Move to referential integrity section:

> 	o Allow DEFERRABLE and end-of-statement UNIQUE constraints?
>
> 	  This would allow UPDATE tab SET col = col + 1 to work if col has
> 	  a unique index.  Currently, uniqueness checks are done while the
> 	  command is being executed, rather than at the end of the statement
> 	  or transaction.
>
<
< * Allow DEFERRABLE and end-of-statement UNIQUE constraints?
<
<   This would allow UPDATE tab SET col = col + 1 to work if col has
<   a unique index.  Currently, uniqueness checks are done while the
<   command is being executed, rather than at the end of the statement
<   or transaction.