diff --git a/contrib/file_fdw/input/file_fdw.source b/contrib/file_fdw/input/file_fdw.source
index b608372825eb318081cb0161781303463174c36d..e975bc552e35fb8bbfeb1f24b4cc8429f46eef75 100644
--- a/contrib/file_fdw/input/file_fdw.source
+++ b/contrib/file_fdw/input/file_fdw.source
@@ -62,7 +62,7 @@ CREATE FOREIGN TABLE tbl () SERVER file_server OPTIONS (format 'csv', null '
CREATE FOREIGN TABLE tbl () SERVER file_server; -- ERROR
CREATE FOREIGN TABLE agg_text (
- a int2,
+ a int2 CHECK (a >= 0),
b float4
) SERVER file_server
OPTIONS (format 'text', filename '@abs_srcdir@/data/agg.data', delimiter ' ', null '\N');
@@ -72,11 +72,13 @@ CREATE FOREIGN TABLE agg_csv (
b float4
) SERVER file_server
OPTIONS (format 'csv', filename '@abs_srcdir@/data/agg.csv', header 'true', delimiter ';', quote '@', escape '"', null '');
+ALTER FOREIGN TABLE agg_csv ADD CHECK (a >= 0);
CREATE FOREIGN TABLE agg_bad (
a int2,
b float4
) SERVER file_server
OPTIONS (format 'csv', filename '@abs_srcdir@/data/agg.bad', header 'true', delimiter ';', quote '@', escape '"', null '');
+ALTER FOREIGN TABLE agg_bad ADD CHECK (a >= 0);
-- per-column options tests
CREATE FOREIGN TABLE text_csv (
@@ -134,6 +136,18 @@ DELETE FROM agg_csv WHERE a = 100;
-- but this should be ignored
SELECT * FROM agg_csv FOR UPDATE;
+-- constraint exclusion tests
+\t on
+EXPLAIN (VERBOSE, COSTS FALSE) SELECT * FROM agg_csv WHERE a < 0;
+\t off
+SELECT * FROM agg_csv WHERE a < 0;
+SET constraint_exclusion = 'on';
+\t on
+EXPLAIN (VERBOSE, COSTS FALSE) SELECT * FROM agg_csv WHERE a < 0;
+\t off
+SELECT * FROM agg_csv WHERE a < 0;
+RESET constraint_exclusion;
+
-- privilege tests
SET ROLE file_fdw_superuser;
SELECT * FROM agg_text ORDER BY a;
diff --git a/contrib/file_fdw/output/file_fdw.source b/contrib/file_fdw/output/file_fdw.source
index bc183b88744d94340f83dd578e1b829aba5704aa..6808d5b2f8f7750c39435fa9f9ec3b9761415a86 100644
--- a/contrib/file_fdw/output/file_fdw.source
+++ b/contrib/file_fdw/output/file_fdw.source
@@ -78,7 +78,7 @@ ERROR: COPY null representation cannot use newline or carriage return
CREATE FOREIGN TABLE tbl () SERVER file_server; -- ERROR
ERROR: filename is required for file_fdw foreign tables
CREATE FOREIGN TABLE agg_text (
- a int2,
+ a int2 CHECK (a >= 0),
b float4
) SERVER file_server
OPTIONS (format 'text', filename '@abs_srcdir@/data/agg.data', delimiter ' ', null '\N');
@@ -88,11 +88,13 @@ CREATE FOREIGN TABLE agg_csv (
b float4
) SERVER file_server
OPTIONS (format 'csv', filename '@abs_srcdir@/data/agg.csv', header 'true', delimiter ';', quote '@', escape '"', null '');
+ALTER FOREIGN TABLE agg_csv ADD CHECK (a >= 0);
CREATE FOREIGN TABLE agg_bad (
a int2,
b float4
) SERVER file_server
OPTIONS (format 'csv', filename '@abs_srcdir@/data/agg.bad', header 'true', delimiter ';', quote '@', escape '"', null '');
+ALTER FOREIGN TABLE agg_bad ADD CHECK (a >= 0);
-- per-column options tests
CREATE FOREIGN TABLE text_csv (
word1 text OPTIONS (force_not_null 'true'),
@@ -219,6 +221,34 @@ SELECT * FROM agg_csv FOR UPDATE;
42 | 324.78
(3 rows)
+-- constraint exclusion tests
+\t on
+EXPLAIN (VERBOSE, COSTS FALSE) SELECT * FROM agg_csv WHERE a < 0;
+ Foreign Scan on public.agg_csv
+ Output: a, b
+ Filter: (agg_csv.a < 0)
+ Foreign File: @abs_srcdir@/data/agg.csv
+
+\t off
+SELECT * FROM agg_csv WHERE a < 0;
+ a | b
+---+---
+(0 rows)
+
+SET constraint_exclusion = 'on';
+\t on
+EXPLAIN (VERBOSE, COSTS FALSE) SELECT * FROM agg_csv WHERE a < 0;
+ Result
+ Output: a, b
+ One-Time Filter: false
+
+\t off
+SELECT * FROM agg_csv WHERE a < 0;
+ a | b
+---+---
+(0 rows)
+
+RESET constraint_exclusion;
-- privilege tests
SET ROLE file_fdw_superuser;
SELECT * FROM agg_text ORDER BY a;
diff --git a/contrib/postgres_fdw/expected/postgres_fdw.out b/contrib/postgres_fdw/expected/postgres_fdw.out
index a335e56a9dfc6a68f34d9d6d8eab8f2cf91867db..583cce738aaa987bef3bbf6d7ad8b50663741ea3 100644
--- a/contrib/postgres_fdw/expected/postgres_fdw.out
+++ b/contrib/postgres_fdw/expected/postgres_fdw.out
@@ -2588,6 +2588,91 @@ select c2, count(*) from "S 1"."T 1" where c2 < 500 group by 1 order by 1;
407 | 100
(13 rows)
+-- ===================================================================
