1ALTER TABLE(7) PostgreSQL 9.2.24 Documentation ALTER TABLE(7)
2
6 ALTER_TABLE - change the definition of a table
7
9 ALTER TABLE [ IF EXISTS ] [ ONLY ] name [ * ]
10 action [, ... ]
11 ALTER TABLE [ IF EXISTS ] [ ONLY ] name [ * ]
12 RENAME [ COLUMN ] column_name TO new_column_name
13 ALTER TABLE [ IF EXISTS ] [ ONLY ] name [ * ]
14 RENAME CONSTRAINT constraint_name TO new_constraint_name
15 ALTER TABLE [ IF EXISTS ] name
16 RENAME TO new_name
17 ALTER TABLE [ IF EXISTS ] name
18 SET SCHEMA new_schema
19 where action is one of:
21 ADD [ COLUMN ] column_name data_type [ COLLATE collation ] [ column_constraint [ ... ] ]
23 DROP [ COLUMN ] [ IF EXISTS ] column_name [ RESTRICT | CASCADE ]
24 ALTER [ COLUMN ] column_name [ SET DATA ] TYPE data_type [ COLLATE collation ] [ USING expression ]
25 ALTER [ COLUMN ] column_name SET DEFAULT expression
26 ALTER [ COLUMN ] column_name DROP DEFAULT
27 ALTER [ COLUMN ] column_name { SET | DROP } NOT NULL
28 ALTER [ COLUMN ] column_name SET STATISTICS integer
29 ALTER [ COLUMN ] column_name SET ( attribute_option = value [, ... ] )
30 ALTER [ COLUMN ] column_name RESET ( attribute_option [, ... ] )
31 ALTER [ COLUMN ] column_name SET STORAGE { PLAIN | EXTERNAL | EXTENDED | MAIN }
32 ADD table_constraint [ NOT VALID ]
33 ADD table_constraint_using_index
34 VALIDATE CONSTRAINT constraint_name
35 DROP CONSTRAINT [ IF EXISTS ] constraint_name [ RESTRICT | CASCADE ]
36 DISABLE TRIGGER [ trigger_name | ALL | USER ]
37 ENABLE TRIGGER [ trigger_name | ALL | USER ]
38 ENABLE REPLICA TRIGGER trigger_name
39 ENABLE ALWAYS TRIGGER trigger_name
40 DISABLE RULE rewrite_rule_name
41 ENABLE RULE rewrite_rule_name
42 ENABLE REPLICA RULE rewrite_rule_name
43 ENABLE ALWAYS RULE rewrite_rule_name
44 CLUSTER ON index_name
45 SET WITHOUT CLUSTER
46 SET WITH OIDS
47 SET WITHOUT OIDS
48 SET ( storage_parameter = value [, ... ] )
49 RESET ( storage_parameter [, ... ] )
50 INHERIT parent_table
51 NO INHERIT parent_table
52 OF type_name
53 NOT OF
54 OWNER TO new_owner
55 SET TABLESPACE new_tablespace
56 and table_constraint_using_index is:
58 [ CONSTRAINT constraint_name ]
60 { UNIQUE | PRIMARY KEY } USING INDEX index_name
61 [ DEFERRABLE | NOT DEFERRABLE ] [ INITIALLY DEFERRED | INITIALLY IMMEDIATE ]
62
64 ALTER TABLE changes the definition of an existing table. There are
65 several subforms:
66 ADD COLUMN
68 This form adds a new column to the table, using the same syntax as
69 CREATE TABLE (CREATE_TABLE(7)).
70 DROP COLUMN [ IF EXISTS ]
72 This form drops a column from a table. Indexes and table
73 constraints involving the column will be automatically dropped as
74 well. You will need to say CASCADE if anything outside the table
75 depends on the column, for example, foreign key references or
76 views. If IF EXISTS is specified and the column does not exist, no
77 error is thrown. In this case a notice is issued instead.
78 IF EXISTS
80 Do not throw an error if the table does not exist. A notice is
81 issued in this case.
82 SET DATA TYPE
84 This form changes the type of a column of a table. Indexes and
85 simple table constraints involving the column will be automatically
86 converted to use the new column type by reparsing the originally
87 supplied expression. The optional COLLATE clause specifies a
88 collation for the new column; if omitted, the collation is the
89 default for the new column type. The optional USING clause
90 specifies how to compute the new column value from the old; if
91 omitted, the default conversion is the same as an assignment cast
92 from old data type to new. A USING clause must be provided if there
93 is no implicit or assignment cast from old to new type.
