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Update reference documentation on may/can/might:

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Standard English uses "may", "can", and "might" in different ways:

        may - permission, "You may borrow my rake."

        can - ability, "I can lift that log."

        might - possibility, "It might rain today."

Unfortunately, in conversational English, their use is often mixed, as
in, "You may use this variable to do X", when in fact, "can" is a better
choice.  Similarly, "It may crash" is better stated, "It might crash".
This commit is contained in:
Bruce Momjian
2007-01-31 23:26:05 +00:00
parent bc799fab2b
commit e81c138e18
71 changed files with 301 additions and 301 deletions
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12
doc/src/sgml/ref/create_index.sgml
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@@ -1,5 +1,5 @@
<!--
$PostgreSQL: pgsql/doc/src/sgml/ref/create_index.sgml,v 1.59 2007/01/09 02:14:10 tgl Exp $
$PostgreSQL: pgsql/doc/src/sgml/ref/create_index.sgml,v 1.60 2007/01/31 23:26:03 momjian Exp $
PostgreSQL documentation
-->
@@ -75,7 +75,7 @@ CREATE [ UNIQUE ] INDEX [ CONCURRENTLY ] <replaceable class="parameter">name</re
</para>
<para>
The expression used in the <literal>WHERE</literal> clause may refer
The expression used in the <literal>WHERE</literal> clause can refer
only to columns of the underlying table, but it can use all columns,
not just the ones being indexed. Presently, subqueries and
aggregate expressions are also forbidden in <literal>WHERE</literal>.
@@ -172,7 +172,7 @@ CREATE [ UNIQUE ] INDEX [ CONCURRENTLY ] <replaceable class="parameter">name</re
<para>
An expression based on one or more columns of the table. The
expression usually must be written with surrounding parentheses,
as shown in the syntax. However, the parentheses may be omitted
as shown in the syntax. However, the parentheses can be omitted
if the expression has the form of a function call.
</para>
</listitem>
@@ -324,14 +324,14 @@ CREATE [ UNIQUE ] INDEX [ CONCURRENTLY ] <replaceable class="parameter">name</re
significantly longer to complete. However, since it allows normal
operations to continue while the index is built, this method is useful for
adding new indexes in a production environment. Of course, the extra CPU
and I/O load imposed by the index creation may slow other operations.
and I/O load imposed by the index creation might slow other operations.
</para>
<para>
If a problem arises during the second scan of the table, such as a
uniqueness violation in a unique index, the <command>CREATE INDEX</>
command will fail but leave behind an <quote>invalid</> index. This index
will be ignored for querying purposes because it may be incomplete;
will be ignored for querying purposes because it might be incomplete;
however it will still consume update overhead. The recommended recovery
method in such cases is to drop the index and try again to perform
<command>CREATE INDEX CONCURRENTLY</>. (Another possibility is to rebuild
@@ -378,7 +378,7 @@ CREATE [ UNIQUE ] INDEX [ CONCURRENTLY ] <replaceable class="parameter">name</re
<para>
Currently, only the B-tree and GiST index methods support
multicolumn indexes. Up to 32 fields may be specified by default.
multicolumn indexes. Up to 32 fields can be specified by default.
(This limit can be altered when building
<productname>PostgreSQL</productname>.) Only B-tree currently
supports unique indexes.