View Objec ts and View Links in OAF

View Object (VO) :

• VO's are used where we want some data to be displayed on page.
• VO's are used for just to display data in the page.
• VO access the result set of SQL Statements , it can be either based on EO or Plain Query.
• All VO's end with VO . Example : employeeVO.
• When we create VO one subclass will genrate with setter and getter method.Example: oracle.apps.fnd.framework.OAViewObjectImpl

we have 4 types of View objects.

1. Manual VO.
2. Automatic VO.
3. Validation VO.
4. Property VO.

Manual VO: if we are writing any SQL Query then it will be called Manual VO.

Automatic VO: automatic VO is when we select an EO automatically it will create a select query.

Difference between Automatic VO & Manual VO.

• if we want to perform DML operation then will for Automatic VO , that should be EO based VO.
• we for manual VO if we are using select statement.

Note:  note that when we create VO , all the tables columns will be converted into attributes , hence here we call as attributes.

Validation VO: validating the data in the Database ,example using  WHERE clause in the Select statement.

Property VO:   attributes /columns without database columns comes under property VO. these attributes are also called transient attributes.

Example: Suppose there is a table which holds student marks so therefore it contains 6 columns to hold six subject marks for each student. There is no total column in the table to store the total marks of the student separately. Now in the output for display purpose we are taking TOTAL attribute hence which is not from Data Base table and this TOTAL attribute is called Transient attribute.

View Links (VL):

• Relationship between 2 VO's having one common column in both the VO's called view link.all the VL objects ends with VL. Example : DeptEmpVL

Note that if we want to display Master Detail data then we go for View Links, where as if we want to perform DML operations on Master Detail data we go for Entity Association.

VO interacts with Data Base Directly or VO interacts with Data Base through the EO.