如何使用psql命令在PostgreSQL中执行Oracle的DESCRIBE TABLE?


当前回答

如果您想从查询而不是psql获取它,可以查询目录模式。下面是一个复杂的查询,它可以做到这一点:

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
;

它非常复杂,但它确实向您展示了PostgreSQL系统目录的强大和灵活性,并将帮助您掌握pg_catalog;-)。请确保更改查询中的%s。第一个是Schema,第二个是表名。

其他回答

In postgres\d用于描述表结构。

例如\d schema_name.table_name

该命令将为您提供表的基本信息,如列、类型和修饰符。

如果您想了解更多有关表格使用的信息

\d+ schema_name.table_name

这将为您提供额外的信息,如存储、统计目标和描述

当表名以大写字母开头时,应将表名放在引号中。

示例:\d“用户”

您可以使用psql斜杠命令执行此操作:

 \d myTable describe table

它也适用于其他对象:

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

来源:faqs.org

这应该是解决方案:

SELECT * FROM information_schema.columns
WHERE table_schema = 'your_schema'
   AND table_name   = 'your_table'

除了PostgreSQL方式(\d“something”或\dt“table”或\ds“sequence”等)

SQL标准方式,如下所示:

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

它受到许多db引擎的支持。