how to create table in ORACLE SQL code example

Example 1: create table oracle

CREATE TABLE ot.persons(
    person_id NUMBER GENERATED BY DEFAULT AS IDENTITY,
    first_name VARCHAR2(50) NOT NULL,
    last_name VARCHAR2(50) NOT NULL,
    PRIMARY KEY(person_id)
);

Example 2: oracle sql create table

/*Deleting whole table with data */
DROP TABLE vehicles;
DROP TABLE owners;

/*First create only this table */
CREATE TABLE owners (
    owner_id NUMBER,
    first_name VARCHAR2(50 CHAR) NOT NULL,
    
    CONSTRAINT owners_pk PRIMARY KEY(owner_id)
);

/* One owner got many vehicles, one to many relation
	or one vehicle got many owners */
CREATE TABLE vehicles (
    vehicle_id NUMBER,
    vehicle_name VARCHAR2(50 CHAR) NOT NULL,
    
  	/* CONSTRAINT vehicle_pk PRIMARY KEY(vehicle_id) --If we had made PRIMARY KEY here it will be one to one relation */
    CONSTRAINT vehicle_owner_fk FOREIGN KEY(vehicle_id) REFERENCES owners(owner_id) ON DELETE SET NULL
);


INSERT INTO owners VALUES(1, 'Abbi');
INSERT INTO owners VALUES(2, 'Beatrix');
INSERT INTO owners VALUES(3, 'Caila');
INSERT INTO owners VALUES(4, 'Dea');
INSERT INTO owners VALUES(5, 'Elise');

INSERT INTO vehicles VALUES(1, 'car');
INSERT INTO vehicles VALUES(2, 'motorcycle');
INSERT INTO vehicles VALUES(3, 'airplane1');
INSERT INTO vehicles VALUES(4, 'airplane1');
INSERT INTO vehicles VALUES(4, 'steamer');
INSERT INTO vehicles VALUES(4, 'submarine');
COMMIT;

DELETE FROM projects WHERE vehicle_id = 4 AND vehicle_name = 'submarine';

/*
Sometimes Oracle SQL Dev don't like this sign ';', 
Primary Key is always NOT NULL UNIQUE,
single PK PRIMARY KEY(user_id), allowed combination:
(1,1) for example (user_id, project_id)
(2,1)
(3,1)
(4,2)

*/  
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