Compressed databases can include compressed and uncompressed tables or partitions.
create database database_name […] with dml_logging = { minimal | full } , durability = { no_recovery | at_shutdown | full } , compression = {none | row | page}
The compression = parameter indicates that all tables in the database inherit the specified level of compression, unless you explicitly state otherwise. See the Reference Manual: Commands.
create database emaildb on emaildb_dev = '50M' with compression = row