It doesn't support MySQL? strange. How about PostgreSQL?
Flat text files are OK, but keep in mind that unless you come with something really sophisticated you should keep it rather small. Flat text files are just that: text files. Usually you write the data line by line using some given separator - each line is a row. No indexing or simple indexing at best (that means no complicated queries get done fast). No compression.
If you plan to stick to plain text, use CSV (comma separated values - importable/exportable from/to excel, access, openoffice, mySQL, Oracle, etc). Just store the column names in the first line, separated by commas, and in the following lines do the same with every row (values).