94 SET/DROP DEFAULT
96 These forms set or remove the default value for a column. The
97 default values only apply to subsequent INSERT commands; they do
98 not cause rows already in the table to change. Defaults can also be
99 created for views, in which case they are inserted into INSERT
100 statements on the view before the view's ON INSERT rule is applied.
101 SET/DROP NOT NULL
103 These forms change whether a column is marked to allow null values
104 or to reject null values. You can only use SET NOT NULL when the
105 column contains no null values.
106 SET STATISTICS
108 This form sets the per-column statistics-gathering target for
109 subsequent ANALYZE(7) operations. The target can be set in the
110 range 0 to 10000; alternatively, set it to -1 to revert to using
111 the system default statistics target (default_statistics_target).
112 For more information on the use of statistics by the PostgreSQL
113 query planner, refer to Section 14.2, “Statistics Used by the
114 Planner”, in the documentation.
115 SET ( attribute_option = value [, ... ] ), RESET ( attribute_option [,
117 ... ] )
118 This form sets or resets per-attribute options. Currently, the only
119 defined per-attribute options are n_distinct and
120 n_distinct_inherited, which override the number-of-distinct-values
121 estimates made by subsequent ANALYZE(7) operations. n_distinct
122 affects the statistics for the table itself, while
123 n_distinct_inherited affects the statistics gathered for the table
124 plus its inheritance children. When set to a positive value,
125 ANALYZE will assume that the column contains exactly the specified
126 number of distinct nonnull values. When set to a negative value,
127 which must be greater than or equal to -1, ANALYZE will assume that
128 the number of distinct nonnull values in the column is linear in
129 the size of the table; the exact count is to be computed by
130 multiplying the estimated table size by the absolute value of the
131 given number. For example, a value of -1 implies that all values in
132 the column are distinct, while a value of -0.5 implies that each
133 value appears twice on the average. This can be useful when the
134 size of the table changes over time, since the multiplication by
135 the number of rows in the table is not performed until query
136 planning time. Specify a value of 0 to revert to estimating the
137 number of distinct values normally. For more information on the use
138 of statistics by the PostgreSQL query planner, refer to Section
139 14.2, “Statistics Used by the Planner”, in the documentation.
140 SET STORAGE
142 This form sets the storage mode for a column. This controls whether
143 this column is held inline or in a secondary TOAST table, and
144 whether the data should be compressed or not. PLAIN must be used
145 for fixed-length values such as integer and is inline,
146 uncompressed. MAIN is for inline, compressible data. EXTERNAL is
147 for external, uncompressed data, and EXTENDED is for external,
148 compressed data. EXTENDED is the default for most data types that
149 support non-PLAIN storage. Use of EXTERNAL will make substring
150 operations on very large text and bytea values run faster, at the
151 penalty of increased storage space. Note that SET STORAGE doesn't
152 itself change anything in the table, it just sets the strategy to
153 be pursued during future table updates. See Section 56.2, “TOAST”,
154 in the documentation for more information.
155 ADD table_constraint [ NOT VALID ]
157 This form adds a new constraint to a table using the same syntax as
158 CREATE TABLE (CREATE_TABLE(7)), plus the option NOT VALID, which is
159 currently only allowed for foreign key and CHECK constraints. If
160 the constraint is marked NOT VALID, the potentially-lengthy initial
161 check to verify that all rows in the table satisfy the constraint
162 is skipped. The constraint will still be enforced against
163 subsequent inserts or updates (that is, they'll fail unless there
164 is a matching row in the referenced table, in the case of foreign
165 keys; and they'll fail unless the new row matches the specified
166 check constraints). But the database will not assume that the
167 constraint holds for all rows in the table, until it is validated
168 by using the VALIDATE CONSTRAINT option.
169 ADD table_constraint_using_index
171 This form adds a new PRIMARY KEY or UNIQUE constraint to a table
172 based on an existing unique index. All the columns of the index
173 will be included in the constraint.
174 The index cannot have expression columns nor be a partial index.
176 Also, it must be a b-tree index with default sort ordering. These
177 restrictions ensure that the index is equivalent to one that would
178 be built by a regular ADD PRIMARY KEY or ADD UNIQUE command.
179 If PRIMARY KEY is specified, and the index's columns are not
181 already marked NOT NULL, then this command will attempt to do ALTER
182 COLUMN SET NOT NULL against each such column. That requires a full
183 table scan to verify the column(s) contain no nulls. In all other
184 cases, this is a fast operation.