+-- test check constraints
+-- ===================================================================
+-- Consistent check constraints provide consistent results
+ALTER FOREIGN TABLE ft1 ADD CONSTRAINT ft1_c2positive CHECK (c2 >= 0);
+EXPLAIN (VERBOSE, COSTS false) SELECT count(*) FROM ft1 WHERE c2 < 0;
+ QUERY PLAN
+-------------------------------------------------------------------
+ Aggregate
+ Output: count(*)
+ -> Foreign Scan on public.ft1
+ Remote SQL: SELECT NULL FROM "S 1"."T 1" WHERE ((c2 < 0))
+(4 rows)
+
+SELECT count(*) FROM ft1 WHERE c2 < 0;
+ count
+-------
+ 0
+(1 row)
+
+SET constraint_exclusion = 'on';
+EXPLAIN (VERBOSE, COSTS false) SELECT count(*) FROM ft1 WHERE c2 < 0;
+ QUERY PLAN
+--------------------------------
+ Aggregate
+ Output: count(*)
+ -> Result
+ One-Time Filter: false
+(4 rows)
+
+SELECT count(*) FROM ft1 WHERE c2 < 0;
+ count
+-------
+ 0
+(1 row)
+
+RESET constraint_exclusion;
+-- check constraint is enforced on the remote side, not locally
+INSERT INTO ft1(c1, c2) VALUES(1111, -2); -- c2positive
+ERROR: new row for relation "T 1" violates check constraint "c2positive"
+DETAIL: Failing row contains (1111, -2, null, null, null, null, ft1 , null).
+CONTEXT: Remote SQL command: INSERT INTO "S 1"."T 1"("C 1", c2, c3, c4, c5, c6, c7, c8) VALUES ($1, $2, $3, $4, $5, $6, $7, $8)
+UPDATE ft1 SET c2 = -c2 WHERE c1 = 1; -- c2positive
+ERROR: new row for relation "T 1" violates check constraint "c2positive"
+DETAIL: Failing row contains (1, -1, 00001_trig_update, 1970-01-02 08:00:00+00, 1970-01-02 00:00:00, 1, 1 , foo).
+CONTEXT: Remote SQL command: UPDATE "S 1"."T 1" SET c2 = $2 WHERE ctid = $1
+ALTER FOREIGN TABLE ft1 DROP CONSTRAINT ft1_c2positive;
+-- But inconsistent check constraints provide inconsistent results
+ALTER FOREIGN TABLE ft1 ADD CONSTRAINT ft1_c2negative CHECK (c2 < 0);
+EXPLAIN (VERBOSE, COSTS false) SELECT count(*) FROM ft1 WHERE c2 >= 0;
+ QUERY PLAN
+--------------------------------------------------------------------
+ Aggregate
+ Output: count(*)
+ -> Foreign Scan on public.ft1
+ Remote SQL: SELECT NULL FROM "S 1"."T 1" WHERE ((c2 >= 0))
+(4 rows)
+
+SELECT count(*) FROM ft1 WHERE c2 >= 0;
+ count
+-------
+ 821
+(1 row)
+
+SET constraint_exclusion = 'on';
+EXPLAIN (VERBOSE, COSTS false) SELECT count(*) FROM ft1 WHERE c2 >= 0;
+ QUERY PLAN
+--------------------------------
+ Aggregate
+ Output: count(*)
+ -> Result
+ One-Time Filter: false
+(4 rows)
+
+SELECT count(*) FROM ft1 WHERE c2 >= 0;
+ count
+-------
+ 0
+(1 row)
+
+RESET constraint_exclusion;
+-- local check constraint is not actually enforced
+INSERT INTO ft1(c1, c2) VALUES(1111, 2);
+UPDATE ft1 SET c2 = c2 + 1 WHERE c1 = 1;
+ALTER FOREIGN TABLE ft1 DROP CONSTRAINT ft1_c2negative;
-- ===================================================================
-- test serial columns (ie, sequence-based defaults)
-- ===================================================================
diff --git a/contrib/postgres_fdw/sql/postgres_fdw.sql b/contrib/postgres_fdw/sql/postgres_fdw.sql
index fcfb10d29ea697a6884696a378e9e8e89e8e61de..83e8fa7b045f93481a20f07055d1f6f6224cbdcb 100644
--- a/contrib/postgres_fdw/sql/postgres_fdw.sql
+++ b/contrib/postgres_fdw/sql/postgres_fdw.sql
@@ -405,6 +405,36 @@ commit;
select c2, count(*) from ft2 where c2 < 500 group by 1 order by 1;
select c2, count(*) from "S 1"."T 1" where c2 < 500 group by 1 order by 1;
+-- ===================================================================
+-- test check constraints
+-- ===================================================================
+
+-- Consistent check constraints provide consistent results
+ALTER FOREIGN TABLE ft1 ADD CONSTRAINT ft1_c2positive CHECK (c2 >= 0);
+EXPLAIN (VERBOSE, COSTS false) SELECT count(*) FROM ft1 WHERE c2 < 0;
+SELECT count(*) FROM ft1 WHERE c2 < 0;
+SET constraint_exclusion = 'on';
+EXPLAIN (VERBOSE, COSTS false) SELECT count(*) FROM ft1 WHERE c2 < 0;
+SELECT count(*) FROM ft1 WHERE c2 < 0;
+RESET constraint_exclusion;
+-- check constraint is enforced on the remote side, not locally
+INSERT INTO ft1(c1, c2) VALUES(1111, -2); -- c2positive
+UPDATE ft1 SET c2 = -c2 WHERE c1 = 1; -- c2positive
