See my Wikipedia link for the proper use of "DB-xx".
The connector Apple used for serial on the 128k through Plus is a DE-9, as often used on PCs.
The connector Apple used on its systems for SCSI is a DB-25. For peripherals Apple used a proper 50-pin micro-ribbon (sometimes called "Centronics") port, including on the PowerCD. (The base has a proper SCSI-1 port.) (Oh, and to wander off on more naming badness, "Centronics" is a company that made parallel-interface printers. Their printers may not have become famous, but their port did. The only proper "Centronics" port is the 36-pin micro-ribbon port used on parallel printers. Yes, the proper name for that style connector is "micro-ribbon". Kind of like how "PS/2" lived on as the name of the keyboard and mouse ports from the such-named computer.)
The connector Apple used for pre-VGA video is a DA-15. (VGA is DE-15, which means it uses an 'E' size shell like a serial port, but crams 15 pins instead of the normal 9. This extra row of pins is sometimes denoted by appending "HD" on the end; which is often also combined with improper use of "DB", making a VGA port improperly called "DB-15HD" to differentiate it from the Apple pre-VGA port being also improperly called "DB-15".)
The connector Apple used for floppy was a custom width, between DA and DB, with 19 pins. So it doesn't even have a proper "Dx-19" name, since there is no letter 'x' to map to its width on the official lists of D-subminiature connectors.