185 If a constraint name is provided then the index will be renamed to
187 match the constraint name. Otherwise the constraint will be named
188 the same as the index.
189 After this command is executed, the index is “owned” by the
191 constraint, in the same way as if the index had been built by a
192 regular ADD PRIMARY KEY or ADD UNIQUE command. In particular,
193 dropping the constraint will make the index disappear too.
194 Note
196 Adding a constraint using an existing index can be helpful in
197 situations where a new constraint needs to be added without
198 blocking table updates for a long time. To do that, create the
199 index using CREATE INDEX CONCURRENTLY, and then install it as
200 an official constraint using this syntax. See the example
201 below.
202 VALIDATE CONSTRAINT
204 This form validates a foreign key or check constraint that was
205 previously created as NOT VALID, by scanning the table to ensure
206 there are no rows for which the constraint is not satisfied.
207 Nothing happens if the constraint is already marked valid.
208 Validation can be a long process on larger tables and currently
210 requires an ACCESS EXCLUSIVE lock. The value of separating
211 validation from initial creation is that you can defer validation
212 to less busy times, or can be used to give additional time to
213 correct pre-existing errors while preventing new errors.
214 DROP CONSTRAINT [ IF EXISTS ]
216 This form drops the specified constraint on a table. If IF EXISTS
217 is specified and the constraint does not exist, no error is thrown.
218 In this case a notice is issued instead.
219 DISABLE/ENABLE [ REPLICA | ALWAYS ] TRIGGER
221 These forms configure the firing of trigger(s) belonging to the
222 table. A disabled trigger is still known to the system, but is not
223 executed when its triggering event occurs. For a deferred trigger,
224 the enable status is checked when the event occurs, not when the
225 trigger function is actually executed. One can disable or enable a
226 single trigger specified by name, or all triggers on the table, or
227 only user triggers (this option excludes internally generated
228 constraint triggers such as those that are used to implement
229 foreign key constraints or deferrable uniqueness and exclusion
230 constraints). Disabling or enabling internally generated constraint
231 triggers requires superuser privileges; it should be done with
232 caution since of course the integrity of the constraint cannot be
233 guaranteed if the triggers are not executed. The trigger firing
234 mechanism is also affected by the configuration variable
235 session_replication_role. Simply enabled triggers will fire when
236 the replication role is “origin” (the default) or “local”. Triggers
237 configured as ENABLE REPLICA will only fire if the session is in
238 “replica” mode, and triggers configured as ENABLE ALWAYS will fire
239 regardless of the current replication mode.
240 DISABLE/ENABLE [ REPLICA | ALWAYS ] RULE
242 These forms configure the firing of rewrite rules belonging to the
243 table. A disabled rule is still known to the system, but is not
244 applied during query rewriting. The semantics are as for
245 disabled/enabled triggers. This configuration is ignored for ON
246 SELECT rules, which are always applied in order to keep views
247 working even if the current session is in a non-default replication
248 role.
249 CLUSTER ON
251 This form selects the default index for future CLUSTER(7)
252 operations. It does not actually re-cluster the table.
253 SET WITHOUT CLUSTER
255 This form removes the most recently used CLUSTER(7) index
256 specification from the table. This affects future cluster
257 operations that don't specify an index.
258 SET WITH OIDS
260 This form adds an oid system column to the table (see Section 5.4,
261 “System Columns”, in the documentation). It does nothing if the
262 table already has OIDs.
263 Note that this is not equivalent to ADD COLUMN oid oid; that would
265 add a normal column that happened to be named oid, not a system
266 column.
267 SET WITHOUT OIDS
269 This form removes the oid system column from the table. This is
270 exactly equivalent to DROP COLUMN oid RESTRICT, except that it will
271 not complain if there is already no oid column.
272 SET ( storage_parameter = value [, ... ] )
274 This form changes one or more storage parameters for the table. See
275 Storage Parameters for details on the available parameters. Note
276 that the table contents will not be modified immediately by this
277 command; depending on the parameter you might need to rewrite the
278 table to get the desired effects. That can be done with VACUUM
279 FULL, CLUSTER(7) or one of the forms of ALTER TABLE that forces a
280 table rewrite.