+ALTER FOREIGN TABLE ft1 DROP CONSTRAINT ft1_c2positive;
+
+-- But inconsistent check constraints provide inconsistent results
+ALTER FOREIGN TABLE ft1 ADD CONSTRAINT ft1_c2negative CHECK (c2 < 0);
+EXPLAIN (VERBOSE, COSTS false) SELECT count(*) FROM ft1 WHERE c2 >= 0;
+SELECT count(*) FROM ft1 WHERE c2 >= 0;
+SET constraint_exclusion = 'on';
+EXPLAIN (VERBOSE, COSTS false) SELECT count(*) FROM ft1 WHERE c2 >= 0;
+SELECT count(*) FROM ft1 WHERE c2 >= 0;
+RESET constraint_exclusion;
+-- local check constraint is not actually enforced
+INSERT INTO ft1(c1, c2) VALUES(1111, 2);
+UPDATE ft1 SET c2 = c2 + 1 WHERE c1 = 1;
+ALTER FOREIGN TABLE ft1 DROP CONSTRAINT ft1_c2negative;
+
-- ===================================================================
-- test serial columns (ie, sequence-based defaults)
-- ===================================================================
diff --git a/doc/src/sgml/ref/alter_foreign_table.sgml b/doc/src/sgml/ref/alter_foreign_table.sgml
index 9d9c439315f3912ca38a0e0aa30effe2458ec504..ff48ab888299ff258e49d0323a54f561993e2c9e 100644
--- a/doc/src/sgml/ref/alter_foreign_table.sgml
+++ b/doc/src/sgml/ref/alter_foreign_table.sgml
@@ -42,6 +42,8 @@ ALTER FOREIGN TABLE [ IF EXISTS ] <replaceable class="PARAMETER">name</replaceab
ALTER [ COLUMN ] <replaceable class="PARAMETER">column_name</replaceable> SET ( <replaceable class="PARAMETER">attribute_option</replaceable> = <replaceable class="PARAMETER">value</replaceable> [, ... ] )
ALTER [ COLUMN ] <replaceable class="PARAMETER">column_name</replaceable> RESET ( <replaceable class="PARAMETER">attribute_option</replaceable> [, ... ] )
ALTER [ COLUMN ] <replaceable class="PARAMETER">column_name</replaceable> OPTIONS ( [ ADD | SET | DROP ] <replaceable class="PARAMETER">option</replaceable> ['<replaceable class="PARAMETER">value</replaceable>'] [, ... ])
+ ADD <replaceable class="PARAMETER">table_constraint</replaceable>
+ DROP CONSTRAINT [ IF EXISTS ] <replaceable class="PARAMETER">constraint_name</replaceable> [ RESTRICT | CASCADE ]
DISABLE TRIGGER [ <replaceable class="PARAMETER">trigger_name</replaceable> | ALL | USER ]
ENABLE TRIGGER [ <replaceable class="PARAMETER">trigger_name</replaceable> | ALL | USER ]
ENABLE REPLICA TRIGGER <replaceable class="PARAMETER">trigger_name</replaceable>
@@ -87,16 +89,6 @@ ALTER FOREIGN TABLE [ IF EXISTS ] <replaceable class="PARAMETER">name</replaceab
</listitem>
</varlistentry>
- <varlistentry>
- <term><literal>IF EXISTS</literal></term>
- <listitem>
- <para>
- Do not throw an error if the foreign table does not exist. A notice is
- issued in this case.
- </para>
- </listitem>
- </varlistentry>
-
<varlistentry>
<term><literal>SET DATA TYPE</literal></term>
<listitem>
@@ -153,41 +145,54 @@ ALTER FOREIGN TABLE [ IF EXISTS ] <replaceable class="PARAMETER">name</replaceab
</varlistentry>
<varlistentry>
- <term><literal>DISABLE</literal>/<literal>ENABLE [ REPLICA | ALWAYS ] TRIGGER</literal></term>
+ <term><literal>ADD <replaceable class="PARAMETER">table_constraint</replaceable></literal></term>
<listitem>
<para>
- These forms configure the firing of trigger(s) belonging to the foreign
- table. See the similar form of <xref linkend="sql-altertable"> for more
- details.
+ This form adds a new constraint to a foreign table, using the same
+ syntax as <xref linkend="SQL-CREATEFOREIGNTABLE">.
+ Currently only <literal>CHECK</> constraints are supported.
+ </para>
+
+ <para>
+ Unlike the case when adding a constraint to a regular table, nothing is
+ done to verify the constraint is correct; rather, this action simply
+ declares that some new condition holds for all rows in the foreign
+ table. (See the discussion in <xref linkend="SQL-CREATEFOREIGNTABLE">.)
+ Note that constraints on foreign tables cannot be marked
+ <literal>NOT VALID</> since such constraints are simply declarative.
</para>
</listitem>
</varlistentry>
<varlistentry>
- <term><literal>OWNER</literal></term>
+ <term><literal>DROP CONSTRAINT [ IF EXISTS ]</literal></term>
<listitem>
<para>
- This form changes the owner of the foreign table to the
- specified user.
+ This form drops the specified constraint on a foreign table.
