Question

我需要编写代码来学习有关几个数据库的一些信息。我们的客户将执行代码，因此我无法“在线”调整它。数据库将是Oracle（9,10,11），DB2，AS400 DB2，Informix和MS SQL（2000和2008）。我编写了Oracle所需的代码，但我对其他数据库一无所知。你能帮我复制一下其他数据库吗？非常感谢！

1

select owner, count(*) -- number of tables in schemes
  from all_tables
 where owner not in ('SYS', 'SYSTEM', 'SYSMAN') and temporary = 'N'
 group by owner

2

 select atc.owner, atc.data_type, count(*) --number of tables by schemes and datatypes
      from all_tab_columns atc
     inner join all_tables t
        on t.OWNER = atc.OWNER
       and t.TABLE_NAME = atc.TABLE_NAME
     where atc.owner not in ('SYS', 'SYSTEM', 'SYSMAN')
       and t.temporary = 'N'
     group by atc.owner, atc.data_type

3

select atcom.owner, count(*) --number of comments by schemes
  from all_tab_comments atcom
   inner join all_tables t
    on t.OWNER = atcom.OWNER
   and t.TABLE_NAME = atcom.TABLE_NAME
 where atcom.comments is not null
 and atcom.owner not in ('SYS', 'SYSTEM', 'SYSMAN')
 group by atcom.owner

4

 select owner, constraint_type, count(*) --number of constraints by schemes and types
      from all_constraints ac
     where status = 'ENABLED' and owner not in ('SYS', 'SYSTEM', 'SYSMAN')
     group by owner, constraint_type

Answer 1

你有一些选择。

使用ODBC或JDBC等技术，您可以使用其API来阅读此类信息。如果您使用JDBC，则DatabaseMetaData： http://docs.oracle.com/javase/8/docs/api/java/sql/DatabaseMetaData.html
您可以通过SQL查询数据库使用的架构信息。我在我的工具中使用这样的查询，将数据库模式转储到文本文件：https://code.activestate.com/recipes/576621-dump-informix-schema-to-text/?in=user-186902。对于Informix，表名的qyerying如下所示：
```
SELECT tabname
FROM systables
WHERE tabtype='T'
AND tabid >= 100
AND tabname[1] <> '_'
ORDER BY tabname
```

表列表（在DB2，SQL Server，Informix和Oracle中）

1 个答案: