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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
130 lines
3.3 KiB
Plaintext
130 lines
3.3 KiB
Plaintext
<!--
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doc/src/sgml/ref/drop_table.sgml
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PostgreSQL documentation
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-->
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<refentry id="sql-droptable">
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<indexterm zone="sql-droptable">
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<primary>DROP TABLE</primary>
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</indexterm>
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<refmeta>
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<refentrytitle>DROP TABLE</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>DROP TABLE</refname>
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<refpurpose>remove a table</refpurpose>
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</refnamediv>
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<refsynopsisdiv>
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<synopsis>
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DROP TABLE [ IF EXISTS ] <replaceable class="parameter">name</replaceable> [, ...] [ CASCADE | RESTRICT ]
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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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<command>DROP TABLE</command> removes tables from the database.
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Only the table owner, the schema owner, and superuser can drop a
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table. To empty a table of rows
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without destroying the table, use <link linkend="sql-delete"><command>DELETE</command></link>
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or <link linkend="sql-truncate"><command>TRUNCATE</command></link>.
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</para>
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<para>
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<command>DROP TABLE</command> always removes any indexes, rules,
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triggers, and constraints that exist for the target table.
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However, to drop a table that is referenced by a view or a foreign-key
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constraint of another table, <literal>CASCADE</literal> must be
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specified. (<literal>CASCADE</literal> will remove a dependent view entirely,
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but in the foreign-key case it will only remove the foreign-key
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constraint, not the other table entirely.)
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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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<variablelist>
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<varlistentry>
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<term><literal>IF EXISTS</literal></term>
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<listitem>
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<para>
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Do not throw an error if the table does not exist. A notice is issued
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in this case.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><replaceable class="parameter">name</replaceable></term>
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<listitem>
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<para>
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The name (optionally schema-qualified) of the table to drop.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><literal>CASCADE</literal></term>
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<listitem>
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<para>
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Automatically drop objects that depend on the table (such as
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views),
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and in turn all objects that depend on those objects
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(see <xref linkend="ddl-depend"/>).
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><literal>RESTRICT</literal></term>
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<listitem>
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<para>
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Refuse to drop the table if any objects depend on it. This is
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the default.
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</para>
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</listitem>
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</varlistentry>
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</variablelist>
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</refsect1>
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<refsect1>
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<title>Examples</title>
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<para>
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To destroy two tables, <literal>films</literal> and
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<literal>distributors</literal>:
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<programlisting>
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DROP TABLE films, distributors;
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</programlisting></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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This command conforms to the SQL standard, except that the standard only
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allows one table to be dropped per command, and apart from the
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<literal>IF EXISTS</literal> option, which is a <productname>PostgreSQL</productname>
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extension.
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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-altertable"/></member>
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<member><xref linkend="sql-createtable"/></member>
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</simplelist>
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</refsect1>
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</refentry>
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