DESCRIBE

Function

Views the structure of a specified table.

Precautions

You need to specify the schema corresponding to the temporary table for query.
All participating columns of a composite primary key index are displayed as PRI in the Key column.
All participating columns of the composite unique index are displayed as UNI in the Key column.
If a column is involved in the creation of multiple indexes, the Key column is displayed based on the first index created in the column.
The generated column is displayed in Default.
Table synonyms are not supported.

Syntax

{DESCRIBE | DESC} tbl_name

Parameter Description

{DESCRIBE | DESC}

 The effect of using DESCRIBE is equivalent to that of using DESCRIBE.

tbl_name

 Table name. You can specify a table name or **schema\_name.table\_name**.

Examples

--Create a test table.
MogDB=# CREATE TABLE test2
MogDB-# (
MogDB(# id int PRIMARY KEY
MogDB(# );
NOTICE:  CREATE TABLE / PRIMARY KEY will create implicit index "test2_pkey" for table "test2"
CREATE TABLE
MogDB=# create table test
MogDB-# (
MogDB(# a SERIAL,
MogDB(# b varchar(10),
MogDB(# c varchar(10),
MogDB(# d varchar(10),
MogDB(# e varchar(10),
MogDB(# f varchar(10),
MogDB(# g varchar(10) DEFAULT 'g',
MogDB(# h varchar(10) NOT NULL,
MogDB(# i int DEFAULT 0,
MogDB(# j int DEFAULT 0,
MogDB(# k int GENERATED ALWAYS AS (i + j) STORED,
MogDB(# l int DEFAULT 0,
MogDB(# m int CHECK (m < 50),
MogDB(# PRIMARY KEY (a, b),
MogDB(# FOREIGN KEY(l) REFERENCES test2(id)
MogDB(# );
NOTICE:  CREATE TABLE will create implicit sequence "test_a_seq" for serial column "test.a"
NOTICE:  CREATE TABLE / PRIMARY KEY will create implicit index "test_pkey" for table "test"
CREATE TABLE
MogDB=# CREATE UNIQUE INDEX idx_c on test (c);
CREATE INDEX
MogDB=# CREATE UNIQUE INDEX idx_d_e on test (d, e);
CREATE INDEX
MogDB=# CREATE INDEX idx_f on test (f);
CREATE INDEX

--View the structure of the test table.
MogDB=# desc test;
 Field |         Type          | Null | Key |             Default             | Extra
-------+-----------------------+------+-----+---------------------------------+-------
 a     | integer               | NO   | PRI | nextval('test_a_seq'::regclass) |
 b     | character varying(10) | NO   | PRI | NULL                            |
 c     | character varying(10) | YES  | UNI | NULL                            |
 d     | character varying(10) | YES  | UNI | NULL                            |
 e     | character varying(10) | YES  | UNI | NULL                            |
 f     | character varying(10) | YES  | MUL | NULL                            |
 g     | character varying(10) | YES  |     | 'g'::character varying          |
 h     | character varying(10) | NO   |     | NULL                            |
 i     | integer               | YES  |     | 0                               |
 j     | integer               | YES  |     | 0                               |
 k     | integer               | YES  |     | (i + j)                         |
 l     | integer               | YES  | MUL | 0                               |
 m     | integer               | YES  |     | NULL                            |
(13 rows)

MogDB=# desc public.test;
 Field |         Type          | Null | Key |             Default             | Extra
-------+-----------------------+------+-----+---------------------------------+-------
 a     | integer               | NO   | PRI | nextval('test_a_seq'::regclass) |
 b     | character varying(10) | NO   | PRI | NULL                            |
 c     | character varying(10) | YES  | UNI | NULL                            |
 d     | character varying(10) | YES  | UNI | NULL                            |
 e     | character varying(10) | YES  | UNI | NULL                            |
 f     | character varying(10) | YES  | MUL | NULL                            |
 g     | character varying(10) | YES  |     | 'g'::character varying          |
 h     | character varying(10) | NO   |     | NULL                            |
 i     | integer               | YES  |     | 0                               |
 j     | integer               | YES  |     | 0                               |
 k     | integer               | YES  |     | (i + j)                         |
 l     | integer               | YES  | MUL | 0                               |
 m     | integer               | YES  |     | NULL                            |
(13 rows)

MogDB=# describe public.test;
 Field |         Type          | Null | Key |             Default             | Extra
-------+-----------------------+------+-----+---------------------------------+-------
 a     | integer               | NO   | PRI | nextval('test_a_seq'::regclass) |
 b     | character varying(10) | NO   | PRI | NULL                            |
 c     | character varying(10) | YES  | UNI | NULL                            |
 d     | character varying(10) | YES  | UNI | NULL                            |
 e     | character varying(10) | YES  | UNI | NULL                            |
 f     | character varying(10) | YES  | MUL | NULL                            |
 g     | character varying(10) | YES  |     | 'g'::character varying          |
 h     | character varying(10) | NO   |     | NULL                            |
 i     | integer               | YES  |     | 0                               |
 j     | integer               | YES  |     | 0                               |
 k     | integer               | YES  |     | (i + j)                         |
 l     | integer               | YES  | MUL | 0                               |
 m     | integer               | YES  |     | NULL                            |
(13 rows)

Helpful Links

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