How do I fix a ORA-00902: invalid datatype creating a table - sql

Question

I am creating a table in a command SQL sections into a script already populated I have created several tables already but in this one I get a message saying
ORA-00902: invalid datatype
CREATE TABLE Weapons
(
id NUMBER(4),
name VARCHAR2(30),
damage NUMBER(4),
company_id VARCHAR2 (10),
CONSTRAINT pk_Weapons PRIMARY_KEY(id),
CONSTRAINT fk_Weapons_company
FOREIGN_KEY(company_id) REFERENCES Company(id),
CONSTRAINT fk_Weapons_ammo
FOREIGN_KEY(ammo_id) REFERENCES Ammo(id)
);

Answer 1

In the CONSTRAINT, it should be FOREIGN KEY and not FOREIGN_KEY. Also it should be PRIMARY KEY, not PRIMARY_KEY.
There is no underscore required as per syntax. So the query will be:
CREATE TABLE Weapons (
id NUMBER(4),
name VARCHAR2(30),
damage NUMBER(4),
company_id VARCHAR2(10),
CONSTRAINT pk_Weapons PRIMARY KEY(id),
CONSTRAINT fk_Weapons_company FOREIGN KEY(company_id) REFERENCES Company(id),
CONSTRAINT fk_Weapons_ammo FOREIGN KEY(ammo_id) REFERENCES Ammo(id)
);
About Foreign Keys: https://www.techonthenet.com/oracle/foreign_keys/foreign_keys.php
About Primary Keys: https://www.techonthenet.com/oracle/primary_keys.php

Answer 2

Here's a working example. I've created the AMMO table (whose description you didn't post, so I used only the ID column so that the foreign key constraint wouldn't fail). Pay attention to comments I wrote within the code.
SQL> create table ammo
2 ( id VARCHAR2(10),
3 CONSTRAINT pk_ammo PRIMARY KEY(id) );
Table created.
SQL> CREATE TABLE Company
2 ( id VARCHAR(3),
3 name VARCHAR(30), --> switch from CHAR to VARCHAR2
4 CONSTRAINT pk_Company PRIMARY KEY(id) );
Table created.
SQL> CREATE TABLE Weapons
2 ( id NUMBER(4),
3 name VARCHAR2(30),
4 damage NUMBER(4),
5 company_id VARCHAR2(3), --> should match COMPANY.ID datatype
6 ammo_id VARCHAR2(10), --> should match AMMO.ID datatype
7 CONSTRAINT pk_Weapons PRIMARY KEY(id),
8 CONSTRAINT fk_Weapons_company FOREIGN KEY(company_id) REFERENCES Company(id),
9 CONSTRAINT fk_Weapons_ammo FOREIGN KEY(ammo_id) REFERENCES ammo(id) );
Table created.
SQL>
In referential integrity constraint, you should match datatypes of the foreign and primary key columns. There's no sense in having a VARCHAR2(10) in the detail table which points to a VARCHAR2(3) column in the master table; you won't be able to put anything longer than 3 characters into the detail table's column anyway (foreign key constraint won't let you).