<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>table_constraint</replaceable> }
+ | <replaceable>table_constraint</replaceable>
+ | LIKE <replaceable>source_table</replaceable> [ <replaceable>like_option</replaceable> ... ] }
[, ... ]
] )
[ INHERITS ( <replaceable>parent_table</replaceable> [, ... ] ) ]
CHECK ( <replaceable class="parameter">expression</replaceable> ) [ NO INHERIT ] }
[ ENFORCED | NOT ENFORCED ]
+<phrase>and <replaceable class="parameter">like_option</replaceable> is:</phrase>
+
+{ INCLUDING | EXCLUDING } { COMMENTS | CONSTRAINTS | DEFAULTS | GENERATED | STATISTICS | ALL }
+
<phrase>and <replaceable class="parameter">partition_bound_spec</replaceable> is:</phrase>
IN ( <replaceable class="parameter">partition_bound_expr</replaceable> [, ...] ) |
</listitem>
</varlistentry>
+ <varlistentry>
+ <term><literal>LIKE <replaceable>source_table</replaceable> [ <replaceable>like_option</replaceable> ... ]</literal></term>
+ <listitem>
+ <para>
+ The <literal>LIKE</literal> clause specifies a table from which
+ the new table automatically copies all column names, their data types,
+ and their not-null constraints.
+ </para>
+ <para>
+ Unlike <literal>INHERITS</literal>, the new table and original table
+ are completely decoupled after creation is complete. Changes to the
+ original table will not be applied to the new table, and it is not
+ possible to include data of the new table in scans of the original
+ table.
+ </para>
+ <para>
+ Also unlike <literal>INHERITS</literal>, columns and
+ constraints copied by <literal>LIKE</literal> are not merged with similarly
+ named columns and constraints.
+ If the same name is specified explicitly or in another
+ <literal>LIKE</literal> clause, an error is signaled.
+ </para>
+ <para>
+ The optional <replaceable>like_option</replaceable> clauses specify
+ which additional properties of the original table to copy. Specifying
+ <literal>INCLUDING</literal> copies the property, specifying
+ <literal>EXCLUDING</literal> omits the property.
+ <literal>EXCLUDING</literal> is the default. If multiple specifications
+ are made for the same kind of object, the last one is used. The
+ available options are:
+
+ <variablelist>
+ <varlistentry>
+ <term><literal>INCLUDING COMMENTS</literal></term>
+ <listitem>
+ <para>
+ Comments for the copied columns, constraints, and indexes will be
+ copied. The default behavior is to exclude comments, resulting in
+ the copied columns and constraints in the new table having no
+ comments.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><literal>INCLUDING CONSTRAINTS</literal></term>
+ <listitem>
+ <para>
+ <literal>CHECK</literal> constraints will be copied. No distinction
+ is made between column constraints and table constraints. Not-null
+ constraints are always copied to the new table.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><literal>INCLUDING DEFAULTS</literal></term>
+ <listitem>
+ <para>
+ Default expressions for the copied column definitions will be
+ copied. Otherwise, default expressions are not copied, resulting in
+ the copied columns in the new table having null defaults. Note that
+ copying defaults that call database-modification functions, such as
+ <function>nextval</function>, may create a functional linkage
+ between the original and new tables.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><literal>INCLUDING GENERATED</literal></term>
+ <listitem>
+ <para>
+ Any generation expressions of copied column definitions will be
+ copied. By default, new columns will be regular base columns.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><literal>INCLUDING STATISTICS</literal></term>
+ <listitem>
+ <para>
+ Extended statistics are copied to the new table.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><literal>INCLUDING ALL</literal></term>
+ <listitem>
+ <para>
+ <literal>INCLUDING ALL</literal> is an abbreviated form selecting
+ all the available individual options. (It could be useful to write
+ individual <literal>EXCLUDING</literal> clauses after
+ <literal>INCLUDING ALL</literal> to select all but some specific
+ options.)
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </para>
+ </listitem>
+ </varlistentry>
+
<varlistentry>
<term><literal>CONSTRAINT <replaceable class="parameter">constraint_name</replaceable></literal></term>
<listitem>
The ability to specify column default values is also
a <productname>PostgreSQL</productname> extension. Table inheritance, in the form
defined by <productname>PostgreSQL</productname>, is nonstandard.
+ The <literal>LIKE</literal> clause, as supported in this command, is
+ nonstandard.
</para>
</refsect1>
* process at this point, add the TableLikeClause to cxt->likeclauses, which
* will cause utility.c to call expandTableLikeClause() after the new
* table has been created.
+ *
+ * Some options are ignored. For example, as foreign tables have no storage,
+ * these INCLUDING options have no effect: STORAGE, COMPRESSION, IDENTITY
+ * and INDEXES. Similarly, INCLUDING INDEXES is ignored from a view.
