select
(select relname from pg_class where oid=a.attrelid) relname ,
(select relname||'--'||(select description from pg_description where objoid=oid and objsubid=0) as comment from pg_class where oid=a.attrelid) as table_name,
a.attname as column_name,
format_type(a.atttypid,a.atttypmod) as data_type,
(case when atttypmod-4>0 then atttypmod-4 else 0 end)data_length,
(case when (select count(*) from pg_constraint where conrelid = a.attrelid and conkey[1]=attnum and contype='p')>0 then 'Y' else 'N' end) as 主键约束,
(case when (select count(*) from pg_constraint where conrelid = a.attrelid and conkey[1]=attnum and contype='u')>0 then 'Y' else 'N' end) as 唯一约束,
(case when (select count(*) from pg_constraint where conrelid = a.attrelid and conkey[1]=attnum and contype='f')>0 then 'Y' else 'N' end) as 外键约束,
(case when a.attnotnull=true then 'Y' else 'N' end) as nullable,
col_description(a.attrelid,a.attnum) as comment
from pg_attribute a
where attstattarget=-1 and attrelid in (select oid from pg_class where relname in(select relname from pg_class where relkind ='r' and relname not like 'pg_%' ))
order by relname,a.attnum;
