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SQL commands are generally marked up as <command>, except when a link to a reference page is used using <xref>. But the latter doesn't create monospace markup, so this looks strange especially when a paragraph contains a mix of links and non-links. We considered putting <command> in the <refentrytitle> on the target side, but that creates some formatting side effects elsewhere. Generally, it seems safer to solve this on the link source side. We can't put the <xref> inside the <command>; the DTD doesn't allow this. DocBook 5 would allow the <command> to have the linkend attribute itself, but we are not there yet. So to solve this for now, convert the <xref>s to <link> plus <command>. This gives the correct look and also gives some more flexibility what we can put into the link text (e.g., subcommands or other clauses). In the future, these could then be converted to DocBook 5 style. I haven't converted absolutely all xrefs to SQL command reference pages, only those where we care about the appearance of the link text or where it was otherwise appropriate to make the appearance match a bit better. Also in some cases, the links where repetitive, so in those cases the links where just removed and replaced by a plain <command>. In cases where we just want the link and don't specifically care about the generated link text (typically phrased "for further information see <xref ...>") the xref is kept. Reported-by: Dagfinn Ilmari Mannsåker <ilmari@ilmari.org> Discussion: https://www.postgresql.org/message-id/flat/87o8pco34z.fsf@wibble.ilmari.org
98 lines
3.0 KiB
Plaintext
98 lines
3.0 KiB
Plaintext
<!--
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doc/src/sgml/ref/start_transaction.sgml
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PostgreSQL documentation
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-->
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<refentry id="sql-start-transaction">
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<indexterm zone="sql-start-transaction">
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<primary>START TRANSACTION</primary>
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</indexterm>
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<refmeta>
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<refentrytitle>START TRANSACTION</refentrytitle>
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<manvolnum>7</manvolnum>
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<refmiscinfo>SQL - Language Statements</refmiscinfo>
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</refmeta>
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<refnamediv>
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<refname>START TRANSACTION</refname>
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<refpurpose>start a transaction block</refpurpose>
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</refnamediv>
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<refsynopsisdiv>
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<synopsis>
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START TRANSACTION [ <replaceable class="parameter">transaction_mode</replaceable> [, ...] ]
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<phrase>where <replaceable class="parameter">transaction_mode</replaceable> is one of:</phrase>
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ISOLATION LEVEL { SERIALIZABLE | REPEATABLE READ | READ COMMITTED | READ UNCOMMITTED }
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READ WRITE | READ ONLY
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[ NOT ] DEFERRABLE
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</synopsis>
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</refsynopsisdiv>
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<refsect1>
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<title>Description</title>
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<para>
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This command begins a new transaction block. If the isolation level,
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read/write mode, or deferrable mode is specified, the new transaction has those
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characteristics, as if <link linkend="sql-set-transaction"><command>SET TRANSACTION</command></link> was executed. This is the same
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as the <link linkend="sql-begin"><command>BEGIN</command></link> command.
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</para>
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</refsect1>
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<refsect1>
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<title>Parameters</title>
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<para>
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Refer to <xref linkend="sql-set-transaction"/> for information on the meaning
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of the parameters to this statement.
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</para>
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</refsect1>
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<refsect1>
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<title>Compatibility</title>
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<para>
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In the standard, it is not necessary to issue <command>START TRANSACTION</command>
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to start a transaction block: any SQL command implicitly begins a block.
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<productname>PostgreSQL</productname>'s behavior can be seen as implicitly
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issuing a <command>COMMIT</command> after each command that does not
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follow <command>START TRANSACTION</command> (or <command>BEGIN</command>),
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and it is therefore often called <quote>autocommit</quote>.
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Other relational database systems might offer an autocommit feature
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as a convenience.
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</para>
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<para>
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The <literal>DEFERRABLE</literal>
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<replaceable class="parameter">transaction_mode</replaceable>
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is a <productname>PostgreSQL</productname> language extension.
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</para>
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<para>
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The SQL standard requires commas between successive <replaceable
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class="parameter">transaction_modes</replaceable>, but for historical
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reasons <productname>PostgreSQL</productname> allows the commas to be
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omitted.
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</para>
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<para>
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See also the compatibility section of <xref linkend="sql-set-transaction"/>.
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</para>
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</refsect1>
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<refsect1>
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<title>See Also</title>
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<simplelist type="inline">
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<member><xref linkend="sql-begin"/></member>
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<member><xref linkend="sql-commit"/></member>
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<member><xref linkend="sql-rollback"/></member>
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<member><xref linkend="sql-savepoint"/></member>
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<member><xref linkend="sql-set-transaction"/></member>
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</simplelist>
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</refsect1>
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</refentry>
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