281 Note
283 While CREATE TABLE allows OIDS to be specified in the WITH
284 (storage_parameter) syntax, ALTER TABLE does not treat OIDS as
285 a storage parameter. Instead use the SET WITH OIDS and SET
286 WITHOUT OIDS forms to change OID status.
287 RESET ( storage_parameter [, ... ] )
289 This form resets one or more storage parameters to their defaults.
290 As with SET, a table rewrite might be needed to update the table
291 entirely.
292 INHERIT parent_table
294 This form adds the target table as a new child of the specified
295 parent table. Subsequently, queries against the parent will include
296 records of the target table. To be added as a child, the target
297 table must already contain all the same columns as the parent (it
298 could have additional columns, too). The columns must have matching
299 data types, and if they have NOT NULL constraints in the parent
300 then they must also have NOT NULL constraints in the child.
301 There must also be matching child-table constraints for all CHECK
303 constraints of the parent, except those marked non-inheritable
304 (that is, created with ALTER TABLE ... ADD CONSTRAINT ... NO
305 INHERIT) in the parent, which are ignored; all child-table
306 constraints matched must not be marked non-inheritable. Currently
307 UNIQUE, PRIMARY KEY, and FOREIGN KEY constraints are not
308 considered, but this might change in the future.
309 NO INHERIT parent_table
311 This form removes the target table from the list of children of the
312 specified parent table. Queries against the parent table will no
313 longer include records drawn from the target table.
314 OF type_name
316 This form links the table to a composite type as though CREATE
317 TABLE OF had formed it. The table's list of column names and types
318 must precisely match that of the composite type; the presence of an
319 oid system column is permitted to differ. The table must not
320 inherit from any other table. These restrictions ensure that CREATE
321 TABLE OF would permit an equivalent table definition.
322 NOT OF
324 This form dissociates a typed table from its type.
325 OWNER
327 This form changes the owner of the table, sequence, or view to the
328 specified user.
329 SET TABLESPACE
331 This form changes the table's tablespace to the specified
332 tablespace and moves the data file(s) associated with the table to
333 the new tablespace. Indexes on the table, if any, are not moved;
334 but they can be moved separately with additional SET TABLESPACE
335 commands. See also CREATE TABLESPACE (CREATE_TABLESPACE(7)).
336 RENAME
338 The RENAME forms change the name of a table (or an index, sequence,
339 or view), the name of an individual column in a table, or the name
340 of a constraint of the table. There is no effect on the stored
341 data.
342 SET SCHEMA
344 This form moves the table into another schema. Associated indexes,
345 constraints, and sequences owned by table columns are moved as
346 well.
347 All the actions except RENAME and SET SCHEMA can be combined into a
349 list of multiple alterations to apply in parallel. For example, it is
350 possible to add several columns and/or alter the type of several
351 columns in a single command. This is particularly useful with large
352 tables, since only one pass over the table need be made.
353 You must own the table to use ALTER TABLE. To change the schema of a
355 table, you must also have CREATE privilege on the new schema. To add
356 the table as a new child of a parent table, you must own the parent
357 table as well. To alter the owner, you must also be a direct or
358 indirect member of the new owning role, and that role must have CREATE
359 privilege on the table's schema. (These restrictions enforce that
360 altering the owner doesn't do anything you couldn't do by dropping and
361 recreating the table. However, a superuser can alter ownership of any
362 table anyway.) To add a column or alter a column type or use the OF
363 clause, you must also have USAGE privilege on the data type.
364
366 name
367 The name (optionally schema-qualified) of an existing table to
368 alter. If ONLY is specified before the table name, only that table
369 is altered. If ONLY is not specified, the table and all its
370 descendant tables (if any) are altered. Optionally, * can be
371 specified after the table name to explicitly indicate that
372 descendant tables are included.
373 column_name
375 Name of a new or existing column.
376 new_column_name
378 New name for an existing column.
379 new_name
381 New name for the table.
382 type
384 Data type of the new column, or new data type for an existing
385 column.
386 table_constraint
388 New table constraint for the table.
389 constraint_name
391 Name of an existing constraint to drop.
392 CASCADE
394 Automatically drop objects that depend on the dropped column or
395 constraint (for example, views referencing the column).
396 RESTRICT
398 Refuse to drop the column or constraint if there are any dependent
399 objects. This is the default behavior.
400 trigger_name
402 Name of a single trigger to disable or enable.
403 ALL
405 Disable or enable all triggers belonging to the table. (This
406 requires superuser privilege if any of the triggers are internally
407 generated constraint triggers such as those that are used to
408 implement foreign key constraints or deferrable uniqueness and
409 exclusion constraints.)
