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A bunch of small doco updates motivated by scanning the comments on

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the interactive docs.
This commit is contained in:
Tom Lane
2001-11-19 03:58:25 +00:00
parent 9f07cb70db
commit 9b03776ff2
22 changed files with 256 additions and 154 deletions
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18
doc/src/sgml/array.sgml
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@@ -1,4 +1,4 @@
<!-- $Header: /cvsroot/pgsql/doc/src/sgml/array.sgml,v 1.13 2001/11/03 21:42:47 tgl Exp $ -->
<!-- $Header: /cvsroot/pgsql/doc/src/sgml/array.sgml,v 1.14 2001/11/19 03:58:23 tgl Exp $ -->
<chapter id="arrays">
<title>Arrays</title>
@@ -19,6 +19,8 @@ CREATE TABLE sal_emp (
schedule text[][]
);
</programlisting>
As shown, an array data type is named by appending square brackets
(<literal>[ ]</>) to the data type name of the array elements.
The above query will create a table named
<structname>sal_emp</structname> with a <type>text</type> string
(<structfield>name</structfield>), a one-dimensional array of type
@@ -31,7 +33,7 @@ CREATE TABLE sal_emp (
<para>
Now we do some <command>INSERT</command>s. Observe that to write an array
value, we enclose the element values within braces and separate them
value, we enclose the element values within curly braces and separate them
by commas. If you know C, this is not unlike the syntax for
initializing structures.
@@ -63,6 +65,7 @@ SELECT name FROM sal_emp WHERE pay_by_quarter[1] &lt;&gt; pay_by_quarter[2];
(1 row)
</programlisting>
The array subscript numbers are written within square brackets.
<productname>Postgres</productname> uses the
<quote>one-based</quote> numbering convention for arrays, that is,
an array of n elements starts with <literal>array[1]</literal> and
@@ -163,7 +166,7 @@ CREATE TABLE tictactoe (
<para>
Actually, the current implementation does not enforce the declared
number of dimensions either. Arrays of a particular base type are
number of dimensions either. Arrays of a particular element type are
all considered to be of the same type, regardless of size or number
of dimensions.
</para>
@@ -236,4 +239,13 @@ SELECT * FROM sal_emp WHERE pay_by_quarter **= 10000;
</para>
</tip>
<note>
<para>
A limitation of the present array implementation is that individual
elements of an array cannot be SQL NULLs. The entire array can be set
to NULL, but you can't have an array with some elements NULL and some
not. Fixing this is on the TODO list.
</para>
</note>
</chapter>