*/
static void
transformTableLikeClause(CreateStmtContext *cxt, TableLikeClause *table_like_clause)
setup_parser_errposition_callback(&pcbstate, cxt->pstate,
table_like_clause->relation->location);
- /* we could support LIKE in many cases, but worry about it another day */
- if (cxt->isforeign)
- ereport(ERROR,
- (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
- errmsg("LIKE is not supported for creating foreign tables")));
-
/* Open the relation referenced by the LIKE clause */
relation = relation_openrv(table_like_clause->relation, AccessShareLock);
* Copy identity if requested
*/
if (attribute->attidentity &&
- (table_like_clause->options & CREATE_TABLE_LIKE_IDENTITY))
+ (table_like_clause->options & CREATE_TABLE_LIKE_IDENTITY) &&
+ !cxt->isforeign)
{
Oid seq_relid;
List *seq_options;
}
/* Likewise, copy storage if requested */
- if (table_like_clause->options & CREATE_TABLE_LIKE_STORAGE)
+ if ((table_like_clause->options & CREATE_TABLE_LIKE_STORAGE) &&
+ !cxt->isforeign)
def->storage = attribute->attstorage;
else
def->storage = 0;
/* Likewise, copy compression if requested */
- if ((table_like_clause->options & CREATE_TABLE_LIKE_COMPRESSION) != 0
- && CompressionMethodIsValid(attribute->attcompression))
+ if ((table_like_clause->options & CREATE_TABLE_LIKE_COMPRESSION) != 0 &&
+ CompressionMethodIsValid(attribute->attcompression) &&
+ !cxt->isforeign)
def->compression =
pstrdup(GetCompressionMethodName(attribute->attcompression));
else
* Process indexes if required.
*/
if ((table_like_clause->options & CREATE_TABLE_LIKE_INDEXES) &&
- relation->rd_rel->relhasindex)
+ relation->rd_rel->relhasindex &&
+ childrel->rd_rel->relkind != RELKIND_FOREIGN_TABLE)
{
List *parent_indexes;
ListCell *l;
DROP VIEW ctlv1;
DROP TABLE IF EXISTS ctlt4, ctlt10, ctlt11, ctlt11a, ctlt12;
NOTICE: table "ctlt10" does not exist, skipping
+--
+-- CREATE FOREIGN TABLE LIKE
+--
+CREATE FOREIGN DATA WRAPPER ctl_dummy;
+CREATE SERVER ctl_s0 FOREIGN DATA WRAPPER ctl_dummy;
+CREATE TABLE ctl_table(a int PRIMARY KEY,
+ b varchar COMPRESSION pglz,
+ c int GENERATED ALWAYS AS (a * 2) STORED,
+ d bigint GENERATED ALWAYS AS IDENTITY,
+ e int DEFAULT 1);
+CREATE INDEX ctl_table_a_key ON ctl_table(a);
+COMMENT ON COLUMN ctl_table.b IS 'Column b';
+CREATE STATISTICS ctl_table_stat ON a,b FROM ctl_table;
+ALTER TABLE ctl_table ADD CONSTRAINT foo CHECK (b = 'text');
+ALTER TABLE ctl_table ALTER COLUMN b SET STORAGE MAIN;
+\d+ ctl_table
+ Table "public.ctl_table"
+ Column | Type | Collation | Nullable | Default | Storage | Stats target | Description
+--------+-------------------+-----------+----------+------------------------------------+---------+--------------+-------------
+ a | integer | | not null | | plain | |
+ b | character varying | | | | main | | Column b
+ c | integer | | | generated always as (a * 2) stored | plain | |
+ d | bigint | | not null | generated always as identity | plain | |
+ e | integer | | | 1 | plain | |
+Indexes:
+ "ctl_table_pkey" PRIMARY KEY, btree (a)
+ "ctl_table_a_key" btree (a)
+Check constraints:
+ "foo" CHECK (b::text = 'text'::text)
+Statistics objects:
+ "public.ctl_table_stat" ON a, b FROM ctl_table
+Not-null constraints:
+ "ctl_table_a_not_null" NOT NULL "a"
+ "ctl_table_d_not_null" NOT NULL "d"
+
+-- Test EXCLUDING ALL
+CREATE FOREIGN TABLE ctl_foreign_table1(LIKE ctl_table EXCLUDING ALL) SERVER ctl_s0;
+\d+ ctl_foreign_table1
+ Foreign table "public.ctl_foreign_table1"
+ Column | Type | Collation | Nullable | Default | FDW options | Storage | Stats target | Description
+--------+-------------------+-----------+----------+---------+-------------+----------+--------------+-------------
+ a | integer | | not null | | | plain | |
+ b | character varying | | | | | extended | |
+ c | integer | | | | | plain | |
+ d | bigint | | not null | | | plain | |
+ e | integer | | | | | plain | |
+Not-null constraints:
+ "ctl_table_a_not_null" NOT NULL "a"
+ "ctl_table_d_not_null" NOT NULL "d"
+Server: ctl_s0
+
+-- \d+ does not report the value of attcompression for a foreign table, so
+-- check separately.