410 USER
412 Disable or enable all triggers belonging to the table except for
413 internally generated constraint triggers such as those that are
414 used to implement foreign key constraints or deferrable uniqueness
415 and exclusion constraints.
416 index_name
418 The index name on which the table should be marked for clustering.
419 storage_parameter
421 The name of a table storage parameter.
422 value
424 The new value for a table storage parameter. This might be a number
425 or a word depending on the parameter.
426 parent_table
428 A parent table to associate or de-associate with this table.
429 new_owner
431 The user name of the new owner of the table.
432 new_tablespace
434 The name of the tablespace to which the table will be moved.
435 new_schema
437 The name of the schema to which the table will be moved.
438
440 The key word COLUMN is noise and can be omitted.
441 When a column is added with ADD COLUMN, all existing rows in the table
443 are initialized with the column's default value (NULL if no DEFAULT
444 clause is specified).
445 Adding a column with a non-null default or changing the type of an
447 existing column will require the entire table and indexes to be
448 rewritten. As an exception, if the USING clause does not change the
449 column contents and the old type is either binary coercible to the new
450 type or an unconstrained domain over the new type, a table rewrite is
451 not needed, but any indexes on the affected columns must still be
452 rebuilt. Adding or removing a system oid column also requires rewriting
453 the entire table. Table and/or index rebuilds may take a significant
454 amount of time for a large table; and will temporarily require as much
455 as double the disk space.
456 Adding a CHECK or NOT NULL constraint requires scanning the table to
458 verify that existing rows meet the constraint, but does not require a
459 table rewrite.
460 The main reason for providing the option to specify multiple changes in
462 a single ALTER TABLE is that multiple table scans or rewrites can
463 thereby be combined into a single pass over the table.
464 The DROP COLUMN form does not physically remove the column, but simply
466 makes it invisible to SQL operations. Subsequent insert and update
467 operations in the table will store a null value for the column. Thus,
468 dropping a column is quick but it will not immediately reduce the
469 on-disk size of your table, as the space occupied by the dropped column
470 is not reclaimed. The space will be reclaimed over time as existing
471 rows are updated. (These statements do not apply when dropping the
472 system oid column; that is done with an immediate rewrite.)
473 To force immediate reclamation of space occupied by a dropped column,
475 you can execute one of the forms of ALTER TABLE that performs a rewrite
476 of the whole table. This results in reconstructing each row with the
477 dropped column replaced by a null value.
478 The rewriting forms of ALTER TABLE are not MVCC-safe. After a table
480 rewrite, the table will appear empty to concurrent transactions, if
481 they are using a snapshot taken before the rewrite occurred. See
482 Section 13.5, “Caveats”, in the documentation for more details.
483 The USING option of SET DATA TYPE can actually specify any expression
485 involving the old values of the row; that is, it can refer to other
486 columns as well as the one being converted. This allows very general
487 conversions to be done with the SET DATA TYPE syntax. Because of this
488 flexibility, the USING expression is not applied to the column's
489 default value (if any); the result might not be a constant expression
490 as required for a default. This means that when there is no implicit or
491 assignment cast from old to new type, SET DATA TYPE might fail to
492 convert the default even though a USING clause is supplied. In such
493 cases, drop the default with DROP DEFAULT, perform the ALTER TYPE, and
494 then use SET DEFAULT to add a suitable new default. Similar
495 considerations apply to indexes and constraints involving the column.
496 If a table has any descendant tables, it is not permitted to add,
498 rename, or change the type of a column, or rename an inherited
499 constraint in the parent table without doing the same to the
500 descendants. That is, ALTER TABLE ONLY will be rejected. This ensures
501 that the descendants always have columns matching the parent.
502 A recursive DROP COLUMN operation will remove a descendant table's
504 column only if the descendant does not inherit that column from any
505 other parents and never had an independent definition of the column. A
506 nonrecursive DROP COLUMN (i.e., ALTER TABLE ONLY ... DROP COLUMN) never
507 removes any descendant columns, but instead marks them as independently
508 defined rather than inherited.
509 The TRIGGER, CLUSTER, OWNER, and TABLESPACE actions never recurse to
511 descendant tables; that is, they always act as though ONLY were
512 specified. Adding a constraint recurses only for CHECK constraints that
513 are not marked NO INHERIT.
