The DQ_DEF extension contains the bit assignments used in the DQ array.
It contains the following 4 columns:

===========  =======  ===============================================
TTYPE        TFORM    Description
===========  =======  ===============================================
BIT          integer  The bit number, starting at zero
VALUE        integer  The equivalent base-10 value of BIT
NAME         string   The mnemonic name of the data quality condition
DESCRIPTION  string   A description of the data quality condition
===========  =======  ===============================================

**NOTE:** For more information on standard bit definitions see: :ref:`Data Quality Flags`.


