CREATE TABLE table_6315 ("Model" TEXT, "Codename" TEXT, "Capacities  ( GB ) " TEXT, "NAND type" TEXT, "Interface" TEXT, "Form factor" TEXT, "Controller" TEXT, "Seq. read/write MB/s" TEXT, "Rnd 4KB read/write IOPS  ( K ) " TEXT, "Introduced" TEXT)

Which interface uses Sandforce with a code name of Sierra Star?
SELECT "Interface" FROM table_6315 WHERE "Controller" = 'sandforce' AND "Codename" = 'sierra star'
SELECT "Interface" FROM "table_6315" WHERE "Codename" = 'sierra star' AND "Controller" = 'sandforce'