+SELECT attname, attcompression FROM pg_attribute
+ WHERE attrelid = 'ctl_foreign_table1'::regclass and attnum > 0 ORDER BY attnum;
+ attname | attcompression
+---------+----------------
+ a |
+ b |
+ c |
+ d |
+ e |
+(5 rows)
+
+-- Test INCLUDING ALL
+-- INDEXES, IDENTITY, COMPRESSION, STORAGE are not copied.
+CREATE FOREIGN TABLE ctl_foreign_table2(LIKE ctl_table INCLUDING ALL) SERVER ctl_s0;
+\d+ ctl_foreign_table2
+ Foreign table "public.ctl_foreign_table2"
+ Column | Type | Collation | Nullable | Default | FDW options | Storage | Stats target | Description
+--------+-------------------+-----------+----------+------------------------------------+-------------+----------+--------------+-------------
+ a | integer | | not null | | | plain | |
+ b | character varying | | | | | extended | | Column b
+ c | integer | | | generated always as (a * 2) stored | | plain | |
+ d | bigint | | not null | | | plain | |
+ e | integer | | | 1 | | plain | |
+Check constraints:
+ "foo" CHECK (b::text = 'text'::text)
+Statistics objects:
+ "public.ctl_foreign_table2_a_b_stat" ON a, b FROM ctl_foreign_table2
+Not-null constraints:
+ "ctl_table_a_not_null" NOT NULL "a"
+ "ctl_table_d_not_null" NOT NULL "d"
+Server: ctl_s0
+
+-- \d+ does not report the value of attcompression for a foreign table, so
+-- check separately.
+SELECT attname, attcompression FROM pg_attribute
+ WHERE attrelid = 'ctl_foreign_table2'::regclass and attnum > 0 ORDER BY attnum;
+ attname | attcompression
+---------+----------------
+ a |
+ b |
+ c |
+ d |
+ e |
+(5 rows)
+
+DROP TABLE ctl_table;
+DROP FOREIGN TABLE ctl_foreign_table1;
+DROP FOREIGN TABLE ctl_foreign_table2;
+DROP FOREIGN DATA WRAPPER ctl_dummy CASCADE;
+NOTICE: drop cascades to server ctl_s0
DROP TYPE ctlty1;
DROP VIEW ctlv1;
DROP TABLE IF EXISTS ctlt4, ctlt10, ctlt11, ctlt11a, ctlt12;
+
+--
+-- CREATE FOREIGN TABLE LIKE
+--
+CREATE FOREIGN DATA WRAPPER ctl_dummy;
+CREATE SERVER ctl_s0 FOREIGN DATA WRAPPER ctl_dummy;
+
+CREATE TABLE ctl_table(a int PRIMARY KEY,
+ b varchar COMPRESSION pglz,
+ c int GENERATED ALWAYS AS (a * 2) STORED,
+ d bigint GENERATED ALWAYS AS IDENTITY,
+ e int DEFAULT 1);
+
+CREATE INDEX ctl_table_a_key ON ctl_table(a);
+COMMENT ON COLUMN ctl_table.b IS 'Column b';
+CREATE STATISTICS ctl_table_stat ON a,b FROM ctl_table;
+ALTER TABLE ctl_table ADD CONSTRAINT foo CHECK (b = 'text');
+ALTER TABLE ctl_table ALTER COLUMN b SET STORAGE MAIN;
+
+\d+ ctl_table
+
+-- Test EXCLUDING ALL
+CREATE FOREIGN TABLE ctl_foreign_table1(LIKE ctl_table EXCLUDING ALL) SERVER ctl_s0;
+\d+ ctl_foreign_table1
+-- \d+ does not report the value of attcompression for a foreign table, so
+-- check separately.
+SELECT attname, attcompression FROM pg_attribute
+ WHERE attrelid = 'ctl_foreign_table1'::regclass and attnum > 0 ORDER BY attnum;
+
+-- Test INCLUDING ALL
+-- INDEXES, IDENTITY, COMPRESSION, STORAGE are not copied.
+CREATE FOREIGN TABLE ctl_foreign_table2(LIKE ctl_table INCLUDING ALL) SERVER ctl_s0;
+\d+ ctl_foreign_table2
+-- \d+ does not report the value of attcompression for a foreign table, so
+-- check separately.
+SELECT attname, attcompression FROM pg_attribute
+ WHERE attrelid = 'ctl_foreign_table2'::regclass and attnum > 0 ORDER BY attnum;
+
+DROP TABLE ctl_table;
+DROP FOREIGN TABLE ctl_foreign_table1;
+DROP FOREIGN TABLE ctl_foreign_table2;
+DROP FOREIGN DATA WRAPPER ctl_dummy CASCADE;
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