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

8 votes242 views1 answer
Show mysql user table
SQL
1 vote227 views1 answer
Sql select where id not exists in another table
SQL
0 vote286 views2 answers
Sql unique
SQL
10 votes229 views4 answers
Mysql one week ago
SQL
0 vote254 views1 answer
Providername system.data. mysql
SQL
1 vote198 views1 answer
Into sql
SQL
3 votes228 views2 answers
Sqlite show table definition
SQL
4 votes244 views1 answer
Data types in sql
SQL
1 vote242 views1 answer
Postgresql pass array in function
SQL
2 votes271 views2 answers
Null column to 0 in mysql
SQL