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authorDavid Rowley <drowley@postgresql.org>2024-01-30 10:15:51 +1300
committerDavid Rowley <drowley@postgresql.org>2024-01-30 10:15:51 +1300
commit1c8336e3e2f35e3968f73afc3a78ff34aaa523e2 (patch)
tree2456ec743a83ea609faea4f49bac8f683c128db5 /doc/src/sgml/ref/create_table.sgml
parent1b924a86e696c25775e873ccd4cac1f24ec6502f (diff)
Doc: mention foreign keys can reference unique indexes
We seem to have only documented a foreign key can reference the columns of a primary key or unique constraint. Here we adjust the documentation to mention columns in a non-partial unique index can be mentioned too. The header comment for transformFkeyCheckAttrs() also didn't mention unique indexes, so fix that too. In passing make that header comment reflect reality in the various other aspects where it deviated from it. Bug: 18295 Reported-by: Gilles PARC Author: Laurenz Albe, David Rowley Discussion: https://www.postgresql.org/message-id/18295-0ed0fac5c9f7b17b%40postgresql.org Backpatch-through: 12
Diffstat (limited to 'doc/src/sgml/ref/create_table.sgml')
-rw-r--r--doc/src/sgml/ref/create_table.sgml19
1 files changed, 13 insertions, 6 deletions
diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml
index 10ef699fab9..6a15676d882 100644
--- a/doc/src/sgml/ref/create_table.sgml
+++ b/doc/src/sgml/ref/create_table.sgml
@@ -1137,10 +1137,11 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
column(s) of some row of the referenced table. If the <replaceable
class="parameter">refcolumn</replaceable> list is omitted, the
primary key of the <replaceable class="parameter">reftable</replaceable>
- is used. The referenced columns must be the columns of a non-deferrable
- unique or primary key constraint in the referenced table. The user
- must have <literal>REFERENCES</literal> permission on the referenced table
- (either the whole table, or the specific referenced columns). The
+ is used. Otherwise, the <replaceable class="parameter">refcolumn</replaceable>
+ list must refer to the columns of a non-deferrable unique or primary key
+ constraint or be the columns of a non-partial unique index. The user
+ must have <literal>REFERENCES</literal> permission on the referenced
+ table (either the whole table, or the specific referenced columns). The
addition of a foreign key constraint requires a
<literal>SHARE ROW EXCLUSIVE</literal> lock on the referenced table.
Note that foreign key constraints cannot be defined between temporary
@@ -2277,13 +2278,19 @@ CREATE TABLE cities_partdef
</refsect2>
<refsect2>
- <title>Foreign-Key Constraint Actions</title>
+ <title>Foreign Key Constraints</title>
<para>
- The ability to specify column lists in the foreign-key actions
+ The ability to specify column lists in the foreign key actions
<literal>SET DEFAULT</literal> and <literal>SET NULL</literal> is a
<productname>PostgreSQL</productname> extension.
</para>
+
+ <para>
+ It is a <productname>PostgreSQL</productname> extension that a
+ foreign key constraint may reference columns of a unique index instead of
+ columns of a primary key or unique constraint.
+ </para>
</refsect2>
<refsect2>