Foreign keys

CREATE TABLE Employee(
    EmployeeID int NOT NULL,
    LastName varchar(50) NOT NULL,
    FirstName varchar(20) NOT NULL,
    Age int,
    DeptNo int,
    PRIMARY KEY (EmployeeID),
    FOREIGN KEY (DeptNo) REFERENCES Department(DeptNo)
);

Foreign key

USE Organization
CREATE TABLE Employee_Office
(
Id INT PRIMARY KEY IDENTITY(1,1),
Emp_Id int FOREIGN KEY REFERENCES Employee(Id),
Office_Id int FOREIGN KEY REFERENCES Office(Id)
)

Source: codingsight.com

What is foreign key

Foreign Key: 
It is a column that comes from a different table and
using Foreign key tables are related each other
It is the primary key of another table
It can be duplicate or null for another table

Foreign key

CREATE TABLE Employee(
    EmployeeID int NOT NULL,
    LastName varchar(50) NOT NULL,
    FirstName varchar(20) NOT NULL,
    Age int,
    DeptNo int,
    PRIMARY KEY (EmployeeID),
    FOREIGN KEY (DeptNo) REFERENCES Department(DeptNo)
);

Source: computerscienceai.com

Foreign key

USE Organization
CREATE TABLE Employee
(
Id INT PRIMARY KEY IDENTITY(1,1),
Name VARCHAR (50) NOT NULL,
Age INT,
Gender VARCHAR (50),
Dep_Id int FOREIGN KEY REFERENCES Department(Id),
Insur_Id int FOREIGN KEY REFERENCES Insurance(Id)
)

Source: codingsight.com

Similar codes

0 vote328 views1 answer
How to put is null in where in clause
SQL
0 vote363 views1 answer
Load data infile mariadb slow
SQL
0 vote376 views1 answer
GROUP BY postgres
SQL
7 votes341 views3 answers
Sql fill table with info from anothe rtable
SQL
0 vote318 views1 answer
How to connect to mysql in ef 6
SQL
0 vote318 views1 answer
Postgres select except
SQL
0 vote329 views1 answer
Pip install mysqlclient error
SQL
10 votes299 views1 answer
Oracle view dependencies
SQL
0 vote325 views1 answer
Jooq replace
SQL
0 vote408 views1 answer
Add two days to current date in sql when creating tables
SQL