Adding a Check Constraint

Creating and Using Tables

3-12 Oracle Database 2 Day Developer's Guide

REFERENCES "HR"."PERFORMANCE_PARTS" ("PERFORMANCE_ID") ENABLE

, you will create a foreign key constraint on the

evaluations

table by

entering the required information directly in the SQL Statement window.

Example 35 Adding a Foreign Key Constraint in SQL Script

ALTER TABLE evaluations

ADD CONSTRAINT eval_emp_id_fk FOREIGN KEY (employee_id)

REFERENCES employees(employee_id);

The results of the script follow.

ALTER TABLE evaluations succeeded

You have now created a foreign key constraint on the

employee_id

column from the

employees

table. If you click the SQL tab, you will see the following SQL statement

was added to your table definition. You may need to click the Refresh icon.

CONSTRAINT "EVAL_EMP_ID_FK" FOREIGN KEY ("EMPLOYEE_ID")

REFERENCES "HR"."EMPLOYEES" ("EMPLOYEE_ID") ENABLE

To add a check constraint using the SQL Developer interface:

You will add a check constraint to the

scores

table using the SQL Developer

graphical interface. You could also use the Edit Table window, as in the

NOT NULL

constraint, to accomplish this task.

In the Connections navigation hierarchy, the plus sign (+) next to Tables to expand
the list of tables.

Right-click the

scores

table.

Select Constraint, and then select Add Check.

In the Add Check window, enter the following information:

Set the Constraint Name to

SCORE_VALID

Set Check Condition to

score >=0 and score <=9

Set Status to

ENABLE

Click Apply.