в 13:46, 26 мая 2010

2010-05-26T13:46:06Z

Admin: 1 версия

2010-05-26T10:21:23Z

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==DELETE CASCADE and UPDATE CASCADE==



<source lang="sql">

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>

</source>

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SQL Server/T-SQL/Constraints/CASCADE - История изменений

в 13:46, 26 мая 2010

Admin: 1 версия