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


当前回答

除了已经找到的命令行\d+<table_name>之外,还可以使用info_schema.columns使用信息模式查找列数据

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

其他回答

1) 使用psql的PostgreSQL描述表

在psql命令行工具中,使用\d table_name或\d+table_name查找表的列信息

2) PostgreSQL使用information_schema描述表

SELECT语句查询information_schema数据库中列表的column_name、数据类型、字符最大长度;

选择列名称、数据类型、字符最大长度来自INFORMATION_SCHEMA.COLUMNS,其中table_name=“tablename”;

有关详细信息https://www.postgresqltutorial.com/postgresql-describe-table/

尝试以下操作(在psql命令行工具中):

\d+ tablename

有关更多信息,请参阅手册。

除了已经找到的命令行\d+<table_name>之外,还可以使用info_schema.columns使用信息模式查找列数据

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

这应该是解决方案:

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

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。