The BIT data type holds a variable length string of binary
digits. It is commonly used to represent arbitrary binary data that
does not contain an exact number of bytes. A bit string literal consists
of the letter B, followed by a string of binary digits enclosed in
single quotation marks, as in the following example:
B'0100101001'
Any
number of digits, which must be either 0 or 1, can be specified. The
initial B can be specified in uppercase or lowercase.