+ If <literal>IF EXISTS</literal> is specified and the constraint
+ does not exist, no error is thrown.
+ In this case a notice is issued instead.
</para>
</listitem>
</varlistentry>
<varlistentry>
- <term><literal>RENAME</literal></term>
+ <term><literal>DISABLE</literal>/<literal>ENABLE [ REPLICA | ALWAYS ] TRIGGER</literal></term>
<listitem>
<para>
- The <literal>RENAME</literal> forms change the name of a foreign table
- or the name of an individual column in a foreign table.
+ These forms configure the firing of trigger(s) belonging to the foreign
+ table. See the similar form of <xref linkend="sql-altertable"> for more
+ details.
</para>
</listitem>
</varlistentry>
<varlistentry>
- <term><literal>SET SCHEMA</literal></term>
+ <term><literal>OWNER</literal></term>
<listitem>
<para>
- This form moves the foreign table into another schema.
+ This form changes the owner of the foreign table to the
+ specified user.
</para>
</listitem>
</varlistentry>
@@ -207,6 +212,25 @@ ALTER FOREIGN TABLE [ IF EXISTS ] <replaceable class="PARAMETER">name</replaceab
</listitem>
</varlistentry>
+ <varlistentry>
+ <term><literal>RENAME</literal></term>
+ <listitem>
+ <para>
+ The <literal>RENAME</literal> forms change the name of a foreign table
+ or the name of an individual column in a foreign table.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><literal>SET SCHEMA</literal></term>
+ <listitem>
+ <para>
+ This form moves the foreign table into another schema.
+ </para>
+ </listitem>
+ </varlistentry>
+
</variablelist>
</para>
@@ -218,6 +242,12 @@ ALTER FOREIGN TABLE [ IF EXISTS ] <replaceable class="PARAMETER">name</replaceab
columns in a single command.
</para>
+ <para>
+ If the command is written as <literal>ALTER FOREIGN TABLE IF EXISTS ...</>
+ and the foreign table does not exist, no error is thrown. A notice is
+ issued in this case.
+ </para>
+
<para>
You must own the table to use <command>ALTER FOREIGN TABLE</>.
To change the schema of a foreign table, you must also have
@@ -284,12 +314,30 @@ ALTER FOREIGN TABLE [ IF EXISTS ] <replaceable class="PARAMETER">name</replaceab
</listitem>
</varlistentry>
+ <varlistentry>
+ <term><replaceable class="PARAMETER">table_constraint</replaceable></term>
+ <listitem>
+ <para>
+ New table constraint for the foreign table.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><replaceable class="PARAMETER">constraint_name</replaceable></term>
+ <listitem>
+ <para>
+ Name of an existing constraint to drop.
+ </para>
+ </listitem>
+ </varlistentry>
+
<varlistentry>
<term><literal>CASCADE</literal></term>
<listitem>
<para>
Automatically drop objects that depend on the dropped column
- (for example, views referencing the column).
+ or constraint (for example, views referencing the column).
</para>
</listitem>
</varlistentry>
@@ -298,7 +346,7 @@ ALTER FOREIGN TABLE [ IF EXISTS ] <replaceable class="PARAMETER">name</replaceab
<term><literal>RESTRICT</literal></term>
<listitem>
<para>
- Refuse to drop the column if there are any dependent
+ Refuse to drop the column or constraint if there are any dependent
objects. This is the default behavior.
</para>
</listitem>
@@ -365,10 +413,10 @@ ALTER FOREIGN TABLE [ IF EXISTS ] <replaceable class="PARAMETER">name</replaceab
<para>
Consistency with the foreign server is not checked when a column is added
or removed with <literal>ADD COLUMN</literal> or
- <literal>DROP COLUMN</literal>, a <literal>NOT NULL</> constraint is
- added, or a column type is changed with <literal>SET DATA TYPE</>. It is
- the user's responsibility to ensure that the table definition matches the
- remote side.
+ <literal>DROP COLUMN</literal>, a <literal>NOT NULL</>
+ or <literal>CHECK</> constraint is added, or a column type is changed
+ with <literal>SET DATA TYPE</>. It is the user's responsibility to ensure
+ that the table definition matches the remote side.
</para>
<para>
@@ -413,4 +461,13 @@ ALTER FOREIGN TABLE myschema.distributors OPTIONS (ADD opt1 'value', SET opt2, '
extension of SQL, which disallows zero-column foreign tables.
