PeopleSoft Technical person knows how to code in PeopleSoft to execute the requirement.
PeopleSoft Functional person knows the Domain i.e the Customer Business, user processes and maps them to PeopleSoft and performs the rule and the Configurations required and collects the requirement and decides what is customization or what is delivered by PeopleSoft.
PeopleSoft Techno Functional person is having the knowledge of both technical as well of Functional role. But todays world considers who ever knows peoplesoft Coding as well the Configuration in PS is a Technofunctionl person.

To migrate from legacy:
-> Identify the fields to be extracted from legacy
-> Map the legacy fields to peoplesoft fields.create the new fields if needed
-> Apply the business logics and get the legacy data to peoplesoft using PeopleSoft tools such as AE/CI

PSCAMA contains fields common to all messages. The <PSCAMA> tag repeats for each row in each level of the <Transaction> section of the message.
The sender can set PSCAMA fields to provide basic information about the message

The SQl statements are used to fetch/retrieve, update, insert, delete data from the database. In PeopleSoft we use the sql stmts using sqlexec or createsql.Differnet sql statements are:Select, Insert, Update, Delete.
Metasql statement->
Differnet RDBMS have differne date and time formats. though the component processor takes care of the automatic convesion but at the time of using the sqlexec the automatic conversion does not take place. So in order to understand this the meta sql concept has come. Whcih we can use in diff sql stmts. for example %datetimein, %date, %time, %currentdatetime,  %datetimeout etc.
%dateIn: This is used in the where caluse of "Select and update"
%dateout: This is used while selecting the data.