how to create categogories in magento or emport and export from database.

Category Creation in magento
Whenever you created category in magento then the created category info will be insert into following tables in magento
1. catalog_category_entity
2. catalog_category_entity_datetime
3. catalog_category_entity_decimal
4. catalog_category_entity_int
5. catalog_category_entity_text
6. catalog_category_entity_varchar
7. catalog_category_flat

remember if you want import category in magento so you simply these these table data export from another database and import whenever you want that its .