Defining primary and foreign keys

A very important concept of relational databases is the use of primary and foreign keys. In this exercise, you will define a two new tables. A table Person, with a PRIMARY KEY and another table, History, with a PRIMARY KEY and a FOREIGN KEY referencing the Person table.

Latihan ini adalah bagian dari kursus

Hierarchical and Recursive Queries in SQL Server

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Petunjuk latihan

Define the primary key PersonID for Person of type INT.
Define the primary key OrderID for History.
Define the foreign key PersonID referencing the primary key of Person.

Latihan interaktif praktis

Cobalah latihan ini dengan menyelesaikan kode contoh berikut.

CREATE TABLE Person (
  	-- Define the primary key for Person of type INT
  	___ ___ NOT NULL ___ ___,
	Firstname VARCHAR(255) NOT NULL,
	Lastname VARCHAR(255) NOT NULL,
);

CREATE TABLE History (   
    -- Define the primary key for History
  	OrderID INT ___ ___ ___ ___,
    Item VARCHAR(255) NOT NULL,
    Price INT NOT NULL,
  	-- Define the foreign key for History
    PersonID INT ___ ___ REFERENCES Person(___)    
);

SELECT * 
FROM History;

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