</para>
</refsect1>
+
+ <refsect1>
+ <title>See Also</title>
+
+ <simplelist type="inline">
+ <member><xref linkend="sql-createforeigntable"></member>
+ <member><xref linkend="sql-dropforeigntable"></member>
+ </simplelist>
+ </refsect1>
</refentry>
diff --git a/doc/src/sgml/ref/create_foreign_table.sgml b/doc/src/sgml/ref/create_foreign_table.sgml
index 46a20eff14f8f25220a50fa23f1e311fe40f6a65..a24aa6e6d1dc7da0e8ff758c55e7cd5735217f76 100644
--- a/doc/src/sgml/ref/create_foreign_table.sgml
+++ b/doc/src/sgml/ref/create_foreign_table.sgml
@@ -19,7 +19,8 @@
<refsynopsisdiv>
<synopsis>
CREATE FOREIGN TABLE [ IF NOT EXISTS ] <replaceable class="PARAMETER">table_name</replaceable> ( [
- <replaceable class="PARAMETER">column_name</replaceable> <replaceable class="PARAMETER">data_type</replaceable> [ OPTIONS ( <replaceable class="PARAMETER">option</replaceable> '<replaceable class="PARAMETER">value</replaceable>' [, ... ] ) ] [ COLLATE <replaceable>collation</replaceable> ] [ <replaceable class="PARAMETER">column_constraint</replaceable> [ ... ] ]
+ { <replaceable class="PARAMETER">column_name</replaceable> <replaceable class="PARAMETER">data_type</replaceable> [ OPTIONS ( <replaceable class="PARAMETER">option</replaceable> '<replaceable class="PARAMETER">value</replaceable>' [, ... ] ) ] [ COLLATE <replaceable>collation</replaceable> ] [ <replaceable class="PARAMETER">column_constraint</replaceable> [ ... ] ]
+ | <replaceable>table_constraint</replaceable> }
[, ... ]
] )
SERVER <replaceable class="parameter">server_name</replaceable>
@@ -30,7 +31,13 @@ CREATE FOREIGN TABLE [ IF NOT EXISTS ] <replaceable class="PARAMETER">table_name
[ CONSTRAINT <replaceable class="PARAMETER">constraint_name</replaceable> ]
{ NOT NULL |
NULL |
+ CHECK ( <replaceable class="PARAMETER">expression</replaceable> ) |
DEFAULT <replaceable>default_expr</replaceable> }
+
+<phrase>and <replaceable class="PARAMETER">table_constraint</replaceable> is:</phrase>
+
+[ CONSTRAINT <replaceable class="PARAMETER">constraint_name</replaceable> ]
+CHECK ( <replaceable class="PARAMETER">expression</replaceable> )
</synopsis>
</refsynopsisdiv>
@@ -137,6 +144,28 @@ CREATE FOREIGN TABLE [ IF NOT EXISTS ] <replaceable class="PARAMETER">table_name
</listitem>
</varlistentry>
+ <varlistentry>
+ <term><literal>CHECK ( <replaceable class="PARAMETER">expression</replaceable> )</literal></term>
+ <listitem>
+ <para>
+ The <literal>CHECK</> clause specifies an expression producing a
+ Boolean result which each row in the foreign table is expected
+ to satisfy; that is, the expression should produce TRUE or UNKNOWN,
+ never FALSE, for all rows in the foreign table.
+ A check constraint specified as a column constraint should
+ reference that column's value only, while an expression
+ appearing in a table constraint can reference multiple columns.
+ </para>
+
+ <para>
+ Currently, <literal>CHECK</literal> expressions cannot contain
+ subqueries nor refer to variables other than columns of the
+ current row. The system column <literal>tableoid</literal>
+ may be referenced, but not any other system column.
+ </para>
+ </listitem>
+ </varlistentry>
+
<varlistentry>
<term><literal>DEFAULT
<replaceable>default_expr</replaceable></literal></term>
@@ -187,6 +216,40 @@ CREATE FOREIGN TABLE [ IF NOT EXISTS ] <replaceable class="PARAMETER">table_name
</refsect1>
+ <refsect1>
+ <title>Notes</title>
+
+ <para>
+ Constraints on foreign tables (such as <literal>CHECK</>
+ or <literal>NOT NULL</> clauses) are not enforced by the
+ core <productname>PostgreSQL</> system, and most foreign data wrappers
+ do not attempt to enforce them either; that is, the constraint is
+ simply assumed to hold true. There would be little point in such
+ enforcement since it would only apply to rows inserted or updated via
+ the foreign table, and not to rows modified by other means, such as
+ directly on the remote server. Instead, a constraint attached to a
+ foreign table should represent a constraint that is being enforced by
+ the remote server.
+ </para>
+
+ <para>
+ Some special-purpose foreign data wrappers might be the only access
+ mechanism for the data they access, and in that case it might be
+ appropriate for the foreign data wrapper itself to perform constraint
+ enforcement. But you should not assume that a wrapper does that
+ unless its documentation says so.
+ </para>
+
+ <para>
+ Although <productname>PostgreSQL</> does not attempt to enforce
+ constraints on foreign tables, it does assume that they are correct
+ for purposes of query optimization. If there are rows visible in the
+ foreign table that do not satisfy a declared constraint, queries on
+ the table might produce incorrect answers. It is the user's
+ responsibility to ensure that the constraint definition matches
+ reality.
+ </para>
+ </refsect1>
<refsect1 id="SQL-CREATEFOREIGNTABLE-examples">
<title>Examples</title>
diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index e523ee923a4ea401d73dff6ac56e5d9b4d2453e2..e360482e1dea94a5bc1ca741fdcc95bb60124912 100644
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -1091,7 +1091,7 @@ heap_create_with_catalog(const char *relname,
*/
if (!OidIsValid(relid))
{
- /* Use binary-upgrade override for pg_class.oid/relfilenode? */
+ /* Use binary-upgrade override for pg_class.oid/relfilenode? */
if (IsBinaryUpgrade &&
(relkind == RELKIND_RELATION || relkind == RELKIND_SEQUENCE ||
relkind == RELKIND_VIEW || relkind == RELKIND_MATVIEW ||
@@ -2244,6 +2244,13 @@ AddRelationNewConstraints(Relation rel,
expr = stringToNode(cdef->cooked_expr);
}
+ /* Don't allow NOT VALID for foreign tables */
+ if (cdef->skip_validation &&
+ rel->rd_rel->relkind == RELKIND_FOREIGN_TABLE)
+ ereport(ERROR,
+ (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+ errmsg("CHECK constraints on foreign tables cannot be marked NOT VALID")));
+
/*
* Check name uniqueness, or generate a name if none was given.
