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Fix wording on allowed/forbidden keyword usage.

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Thanks to Michael Deck <deckm@cleansoft.com> for the tipoff.
Add more examples for language components.
This commit is contained in:
Thomas G. Lockhart 1999-09-01 02:37:40 +00:00
parent e25e6a6dc3
commit db5d724986
1 changed files with 40 additions and 8 deletions
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48
doc/src/sgml/syntax.sgml
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@ -207,7 +207,7 @@ WHENEVER WRITE
<para>
<acronym>SQL92</acronym> and <acronym>SQL3</acronym> have
<firstterm>non-reserved keywords</firstterm> which have
a proscribed meaning in the language but which are also allowed
a prescribed meaning in the language but which are also allowed
as identifiers.
<productname>Postgres</productname> has additional keywords
which allow similar unrestricted usage.
@ -324,7 +324,8 @@ We also support C-style block comments, e.g.:
<programlisting>
/* multi
line
comment */
comment
*/
</programlisting>
</para>
</sect1>
@ -336,8 +337,16 @@ We also support C-style block comments, e.g.:
Names in SQL are sequences of less than NAMEDATALEN alphanumeric characters,
starting with an alphabetic character. By default, NAMEDATALEN is set
to 32, but at the time the system is built, NAMEDATALEN can be changed
by changing the #ifdef in src/backend/include/postgres.h. Underscore
("_") is considered an alphabetic character.
by changing the <literal>#define</literal> in
src/backend/include/postgres.h.
Underscore ("_") is considered an alphabetic character.
</para>
<para>
In some contexts, names may contain other characters if surrounded
by double quotes. For example, table or column names may contain otherwise
disallowed characters such as spaces, ampersands, etc. using this
technique.
</para>
</sect1>
@ -356,7 +365,7 @@ We also support C-style block comments, e.g.:
<para>
<firstterm>Strings</firstterm>
in SQL are arbitrary sequences of ASCII characters bounded by single
quotes ("'", e.g. 'This is a string').
quotes ("'", e.g. <literal>'This is a string'</literal>).
Uppercase alphabetics within strings are accepted
literally. Non-printing characters may be embedded within strings by
prepending them with a backslash
@ -385,6 +394,17 @@ We also support C-style block comments, e.g.:
values range from -2147483648 to +2147483647. This will vary
depending on the operating system and host machine.
</para>
<para>
Note that larger integers can be specified for <type>int8</type>
by using <acronym>SQL92</acronym> string notation or
<productname>Postgres</productname> type notation:
<programlisting>
int8 '4000000000' -- string style
'4000000000'::int8 -- Postgres (historical) style
</programlisting>
</para>
</sect2>
<sect2>
@ -403,8 +423,19 @@ We also support C-style block comments, e.g.:
You must include at least one <replaceable>dig</replaceable> after the
period and after the [+-] if you use those options. An exponent with
a missing mantissa has a mantissa of 1 inserted. There may be no
extra characters embedded in the string.
Floating point constaints are of type float8.
extra characters embedded in the string.
</para>
<para>
Floating point constaints are of type
<type>float8</type>. <type>float4</type> can be specified
explicitly by using <acronym>SQL92</acronym> string notation or
<productname>Postgres</productname> type notation:
<programlisting>
float4 '1.23' -- string style
'1.23'::float4 -- Postgres (historical) style
</programlisting>
</para>
</sect2>
@ -423,7 +454,8 @@ CAST '<replaceable>string</replaceable>' AS <replaceable>type</replaceable>
</synopsis>
The value inside the string is passed to the input
conversion routine for the type called type-name. The result is a
conversion routine for the type called
<replaceable>type</replaceable>. The result is a
constant of the indicated type. The explicit typecast may be omitted
if there is no ambiguity as to the type the constant must be, in which
case it is automatically coerced.