Sql foreign key

Alter table add column and foreign key mysql

ALTER TABLE database.table
  ADD COLUMN columnname INT DEFAULT(1),
  ADD FOREIGN KEY fk_name(fk_column) REFERENCES reftable(refcolumn) ON DELETE CASCADE;

Source: stackoverflow.com

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

Sql foreign key

create table Jobs(
job_id number not null,
job_title varchar(30),
min_salary number,
max_salary number
);
create table job_history(
employee_id number not null,
start_date date,
end_date date,
job_id number not null,
department_id number
);
alter table jobs add constraint pk_jobs primary key(job_id);
alter table job_history add constraint fk_job foreign key(job_id) references jobs(job_id);

Foreign key in sql dbms

FOREIGN KEY (fk_col_name) 
REFERENCES target_table_name (pk_col_name);

Source: launchschool.com

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

6 votes210 views2 answers
Oracle compile trigger
SQL
3 votes166 views4 answers
Order by desc postgres
SQL
2 votes178 views1 answer
Illuminate\Database\QueryException : SQLSTATE[HY000] [1698] Access denied for user 'root'@'localhost'
SQL
0 vote196 views1 answer
Oracle chain step succeeded
SQL
0 vote193 views1 answer
Download sql file of countries names
SQL
1 vote131 views2 answers
Last working day in week date function in sql
SQL
0 vote200 views1 answer
Get only one row in mysql
SQL
4 votes163 views1 answer
Datepart postgres
SQL
0 vote184 views1 answer
Template MySQL Zabbix agent
SQL
10 votes169 views1 answer
Oracle view dependencies
SQL