*/
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 1e737a01c9f0719fdb514c0b625ee859dfe7fa78..81c5ab27c966585b9a7a6a611f5dcc4ab6bf3ad5 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -479,10 +479,6 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId)
ereport(ERROR,
(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
errmsg("ON COMMIT can only be used on temporary tables")));
- if (stmt->constraints != NIL && relkind == RELKIND_FOREIGN_TABLE)
- ereport(ERROR,
- (errcode(ERRCODE_WRONG_OBJECT_TYPE),
- errmsg("constraints are not supported on foreign tables")));
/*
* Look up the namespace in which we are supposed to create the relation,
@@ -3154,7 +3150,7 @@ ATPrepCmd(List **wqueue, Relation rel, AlterTableCmd *cmd,
pass = AT_PASS_ADD_INDEX;
break;
case AT_AddConstraint: /* ADD CONSTRAINT */
- ATSimplePermissions(rel, ATT_TABLE);
+ ATSimplePermissions(rel, ATT_TABLE | ATT_FOREIGN_TABLE);
/* Recursion occurs during execution phase */
/* No command-specific prep needed except saving recurse flag */
if (recurse)
@@ -3168,7 +3164,7 @@ ATPrepCmd(List **wqueue, Relation rel, AlterTableCmd *cmd,
pass = AT_PASS_ADD_CONSTR;
break;
case AT_DropConstraint: /* DROP CONSTRAINT */
- ATSimplePermissions(rel, ATT_TABLE);
+ ATSimplePermissions(rel, ATT_TABLE | ATT_FOREIGN_TABLE);
/* Recursion occurs during execution phase */
/* No command-specific prep needed except saving recurse flag */
if (recurse)
diff --git a/src/backend/parser/parse_utilcmd.c b/src/backend/parser/parse_utilcmd.c
index 7c1939f9c45cc6febceb0a9fee9d5b55ceb06df1..b9fbb5b6efdf53b3499153a0fca83b22835df4a4 100644
--- a/src/backend/parser/parse_utilcmd.c
+++ b/src/backend/parser/parse_utilcmd.c
@@ -515,21 +515,23 @@ transformColumnDefinition(CreateStmtContext *cxt, ColumnDef *column)
break;
case CONSTR_CHECK:
+ cxt->ckconstraints = lappend(cxt->ckconstraints, constraint);
+ break;
+
+ case CONSTR_PRIMARY:
if (cxt->isforeign)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
- errmsg("constraints are not supported on foreign tables"),
+ errmsg("primary key constraints are not supported on foreign tables"),
parser_errposition(cxt->pstate,
constraint->location)));
- cxt->ckconstraints = lappend(cxt->ckconstraints, constraint);
- break;
+ /* FALL THRU */
- case CONSTR_PRIMARY:
case CONSTR_UNIQUE:
if (cxt->isforeign)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
- errmsg("constraints are not supported on foreign tables"),
+ errmsg("unique constraints are not supported on foreign tables"),
parser_errposition(cxt->pstate,
constraint->location)));
if (constraint->keys == NIL)
@@ -546,7 +548,7 @@ transformColumnDefinition(CreateStmtContext *cxt, ColumnDef *column)
if (cxt->isforeign)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
- errmsg("constraints are not supported on foreign tables"),
+ errmsg("foreign key constraints are not supported on foreign tables"),
parser_errposition(cxt->pstate,
constraint->location)));
@@ -605,18 +607,35 @@ transformColumnDefinition(CreateStmtContext *cxt, ColumnDef *column)
static void
transformTableConstraint(CreateStmtContext *cxt, Constraint *constraint)
{
- if (cxt->isforeign)
- ereport(ERROR,
- (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
- errmsg("constraints are not supported on foreign tables"),
- parser_errposition(cxt->pstate,
- constraint->location)));
-
switch (constraint->contype)
{
case CONSTR_PRIMARY:
+ if (cxt->isforeign)
+ ereport(ERROR,
+ (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+ errmsg("primary key constraints are not supported on foreign tables"),
+ parser_errposition(cxt->pstate,
+ constraint->location)));
+ cxt->ixconstraints = lappend(cxt->ixconstraints, constraint);
+ break;
+
case CONSTR_UNIQUE:
+ if (cxt->isforeign)
+ ereport(ERROR,
+ (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+ errmsg("unique constraints are not supported on foreign tables"),
+ parser_errposition(cxt->pstate,
+ constraint->location)));
+ cxt->ixconstraints = lappend(cxt->ixconstraints, constraint);
+ break;
+
case CONSTR_EXCLUSION:
+ if (cxt->isforeign)
+ ereport(ERROR,
+ (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+ errmsg("exclusion constraints are not supported on foreign tables"),
+ parser_errposition(cxt->pstate,
+ constraint->location)));
cxt->ixconstraints = lappend(cxt->ixconstraints, constraint);
break;
@@ -625,6 +644,12 @@ transformTableConstraint(CreateStmtContext *cxt, Constraint *constraint)
break;
case CONSTR_FOREIGN:
+ if (cxt->isforeign)
+ ereport(ERROR,
+ (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+ errmsg("foreign key constraints are not supported on foreign tables"),
+ parser_errposition(cxt->pstate,
+ constraint->location)));
cxt->fkconstraints = lappend(cxt->fkconstraints, constraint);
break;
diff --git a/src/test/regress/expected/foreign_data.out b/src/test/regress/expected/foreign_data.out
index e4dedb0c3ba2ca091da60a105d00f8185eeb27c3..9bca4402f6edfe54c9ef3b7ab4341bad8d7ea2aa 100644
--- a/src/test/regress/expected/foreign_data.out
+++ b/src/test/regress/expected/foreign_data.out
@@ -669,9 +669,37 @@ ERROR: syntax error at or near "WITH OIDS"
LINE 1: CREATE FOREIGN TABLE ft1 () SERVER s0 WITH OIDS;
^
CREATE FOREIGN TABLE ft1 (
- c1 integer OPTIONS ("param 1" 'val1') NOT NULL,
+ c1 integer OPTIONS ("param 1" 'val1') PRIMARY KEY,
+ c2 text OPTIONS (param2 'val2', param3 'val3'),
+ c3 date
+) SERVER s0 OPTIONS (delimiter ',', quote '"', "be quoted" 'value'); -- ERROR
+ERROR: primary key constraints are not supported on foreign tables
+LINE 2: c1 integer OPTIONS ("param 1" 'val1') PRIMARY KEY,
+ ^
+CREATE TABLE ref_table (id integer PRIMARY KEY);
+CREATE FOREIGN TABLE ft1 (
+ c1 integer OPTIONS ("param 1" 'val1') REFERENCES ref_table (id),
c2 text OPTIONS (param2 'val2', param3 'val3'),
c3 date
+) SERVER s0 OPTIONS (delimiter ',', quote '"', "be quoted" 'value'); -- ERROR
+ERROR: foreign key constraints are not supported on foreign tables
+LINE 2: c1 integer OPTIONS ("param 1" 'val1') REFERENCES ref_table ...
