Loading data from Flat files

Scenario:

1. I have to load data into oracle from multiple large flat flies and XML.
2. Each flat file contains data of multiple table.
3. Structure of flat file is like this

system_variable TableName:Column1_Name="Value", Column2_Name="Value", Column3_Name="Value".......................ColumnN_Name="Value";

4. Only Changed/Added columns are available in file for that particular table.

 Question: What is the best method to load data from these files to Oracle tables?

Regards
Abhishek Gurung                                                

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