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Diffstat (limited to 'doc/src/sgml/syntax.sgml')
| -rw-r--r-- | doc/src/sgml/syntax.sgml | 98 |
1 files changed, 30 insertions, 68 deletions
diff --git a/doc/src/sgml/syntax.sgml b/doc/src/sgml/syntax.sgml index 0a31d1127c4..dc77f0abc65 100644 --- a/doc/src/sgml/syntax.sgml +++ b/doc/src/sgml/syntax.sgml @@ -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> |