+ ^
+DROP TABLE ref_table;
+CREATE FOREIGN TABLE ft1 (
+ c1 integer OPTIONS ("param 1" 'val1') NOT NULL,
+ c2 text OPTIONS (param2 'val2', param3 'val3'),
+ c3 date,
+ UNIQUE (c3)
+) SERVER s0 OPTIONS (delimiter ',', quote '"', "be quoted" 'value'); -- ERROR
+ERROR: unique constraints are not supported on foreign tables
+LINE 5: UNIQUE (c3)
+ ^
+CREATE FOREIGN TABLE ft1 (
+ c1 integer OPTIONS ("param 1" 'val1') NOT NULL,
+ c2 text OPTIONS (param2 'val2', param3 'val3') CHECK (c2 <> ''),
+ c3 date,
+ CHECK (c3 BETWEEN '1994-01-01'::date AND '1994-01-31'::date)
) SERVER s0 OPTIONS (delimiter ',', quote '"', "be quoted" 'value');
COMMENT ON FOREIGN TABLE ft1 IS 'ft1';
COMMENT ON COLUMN ft1.c1 IS 'ft1.c1';
@@ -682,6 +710,9 @@ COMMENT ON COLUMN ft1.c1 IS 'ft1.c1';
c1 | integer | not null | ("param 1" 'val1') | plain | | ft1.c1
c2 | text | | (param2 'val2', param3 'val3') | extended | |
c3 | date | | | plain | |
+Check constraints:
+ "ft1_c2_check" CHECK (c2 <> ''::text)
+ "ft1_c3_check" CHECK (c3 >= '01-01-1994'::date AND c3 <= '01-31-1994'::date)
Server: s0
FDW Options: (delimiter ',', quote '"', "be quoted" 'value')
@@ -740,6 +771,9 @@ ALTER FOREIGN TABLE ft1 ALTER COLUMN c8 SET STATISTICS -1;
c8 | text | | (p2 'V2') | extended | |
c9 | integer | | | plain | |
c10 | integer | | (p1 'v1') | plain | |
+Check constraints:
+ "ft1_c2_check" CHECK (c2 <> ''::text)
+ "ft1_c3_check" CHECK (c3 >= '01-01-1994'::date AND c3 <= '01-31-1994'::date)
Server: s0
FDW Options: (delimiter ',', quote '"', "be quoted" 'value')
@@ -748,16 +782,20 @@ CREATE TABLE use_ft1_column_type (x ft1);
ALTER FOREIGN TABLE ft1 ALTER COLUMN c8 SET DATA TYPE integer; -- ERROR
ERROR: cannot alter foreign table "ft1" because column "use_ft1_column_type.x" uses its row type
DROP TABLE use_ft1_column_type;
-ALTER FOREIGN TABLE ft1 ADD CONSTRAINT ft1_c9_check CHECK (c9 < 0); -- ERROR
-ERROR: constraints are not supported on foreign tables
-LINE 1: ALTER FOREIGN TABLE ft1 ADD CONSTRAINT ft1_c9_check CHECK (c...
