalID, custID) VALUES( '2', '2');
INSERT INTO AnimalSale (animalID, custID) VALUES( '3', '2');
INSERT INTO AnimalSale (animalID, custID) VALUES( '4', '3');
INSERT INTO AnimalSale (animalID, custID) VALUES( '5', '2');
INSERT INTO Species (speciesCode, speciesName, speciesPrice) VALUES ('1', 'Dog', '9.99');
INSERT INTO Species (speciesCode, speciesName, speciesPrice) VALUES ('2', 'Cat', '10.20');
INSERT INTO Species (speciesCode, speciesName, speciesPrice) VALUES ('3', 'Snake', '20.00');
INSERT INTO Species (speciesCode, speciesName, speciesPrice) VALUES ('4', 'Mouse', '5.00');

Answer 1

i'm asked to use alter to add columns and foreign key to the animal table referencing the species table species name
The error I get when running your script is:
ORA-02291: integrity constraint (FIDDLE_LVXOXDENESSERWXORCJT.FK_SPECIES_NAME) violated - parent key not found
db<>fiddle
To solve it, I just swapped the order of the insert statements so that values were inserted in to the species table before you try to insert values into the animal table so that the foreign key reference can be satisfied.
db<>fiddle
Note: the INSERT statements were wrapped in an anonymous PL?SQL block just for simplicity and so they could all be executed in a single statement; you could equally run each individually.

Answer 2

Ideally, or might be your lecturer wants the animal table's foreign key to refer primary key of species table.
Do this:
ALTER TABLE Animal ADD species_FK NUMBER(6);
ALTER TABLE Animal ADD CONSTRAINT fk_species_id FOREIGN KEY (species_FK) REFERENCES Species(speciesCODE);
In insert, use the speciescode from species table into your animal table's newly added column.
Cheers!!