Databases Reference
In-Depth Information
We will break this acion into the following three parts:
Adding a declaraive validaion
: In this case, the number of employees added to the
department should be greater than five
Specifying the execuion rule
: In our case, the execuion of this validaion should be
fired only for department number
10
Displaying the error message
: We have to show an error message to the user staing
that the number of employees added to the department is less than five
Adding the validation
Following are the steps to add the validaion:
1.
Go to the
Business Rules
secion of
DeptEO.xml
. You will find the
Business Rules
secion in the
Overview
tab.
2.
Select
Enity Validators
and click on the
+
buton. You may right-click on the
Enity
Validators
folder and then select
New Validator
to add a validator.
3.
Select
Collection
as
Rule Type
and move on to the
Rule Deiniion
tab.
4.
In this secion, select
Count
for the
Operaion
field;
Accessor
is the associaion
accessor that gets added through a
composiion associaion
relaionship. Only the
composiion associaion accessor will be listed in the
Accessor
drop-down menu.
Select the accessor for
EmpEO
listed in the dropdown, with
Empno
as the value
for
Atribute
.
In order to create a composition association accessor, you will
have to create an association between
DeptEO.xml
and
EmpEO.xml
based on the
Deptno
attribute with cardinality
of
1 to *
. The
Composition Association
option has
to be selected to enable a composition relationship between
the two entities.
5.
The value of the
Operator
opion should be selected as
Greater Than
.
Compare
with
will be a literal value, which is
5
that can be entered in the
Enter Literal Value
secion below.
Specifying the execution rule
Following are the steps to specify the execuion:
1.
Now to set the execuion rule, we will move to the
Validaion Execuion
tab.
2.
In the
Condiional Execuion
secion, add
Deptno = '10'
as the value for
Condiional Execuion Expression
.
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