If we create a Page List, in the property rule form, we have the Option source the Data Page, this is available as part of Pega7 Platform. If we leverage this option, there may be chance of Data Replication
For example If the Data Page is <D_Employee>
D_Employee.pxResults(100) – 100 Records , Developer is copying 100 records to Data Page
Pega is copying Data Page to PageList at the back, now the data is available in both of the entities looks like data duplication
If my requirement is to display data then I will prefer Data Page, if it persists with case then I will go by PageList , but not both
If it is parameterized Data Page, it reloads every time when Param changes, this causes the PageList Recopied, but data looks like replication. Here there is no pointers concept like C/JAVA data is available at one Place and refer to this from many places. The same thing happens for Property of Mode Single Page
String Str1 = “Hello World”;
Here String is stored only in one place and str1, str2 refers to same string , no duplicates
Why does Pega introduced this Option. Does this behave like R-D-E (Declare Expression)
"If my requirement is to display data then I will prefer Data Page, if it persists with case then I will go by PageList , but not both"
-In both the cases Data Page can be used.
"Here there is no pointers concept like C/JAVA data is available at one Place and refer to this from many places."
-There is a concept as pointer in PRPC called as 'reference property'. A property can be referenced if 'Allow use as reference property in activities' is selected in advanced tab of the property. And later you can use 'Property-ref' method to relate two properties.
Reference property can be used if you want to relate a property to another property where both properties are in same top-level page or are in different top-level pages. Reference property can be used instead of copying another page.
"Does this behave like R-D-E (Declare Expression)"
Kavileswar, Reference of data page is only like pointers as pointed above. The benefit is you can access the page list using Top or Primary keywords. So defining pages in the pages and classes would be avoided making it easier to access.
Another, benefit of that it does not create two memory instances. The one in the top level page is only reference. You can have a look at the pyAttachmentlist property which refers to a data page on the attachment class.