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Random copy-editing.

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This commit is contained in:
Peter Eisentraut
2003-11-04 09:55:39 +00:00
parent c119c554ed
commit 1d27de4cf4
21 changed files with 571 additions and 588 deletions
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98
doc/src/sgml/syntax.sgml
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@@ -1,5 +1,5 @@
<!--
$Header: /cvsroot/pgsql/doc/src/sgml/syntax.sgml,v 1.85 2003/11/01 01:56:29 petere Exp $
$Header: /cvsroot/pgsql/doc/src/sgml/syntax.sgml,v 1.86 2003/11/04 09:55:39 petere Exp $
-->
<chapter id="sql-syntax">
@@ -196,20 +196,16 @@ UPDATE "my_table" SET "a" = 5;
unquoted names are always folded to lower case. For example, the
identifiers <literal>FOO</literal>, <literal>foo</literal>, and
<literal>"foo"</literal> are considered the same by
<productname>PostgreSQL</productname>, but <literal>"Foo"</literal>
and <literal>"FOO"</literal> are different from these three and
each other.
<footnote>
<para>
The folding of unquoted names to lower case in <productname>PostgreSQL</>
is incompatible with the SQL standard, which says that unquoted
names should be folded to upper case. Thus, <literal>foo</literal>
should be equivalent to <literal>"FOO"</literal> not
<literal>"foo"</literal> according to the standard. If you want to
write portable applications you are advised to always quote a particular
name or never quote it.
</para>
</footnote>
<productname>PostgreSQL</productname>, but
<literal>"Foo"</literal> and <literal>"FOO"</literal> are
different from these three and each other. (The folding of
unquoted names to lower case in <productname>PostgreSQL</> is
incompatible with the SQL standard, which says that unquoted names
should be folded to upper case. Thus, <literal>foo</literal>
should be equivalent to <literal>"FOO"</literal> not
<literal>"foo"</literal> according to the standard. If you want
to write portable applications you are advised to always quote a
particular name or never quote it.
</para>
</sect2>
@@ -260,10 +256,12 @@ UPDATE "my_table" SET "a" = 5;
form feed, <literal>\n</literal> is a newline,
<literal>\r</literal> is a carriage return, <literal>\t</literal>
is a tab, and <literal>\<replaceable>xxx</replaceable></literal>,
where <replaceable>xxx</replaceable> is an octal number, is the
character with the corresponding ASCII code. Any other character
following a backslash is taken literally. Thus, to include a
backslash in a string constant, type two backslashes.
where <replaceable>xxx</replaceable> is an octal number, is a
byte with the corresponding code. (It is your responsibility
that the byte sequences you create are valid characters in the
server character set encoding.) Any other character following a
backslash is taken literally. Thus, to include a backslash in a
string constant, type two backslashes.
</para>
<para>
@@ -440,44 +438,8 @@ CAST ( '<replaceable>string</replaceable>' AS <replaceable>type</replaceable> )
or <literal>CAST()</literal> to specify the type of an array constant.
</para>
</sect3>
<sect3>
<title>Array constants</title>
<indexterm>
<primary>array</primary>
<secondary>constant</secondary>
</indexterm>
<para>
The general format of an array constant is the following:
<synopsis>
'{ <replaceable>val1</replaceable> <replaceable>delim</replaceable> <replaceable>val2</replaceable> <replaceable>delim</replaceable> ... }'
</synopsis>
where <replaceable>delim</replaceable> is the delimiter character
for the type, as recorded in its <literal>pg_type</literal>
entry. (For all built-in types, this is the comma character
<quote><literal>,</literal></>.) Each <replaceable>val</replaceable> is either a constant
of the array element type, or a subarray. An example of an
array constant is
<programlisting>
'{{1,2,3},{4,5,6},{7,8,9}}'
</programlisting>
This constant is a two-dimensional, 3-by-3 array consisting of three
subarrays of integers. For more information see <xref linkend="arrays">.
</para>
<para>
(Array constants are actually only a special case of the generic
type constants discussed in the previous section. The constant
is initially treated as a string and passed to the array input
conversion routine. An explicit type specification might be
necessary.)
</para>
</sect3>
</sect2>
<sect2 id="sql-syntax-operators">
<title>Operators</title>
@@ -622,7 +584,7 @@ CAST ( '<replaceable>string</replaceable>' AS <replaceable>type</replaceable> )
A comment is an arbitrary sequence of characters beginning with
double dashes and extending to the end of the line, e.g.:
<programlisting>
-- This is a standard SQL92 comment
-- This is a standard SQL comment
</programlisting>
</para>
@@ -635,7 +597,7 @@ CAST ( '<replaceable>string</replaceable>' AS <replaceable>type</replaceable> )
</programlisting>
where the comment begins with <literal>/*</literal> and extends to
the matching occurrence of <literal>*/</literal>. These block
comments nest, as specified in SQL99 but unlike C, so that one can
comments nest, as specified in the SQL standard but unlike C, so that one can
comment out larger blocks of code that may contain existing block
comments.
</para>
@@ -1267,7 +1229,7 @@ CAST ( <replaceable>expression</replaceable> AS <replaceable>type</replaceable>
there is no error; the scalar result is taken to be null.)
The subquery can refer to variables from the surrounding query,
which will act as constants during any one evaluation of the subquery.
See also <xref linkend="functions-subquery">.
See also <xref linkend="functions-subquery"> for other expressions involving subqueries.
</para>
<para>
@@ -1289,7 +1251,7 @@ SELECT name, (SELECT max(pop) FROM cities WHERE cities.state = states.name)
</indexterm>
<para>
An <firstterm>array constructor</> is an expression that builds an
An array constructor is an expression that builds an
array value from values for its member elements. A simple array
constructor
consists of the key word <literal>ARRAY</literal>, a left square bracket
@@ -1337,11 +1299,11 @@ SELECT ARRAY[[1,2],[3,4]];
an array of the proper kind, not only a sub-<literal>ARRAY</> construct.
For example:
<programlisting>
create table arr(f1 int[], f2 int[]);
CREATE TABLE
insert into arr values (ARRAY[[1,2],[3,4]],ARRAY[[5,6],[7,8]]);
INSERT 2635544 1
select ARRAY[f1, f2, '{{9,10},{11,12}}'::int[]] from arr;
CREATE TABLE arr(f1 int[], f2 int[]);
INSERT INTO arr VALUES (ARRAY[[1,2],[3,4]], ARRAY[[5,6],[7,8]]);
SELECT ARRAY[f1, f2, '{{9,10},{11,12}}'::int[]] FROM arr;
array
------------------------------------------------
{{{1,2},{3,4}},{{5,6},{7,8}},{{9,10},{11,12}}}
@@ -1361,10 +1323,10 @@ SELECT ARRAY(SELECT oid FROM pg_proc WHERE proname LIKE 'bytea%');
{2011,1954,1948,1952,1951,1244,1950,2005,1949,1953,2006,31}
(1 row)
</programlisting>
The subquery must return a single column. The
resulting one-dimensional array will have an element for each row in the
subquery result, with an element type matching that of the subquery's
output column.
The subquery must return a single column. The resulting
one-dimensional array will have an element for each row in the
subquery result, with an element type matching that of the
subquery's output column.
</para>
<para>