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Commit4997878

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Doc: clarify that DROP ... CASCADE is recursive.
Apparently that's not obvious to everybody, so let's belabor the point.In passing, document that DROP POLICY has CASCADE/RESTRICT options (whichit does, per gram.y) but they do nothing (I assume, anyway). Also updatesome long-obsolete commentary in gram.y.Discussion: <20160805104837.1412.84915@wrigleys.postgresql.org>
1 parent4b234fd commit4997878

35 files changed

+144
-48
lines changed

‎doc/src/sgml/ddl.sgml‎

Lines changed: 17 additions & 6 deletions
Original file line numberDiff line numberDiff line change
@@ -2611,7 +2611,7 @@ VALUES ('Albany', NULL, NULL, 'NY');
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if they are inherited
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from any parent tables. If you wish to remove a table and all of its
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descendants, one easy way is to drop the parent table with the
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<literal>CASCADE</literal> option.
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<literal>CASCADE</literal> option (see <xref linkend="ddl-depend">).
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</para>
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<para>
@@ -3586,20 +3586,22 @@ HINT: Use DROP ... CASCADE to drop the dependent objects too.
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<screen>
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DROP TABLE products CASCADE;
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</screen>
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and all the dependent objects will be removed. In this case, it
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doesn't remove the orders table, it only removes the foreign key
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constraint. (If you want to check what <command>DROP ... CASCADE</> will do,
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and all the dependent objects will be removed, as will any objects
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that depend on them, recursively. In this case, it doesn't remove
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the orders table, it only removes the foreign key constraint.
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It stops there because nothing depends on the foreign key constraint.
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(If you want to check what <command>DROP ... CASCADE</> will do,
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run <command>DROP</> without <literal>CASCADE</> and read the
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<literal>DETAIL</> output.)
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</para>
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<para>
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All <command>DROP</> commands in <productname>PostgreSQL</> support
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Almost all <command>DROP</> commands in <productname>PostgreSQL</> support
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specifying <literal>CASCADE</literal>. Of course, the nature of
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the possible dependencies varies with the type of the object. You
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can also write <literal>RESTRICT</literal> instead of
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<literal>CASCADE</literal> to get the default behavior, which is to
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preventthedroppingofobjects that other objects depend on.
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prevent dropping objects that any other objects depend on.
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</para>
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<note>
@@ -3613,6 +3615,15 @@ DROP TABLE products CASCADE;
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</para>
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</note>
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<para>
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If a <command>DROP</> command lists multiple
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objects, <literal>CASCADE</literal> is only required when there are
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dependencies outside the specified group. For example, when saying
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<literal>DROP TABLE tab1, tab2</literal> the existence of a foreign
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key referencing <literal>tab1</> from <literal>tab2</> would not mean
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that <literal>CASCADE</literal> is needed to succeed.
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</para>
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<para>
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For user-defined functions, <productname>PostgreSQL</productname> tracks
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dependencies associated with a function's externally-visible properties,

‎doc/src/sgml/ref/alter_domain.sgml‎

Lines changed: 3 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -212,7 +212,9 @@ ALTER DOMAIN <replaceable class="PARAMETER">name</replaceable>
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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 constraint.
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Automatically drop objects that depend on the constraint,
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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>

‎doc/src/sgml/ref/alter_foreign_table.sgml‎

Lines changed: 3 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -431,7 +431,9 @@ ALTER FOREIGN TABLE [ IF EXISTS ] <replaceable class="PARAMETER">name</replaceab
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<listitem>
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<para>
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Automatically drop objects that depend on the dropped column
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or constraint (for example, views referencing the column).
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or constraint (for example, views referencing the column),
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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>

‎doc/src/sgml/ref/alter_table.sgml‎

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@@ -823,7 +823,9 @@ ALTER TABLE ALL IN TABLESPACE <replaceable class="PARAMETER">name</replaceable>
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<listitem>
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<para>
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Automatically drop objects that depend on the dropped column
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or constraint (for example, views referencing the column).
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or constraint (for example, views referencing the column),
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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>

‎doc/src/sgml/ref/drop_access_method.sgml‎

Lines changed: 3 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -62,7 +62,9 @@ DROP ACCESS METHOD [ IF EXISTS ] <replaceable class="parameter">name</replaceabl
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<listitem>
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<para>
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Automatically drop objects that depend on the access method
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(such as operator classes, operator families, indexes).
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(such as operator classes, operator families, and indexes),
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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>

‎doc/src/sgml/ref/drop_aggregate.sgml‎

Lines changed: 4 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -107,7 +107,10 @@ DROP AGGREGATE [ IF EXISTS ] <replaceable>name</replaceable> ( <replaceable>aggr
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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 aggregate function.
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Automatically drop objects that depend on the aggregate function
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(such as views using it),
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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>

‎doc/src/sgml/ref/drop_collation.sgml‎

Lines changed: 3 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -60,7 +60,9 @@ DROP COLLATION [ IF EXISTS ] <replaceable>name</replaceable> [ CASCADE | RESTRIC
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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 collation.
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Automatically drop objects that depend on the collation,
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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>

‎doc/src/sgml/ref/drop_domain.sgml‎

Lines changed: 3 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -62,7 +62,9 @@ DROP DOMAIN [ IF EXISTS ] <replaceable class="PARAMETER">name</replaceable> [, .
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<listitem>
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<para>
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Automatically drop objects that depend on the domain (such as
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table columns).
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table columns),
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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>

‎doc/src/sgml/ref/drop_event_trigger.sgml‎

Lines changed: 3 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -63,7 +63,9 @@ DROP EVENT TRIGGER [ IF EXISTS ] <replaceable class="PARAMETER">name</replaceabl
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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 trigger.
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Automatically drop objects that depend on the trigger,
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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>

‎doc/src/sgml/ref/drop_extension.sgml‎

Lines changed: 3 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -66,7 +66,9 @@ DROP EXTENSION [ IF EXISTS ] <replaceable class="PARAMETER">name</replaceable> [
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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 extension.
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Automatically drop objects that depend on the extension,
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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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