The binary18 data type

The binary18 data type is a fixed-length opaque data type that holds 18 bytes. Input strings shorter than 18 bytes are right-padded with zeros (00). Strings longer than 18 bytes are truncated.

The binary18 data type has the advantage of not having its length stored as part of the byte stream. When inserting data into the binaryvar data type, the first byte must be the length of the byte array. The binary18 data type does not have this restriction.