If a clustered constraint or index already exists on a table, PRIMARY KEY constraints default to NONCLUSTERED. Columns that are of the ntext, text, varchar(max), nvarchar(max), varbinary(max), xml, or image data types cannot be specified as columns for an index. columnIs a column or list of columns specified in parentheses that are used in a new constraint.[ ASC | DESC ] Specifies the order in whi