psql - PostgreSQL "DESCRIBE TABLE"

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Top 5 Answer for psql - PostgreSQL "DESCRIBE TABLE"

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Try this (in the psql command-line tool):

\d+ tablename 

See the manual for more info.

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In addition to the PostgreSQL way (\d 'something' or \dt 'table' or \ds 'sequence' and so on)

The SQL standard way, as shown here:

select column_name, data_type, character_maximum_length, column_default, is_nullable from INFORMATION_SCHEMA.COLUMNS where table_name = '<name of table>'; 

It's supported by many db engines.

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If you want to obtain it from query instead of psql, you can query the catalog schema. Here's a complex query that does that:

SELECT       f.attnum AS number,       f.attname AS name,       f.attnum,       f.attnotnull AS notnull,       pg_catalog.format_type(f.atttypid,f.atttypmod) AS type,       CASE           WHEN p.contype = 'p' THEN 't'           ELSE 'f'       END AS primarykey,       CASE           WHEN p.contype = 'u' THEN 't'           ELSE 'f'     END AS uniquekey,     CASE         WHEN p.contype = 'f' THEN g.relname     END AS foreignkey,     CASE         WHEN p.contype = 'f' THEN p.confkey     END AS foreignkey_fieldnum,     CASE         WHEN p.contype = 'f' THEN g.relname     END AS foreignkey,     CASE         WHEN p.contype = 'f' THEN p.conkey     END AS foreignkey_connnum,     CASE         WHEN f.atthasdef = 't' THEN d.adsrc     END AS default FROM pg_attribute f       JOIN pg_class c ON c.oid = f.attrelid       JOIN pg_type t ON t.oid = f.atttypid       LEFT JOIN pg_attrdef d ON d.adrelid = c.oid AND d.adnum = f.attnum       LEFT JOIN pg_namespace n ON n.oid = c.relnamespace       LEFT JOIN pg_constraint p ON p.conrelid = c.oid AND f.attnum = ANY (p.conkey)       LEFT JOIN pg_class AS g ON p.confrelid = g.oid   WHERE c.relkind = 'r'::char       AND n.nspname = '%s'  -- Replace with Schema name       AND c.relname = '%s'  -- Replace with table name       AND f.attnum > 0 ORDER BY number ; 

It's pretty complex but it does show you the power and flexibility of the PostgreSQL system catalog and should get you on your way to pg_catalog mastery ;-). Be sure to change out the %s's in the query. The first is Schema and the second is the table name.

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You can do that with a psql slash command:

 \d myTable describe table 

It also works for other objects:

 \d myView describe view  \d myIndex describe index  \d mySequence describe sequence 


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The psql equivalent of DESCRIBE TABLE is \d table.

See the psql portion of the PostgreSQL manual for more details.

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