Whats the benifit of creating table definition manually in informatica (Source Analyzer) instead of importing?

Question

For importing source/target tables, we can either go for importing them from DB/Flat Files/XML Files OR creating the table definition in informatica itself. I have couple of questions here -

• Whats the benifit of creating table definition manually in informatica over importing?
• How can we connect that created table definition to the corresponding data source which could be a DB/Flat file/XML etc.
• Please give a scenario where we create table definitions in informatica rather than importing.

Answer 1

1.There are no "benefits" - It's only an option when you've got the definition, but not the sample. E.g. database object have not been created yet, or are not yet accessible, yet you're starting development already.
2.But the only useful scenario I know is editing - it's far quicker to edit source than import the source if you need to change just length or naming of one column.
3.IMPORTANT NOTE: Source definitions are never connected to any single source instance. This is to represent a structure that will be accessed in future without pointing to any specific table, database, or even server.

Answer 2

• Basically there is no benefit to create table definition manually, even your table contains many columns then it will be time consuming as well.
• Relational Database/Flat Files/ XML all are different, you can't use Relational Database structure to fetch the XML data for that you need to import XML structure only.
• You can create table manually when you don't have privilege to import the structure of the table.