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Don't use SGML empty tags

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For DocBook XML compatibility, don't use SGML empty tags (</>) anymore,
replace by the full tag name.  Add a warning option to catch future
occurrences.

Alexander Lakhin, Jürgen Purtz
This commit is contained in:
Peter Eisentraut
2017-10-08 21:44:17 -04:00
parent 6ecabead4b
commit c29c578908
337 changed files with 31636 additions and 31635 deletions
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56
doc/src/sgml/ref/declare.sgml
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@@ -45,7 +45,7 @@ DECLARE <replaceable class="parameter">name</replaceable> [ BINARY ] [ INSENSITI
<note>
<para>
This page describes usage of cursors at the SQL command level.
If you are trying to use cursors inside a <application>PL/pgSQL</>
If you are trying to use cursors inside a <application>PL/pgSQL</application>
function, the rules are different &mdash;
see <xref linkend="plpgsql-cursors">.
</para>
@@ -144,13 +144,13 @@ DECLARE <replaceable class="parameter">name</replaceable> [ BINARY ] [ INSENSITI
<para>
Normal cursors return data in text format, the same as a
<command>SELECT</> would produce. The <literal>BINARY</> option
<command>SELECT</command> would produce. The <literal>BINARY</literal> option
specifies that the cursor should return data in binary format.
This reduces conversion effort for both the server and client,
at the cost of more programmer effort to deal with platform-dependent
binary data formats.
As an example, if a query returns a value of one from an integer column,
you would get a string of <literal>1</> with a default cursor,
you would get a string of <literal>1</literal> with a default cursor,
whereas with a binary cursor you would get
a 4-byte field containing the internal representation of the value
(in big-endian byte order).
@@ -165,8 +165,8 @@ DECLARE <replaceable class="parameter">name</replaceable> [ BINARY ] [ INSENSITI
<note>
<para>
When the client application uses the <quote>extended query</> protocol
to issue a <command>FETCH</> command, the Bind protocol message
When the client application uses the <quote>extended query</quote> protocol
to issue a <command>FETCH</command> command, the Bind protocol message
specifies whether data is to be retrieved in text or binary format.
This choice overrides the way that the cursor is defined. The concept
of a binary cursor as such is thus obsolete when using extended query
@@ -177,7 +177,7 @@ DECLARE <replaceable class="parameter">name</replaceable> [ BINARY ] [ INSENSITI
<para>
Unless <literal>WITH HOLD</literal> is specified, the cursor
created by this command can only be used within the current
transaction. Thus, <command>DECLARE</> without <literal>WITH
transaction. Thus, <command>DECLARE</command> without <literal>WITH
HOLD</literal> is useless outside a transaction block: the cursor would
survive only to the completion of the statement. Therefore
<productname>PostgreSQL</productname> reports an error if such a
@@ -204,25 +204,25 @@ DECLARE <replaceable class="parameter">name</replaceable> [ BINARY ] [ INSENSITI
<para>
<literal>WITH HOLD</literal> may not be specified when the query
includes <literal>FOR UPDATE</> or <literal>FOR SHARE</>.
includes <literal>FOR UPDATE</literal> or <literal>FOR SHARE</literal>.
</para>
<para>
The <literal>SCROLL</> option should be specified when defining a
The <literal>SCROLL</literal> option should be specified when defining a
cursor that will be used to fetch backwards. This is required by
the SQL standard. However, for compatibility with earlier
versions, <productname>PostgreSQL</productname> will allow
backward fetches without <literal>SCROLL</>, if the cursor's query
backward fetches without <literal>SCROLL</literal>, if the cursor's query
plan is simple enough that no extra overhead is needed to support
it. However, application developers are advised not to rely on
using backward fetches from a cursor that has not been created
with <literal>SCROLL</literal>. If <literal>NO SCROLL</> is
with <literal>SCROLL</literal>. If <literal>NO SCROLL</literal> is
specified, then backward fetches are disallowed in any case.