514 Changing any part of a system catalog table is not permitted.
516 Refer to CREATE TABLE (CREATE_TABLE(7)) for a further description of
518 valid parameters. Chapter 5, Data Definition, in the documentation has
519 further information on inheritance.
520
522 To add a column of type varchar to a table:
523 ALTER TABLE distributors ADD COLUMN address varchar(30);
525 To drop a column from a table:
527 ALTER TABLE distributors DROP COLUMN address RESTRICT;
529 To change the types of two existing columns in one operation:
531 ALTER TABLE distributors
533 ALTER COLUMN address TYPE varchar(80),
534 ALTER COLUMN name TYPE varchar(100);
535 To change an integer column containing UNIX timestamps to timestamp
537 with time zone via a USING clause:
538 ALTER TABLE foo
540 ALTER COLUMN foo_timestamp SET DATA TYPE timestamp with time zone
541 USING
542 timestamp with time zone 'epoch' + foo_timestamp * interval '1 second';
543 The same, when the column has a default expression that won't
545 automatically cast to the new data type:
546 ALTER TABLE foo
548 ALTER COLUMN foo_timestamp DROP DEFAULT,
549 ALTER COLUMN foo_timestamp TYPE timestamp with time zone
550 USING
551 timestamp with time zone 'epoch' + foo_timestamp * interval '1 second',
552 ALTER COLUMN foo_timestamp SET DEFAULT now();
553 To rename an existing column:
555 ALTER TABLE distributors RENAME COLUMN address TO city;
557 To rename an existing table:
559 ALTER TABLE distributors RENAME TO suppliers;
561 To rename an existing constraint:
563 ALTER TABLE distributors RENAME CONSTRAINT zipchk TO zip_check;
565 To add a not-null constraint to a column:
567 ALTER TABLE distributors ALTER COLUMN street SET NOT NULL;
569 To remove a not-null constraint from a column:
571 ALTER TABLE distributors ALTER COLUMN street DROP NOT NULL;
573 To add a check constraint to a table and all its children:
575 ALTER TABLE distributors ADD CONSTRAINT zipchk CHECK (char_length(zipcode) = 5);
577 To add a check constraint only to a table and not to its children:
579 ALTER TABLE distributors ADD CONSTRAINT zipchk CHECK (char_length(zipcode) = 5) NO INHERIT;
581 (The check constraint will not be inherited by future children,
583 either.)
584 To remove a check constraint from a table and all its children:
586 ALTER TABLE distributors DROP CONSTRAINT zipchk;
588 To remove a check constraint from one table only:
590 ALTER TABLE ONLY distributors DROP CONSTRAINT zipchk;
592 (The check constraint remains in place for any child tables.)
594 To add a foreign key constraint to a table:
596 ALTER TABLE distributors ADD CONSTRAINT distfk FOREIGN KEY (address) REFERENCES addresses (address);
598 To add a (multicolumn) unique constraint to a table:
600 ALTER TABLE distributors ADD CONSTRAINT dist_id_zipcode_key UNIQUE (dist_id, zipcode);
602 To add an automatically named primary key constraint to a table, noting
604 that a table can only ever have one primary key:
605 ALTER TABLE distributors ADD PRIMARY KEY (dist_id);
607 To move a table to a different tablespace:
609 ALTER TABLE distributors SET TABLESPACE fasttablespace;
611 To move a table to a different schema:
613 ALTER TABLE myschema.distributors SET SCHEMA yourschema;
615 To recreate a primary key constraint, without blocking updates while
617 the index is rebuilt:
618 CREATE UNIQUE INDEX CONCURRENTLY dist_id_temp_idx ON distributors (dist_id);
620 ALTER TABLE distributors DROP CONSTRAINT distributors_pkey,
621 ADD CONSTRAINT distributors_pkey PRIMARY KEY USING INDEX dist_id_temp_idx;
622
624 The forms ADD (without USING INDEX), DROP, SET DEFAULT, and SET DATA
625 TYPE (without USING) conform with the SQL standard. The other forms are
626 PostgreSQL extensions of the SQL standard. Also, the ability to specify
627 more than one manipulation in a single ALTER TABLE command is an
628 extension.
629 ALTER TABLE DROP COLUMN can be used to drop the only column of a table,
631 leaving a zero-column table. This is an extension of SQL, which
632 disallows zero-column tables.
633
635 CREATE TABLE (CREATE_TABLE(7))
636PostgreSQL 9.2.24 2017-11-06 ALTER TABLE(7)