+ALTER FOREIGN TABLE ft1 ADD PRIMARY KEY (c7); -- ERROR
+ERROR: primary key constraints are not supported on foreign tables
+LINE 1: ALTER FOREIGN TABLE ft1 ADD PRIMARY KEY (c7);
^
-ALTER FOREIGN TABLE ft1 DROP CONSTRAINT no_const; -- ERROR
+ALTER FOREIGN TABLE ft1 ADD CONSTRAINT ft1_c9_check CHECK (c9 < 0) NOT VALID; -- ERROR
+ERROR: CHECK constraints on foreign tables cannot be marked NOT VALID
+ALTER FOREIGN TABLE ft1 ADD CONSTRAINT ft1_c9_check CHECK (c9 < 0);
+ALTER FOREIGN TABLE ft1 ALTER CONSTRAINT ft1_c9_check DEFERRABLE; -- ERROR
ERROR: "ft1" is not a table
+ALTER FOREIGN TABLE ft1 DROP CONSTRAINT ft1_c9_check;
+ALTER FOREIGN TABLE ft1 DROP CONSTRAINT no_const; -- ERROR
+ERROR: constraint "no_const" of relation "ft1" does not exist
ALTER FOREIGN TABLE ft1 DROP CONSTRAINT IF EXISTS no_const;
-ERROR: "ft1" is not a table
-ALTER FOREIGN TABLE ft1 DROP CONSTRAINT ft1_c1_check;
-ERROR: "ft1" is not a table
+NOTICE: constraint "no_const" of relation "ft1" does not exist, skipping
ALTER FOREIGN TABLE ft1 SET WITH OIDS; -- ERROR
ERROR: "ft1" is not a table
ALTER FOREIGN TABLE ft1 OWNER TO regress_test_role;
@@ -785,6 +823,9 @@ ALTER FOREIGN TABLE foreign_schema.ft1 RENAME TO foreign_table_1;
c7 | integer | | (p1 'v1', p2 'v2')
c8 | text | | (p2 'V2')
c10 | integer | | (p1 'v1')
+Check constraints:
+ "ft1_c2_check" CHECK (c2 <> ''::text)
+ "ft1_c3_check" CHECK (c3 >= '01-01-1994'::date AND c3 <= '01-31-1994'::date)
Server: s0
FDW Options: (quote '~', "be quoted" 'value', escape '@')
diff --git a/src/test/regress/sql/foreign_data.sql b/src/test/regress/sql/foreign_data.sql
index de9dbc8f386c3f55ff37c19be54dd7586a1d7cd2..b4b999d444e200c5567d445035cf38ac31eaa004 100644
--- a/src/test/regress/sql/foreign_data.sql
+++ b/src/test/regress/sql/foreign_data.sql
@@ -269,9 +269,28 @@ CREATE FOREIGN TABLE ft1 (); -- ERROR
CREATE FOREIGN TABLE ft1 () SERVER no_server; -- ERROR
CREATE FOREIGN TABLE ft1 () SERVER s0 WITH OIDS; -- ERROR
CREATE FOREIGN TABLE ft1 (
- c1 integer OPTIONS ("param 1" 'val1') NOT NULL,
+ c1 integer OPTIONS ("param 1" 'val1') PRIMARY KEY,
c2 text OPTIONS (param2 'val2', param3 'val3'),
c3 date
+) SERVER s0 OPTIONS (delimiter ',', quote '"', "be quoted" 'value'); -- ERROR
+CREATE TABLE ref_table (id integer PRIMARY KEY);
+CREATE FOREIGN TABLE ft1 (
+ c1 integer OPTIONS ("param 1" 'val1') REFERENCES ref_table (id),
+ c2 text OPTIONS (param2 'val2', param3 'val3'),
+ c3 date
+) SERVER s0 OPTIONS (delimiter ',', quote '"', "be quoted" 'value'); -- ERROR
+DROP TABLE ref_table;
+CREATE FOREIGN TABLE ft1 (
+ c1 integer OPTIONS ("param 1" 'val1') NOT NULL,
+ c2 text OPTIONS (param2 'val2', param3 'val3'),
+ c3 date,
+ UNIQUE (c3)
+) SERVER s0 OPTIONS (delimiter ',', quote '"', "be quoted" 'value'); -- ERROR
+CREATE FOREIGN TABLE ft1 (
+ c1 integer OPTIONS ("param 1" 'val1') NOT NULL,
+ c2 text OPTIONS (param2 'val2', param3 'val3') CHECK (c2 <> ''),
+ c3 date,
+ CHECK (c3 BETWEEN '1994-01-01'::date AND '1994-01-31'::date)
) SERVER s0 OPTIONS (delimiter ',', quote '"', "be quoted" 'value');
COMMENT ON FOREIGN TABLE ft1 IS 'ft1';
COMMENT ON COLUMN ft1.c1 IS 'ft1.c1';
@@ -314,10 +333,13 @@ ALTER FOREIGN TABLE ft1 ALTER COLUMN c8 SET STATISTICS -1;
CREATE TABLE use_ft1_column_type (x ft1);
ALTER FOREIGN TABLE ft1 ALTER COLUMN c8 SET DATA TYPE integer; -- ERROR
DROP TABLE use_ft1_column_type;
-ALTER FOREIGN TABLE ft1 ADD CONSTRAINT ft1_c9_check CHECK (c9 < 0); -- ERROR
+ALTER FOREIGN TABLE ft1 ADD PRIMARY KEY (c7); -- ERROR
+ALTER FOREIGN TABLE ft1 ADD CONSTRAINT ft1_c9_check CHECK (c9 < 0) NOT VALID; -- ERROR
+ALTER FOREIGN TABLE ft1 ADD CONSTRAINT ft1_c9_check CHECK (c9 < 0);
+ALTER FOREIGN TABLE ft1 ALTER CONSTRAINT ft1_c9_check DEFERRABLE; -- ERROR
+ALTER FOREIGN TABLE ft1 DROP CONSTRAINT ft1_c9_check;
ALTER FOREIGN TABLE ft1 DROP CONSTRAINT no_const; -- ERROR
ALTER FOREIGN TABLE ft1 DROP CONSTRAINT IF EXISTS no_const;
-ALTER FOREIGN TABLE ft1 DROP CONSTRAINT ft1_c1_check;
ALTER FOREIGN TABLE ft1 SET WITH OIDS; -- ERROR
ALTER FOREIGN TABLE ft1 OWNER TO regress_test_role;
ALTER FOREIGN TABLE ft1 OPTIONS (DROP delimiter, SET quote '~', ADD escape '@');