DELETE CASCADE and UPDATE CASCADE : CASCADE « Constraints « SQL Server / T-SQL

1. SQL Server / T-SQL
2. Constraints
3. CASCADE

DELETE CASCADE and UPDATE CASCADE

1>
2> CREATE TABLE employee (emp_no    INTEGER NOT NULL  CONSTRAINT prim_empl PRIMARY KEY,
3>                        emp_fname CHAR(20) NOT NULL,
4>                        emp_lname CHAR(20) NOT NULL,
5>                        dept_no   CHAR(4) NULL)
6>
7> CREATE TABLE project   (project_no   CHAR(4) NOT NULL  CONSTRAINT prim_pro PRIMARY KEY,
8>                         project_name CHAR(15) NOT NULL,
9>                         budget FLOAT NULL)
10>
11> CREATE TABLE works_on1
12>             (emp_no INTEGER NOT NULL,
13>              project_no CHAR(4) NOT NULL,
14>              job CHAR (15) NULL,
15>              enter_date DATETIME NULL,
16>              CONSTRAINT prim_works1 PRIMARY KEY(emp_no, project_no),
17>              CONSTRAINT foreign1_works1 FOREIGN KEY(emp_no) REFERENCES employee(emp_no) ON DELETE CASCADE,
18>              CONSTRAINT foreign2_works1 FOREIGN KEY(project_no) REFERENCES project(project_no) ON UPDATE CASCADE)
19>
20> -- The creation of the works_on1 table that uses the ON DELETE CASCADE and ON UPDATE CASCADE options.
21> drop table works_on1
22> GO
1>
2> drop table project
3> drop table employee
4> GO
1>
           
       

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