</para>
<para>
Backward fetches are also disallowed when the query
includes <literal>FOR UPDATE</> or <literal>FOR SHARE</>; therefore
includes <literal>FOR UPDATE</literal> or <literal>FOR SHARE</literal>; therefore
<literal>SCROLL</literal> may not be specified in this case.
</para>
@@ -241,42 +241,42 @@ DECLARE <replaceable class="parameter">name</replaceable> [ BINARY ] [ INSENSITI
</caution>
<para>
If the cursor's query includes <literal>FOR UPDATE</> or <literal>FOR
SHARE</>, then returned rows are locked at the time they are first
If the cursor's query includes <literal>FOR UPDATE</literal> or <literal>FOR
SHARE</literal>, then returned rows are locked at the time they are first
fetched, in the same way as for a regular
<xref linkend="sql-select"> command with
these options.
In addition, the returned rows will be the most up-to-date versions;
therefore these options provide the equivalent of what the SQL standard
calls a <quote>sensitive cursor</>. (Specifying <literal>INSENSITIVE</>
together with <literal>FOR UPDATE</> or <literal>FOR SHARE</> is an error.)
calls a <quote>sensitive cursor</quote>. (Specifying <literal>INSENSITIVE</literal>
together with <literal>FOR UPDATE</literal> or <literal>FOR SHARE</literal> is an error.)
</para>
<caution>
<para>
It is generally recommended to use <literal>FOR UPDATE</> if the cursor
is intended to be used with <command>UPDATE ... WHERE CURRENT OF</> or
<command>DELETE ... WHERE CURRENT OF</>. Using <literal>FOR UPDATE</>
It is generally recommended to use <literal>FOR UPDATE</literal> if the cursor
is intended to be used with <command>UPDATE ... WHERE CURRENT OF</command> or
<command>DELETE ... WHERE CURRENT OF</command>. Using <literal>FOR UPDATE</literal>
prevents other sessions from changing the rows between the time they are
fetched and the time they are updated. Without <literal>FOR UPDATE</>,
a subsequent <literal>WHERE CURRENT OF</> command will have no effect if
fetched and the time they are updated. Without <literal>FOR UPDATE</literal>,
a subsequent <literal>WHERE CURRENT OF</literal> command will have no effect if
the row was changed since the cursor was created.
</para>
<para>
Another reason to use <literal>FOR UPDATE</> is that without it, a
subsequent <literal>WHERE CURRENT OF</> might fail if the cursor query
Another reason to use <literal>FOR UPDATE</literal> is that without it, a
subsequent <literal>WHERE CURRENT OF</literal> might fail if the cursor query
does not meet the SQL standard's rules for being <quote>simply
updatable</> (in particular, the cursor must reference just one table
and not use grouping or <literal>ORDER BY</>). Cursors
updatable</quote> (in particular, the cursor must reference just one table
and not use grouping or <literal>ORDER BY</literal>). Cursors
that are not simply updatable might work, or might not, depending on plan
choice details; so in the worst case, an application might work in testing
and then fail in production.
</para>
<para>
The main reason not to use <literal>FOR UPDATE</> with <literal>WHERE
CURRENT OF</> is if you need the cursor to be scrollable, or to be
The main reason not to use <literal>FOR UPDATE</literal> with <literal>WHERE
CURRENT OF</literal> is if you need the cursor to be scrollable, or to be
insensitive to the subsequent updates (that is, continue to show the old
data). If this is a requirement, pay close heed to the caveats shown
above.
@@ -321,13 +321,13 @@ DECLARE liahona CURSOR FOR SELECT * FROM films;
The SQL standard says that it is implementation-dependent whether cursors
are sensitive to concurrent updates of the underlying data by default. In
<productname>PostgreSQL</productname>, cursors are insensitive by default,
and can be made sensitive by specifying <literal>FOR UPDATE</>. Other
and can be made sensitive by specifying <literal>FOR UPDATE</literal>. Other
products may work differently.
</para>
<para>
The SQL standard allows cursors only in embedded
<acronym>SQL</acronym> and in modules. <productname>PostgreSQL</>
<acronym>SQL</acronym> and in modules. <productname>PostgreSQL</productname>
permits cursors to be used interactively.
</para>