如何在PostgreSQL中列出表的所有约束？

如何在PostgreSQL中列出表的所有约束（主键，检查，唯一互斥，..）？

可以通过检索约束pg_catalog.pg_constraint。

SELECT con.*
       FROM pg_catalog.pg_constraint con
            INNER JOIN pg_catalog.pg_class rel
                       ON rel.oid = con.conrelid
            INNER JOIN pg_catalog.pg_namespace nsp
                       ON nsp.oid = connamespace
       WHERE nsp.nspname = '<schema name>'
             AND rel.relname = '<table name>';

用<schema name>您的模式<table name>名称和表名称替换。

在psql命令行中，此信息位于通过\d+命令获得的表格中。d+还告知NOT NULL约束，pg_catalog.pg_constraint表中未包含某些内容。一个例子：

# \d+ observations.stream   
                                                  Table "observations.stream"
 Column |       Type        | Collation | Nullable | Default | Storage  | Stats target |                 Description                 
--------+-------------------+-----------+----------+---------+----------+--------------+---------------------------------------------
 id     | integer           |           | not null |         | plain    |              | 
 name   | character varying |           | not null |         | extended |              | This should be a table in the import schema
 min_id | integer           |           | not null |         | plain    |              | 
 about  | character varying |           | not null |         | extended |              | 
Indexes:
    "stream_pkey" PRIMARY KEY, btree (id)
    "stream_name_key" UNIQUE CONSTRAINT, btree (name)
Check constraints:
    "stream_id_check" CHECK (id > 0)
Referenced by:
    TABLE "profile" CONSTRAINT "profile_id_stream_fkey" FOREIGN KEY (id_stream) REFERENCES stream(id)

需要注意的是，您不能通过这种方式获得所有约束的名称。