Simple DB system to store data

HI, id like a online system where i can upload data ( email:pass) and its stored into a DB, and when i need to update data, i just import a txt containing email:newpass and system automatically update new pass.

2- Need to download data when i need as txt with format (email:pass)

3- need a area to delete invalid emails:pass, so i import email:pass and DB deletes this data.