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Oracle 9i轻松取得建表和索引的DDL语句

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Jun 07, 2016 pm 06:04 PM

Oracle 9i轻松取得建表和索引的DDL语句

正在看的ORACLE教程是:Oracle 9i轻松取得建表和索引的DDL语句。我们都知道在9i之前，要想获得建表和索引的语句是一件很麻烦的事。我们通常的做法都是通过export with rows=no来得到，但它的输出因为格式的问题并不能直接拿来用。而另一种方法就是写复杂的脚本来查询数据字典，但这对于一稍微复杂的对象，如IOT和嵌套表等，还是无法查到。

　　从数据字典中获得DDL语句是经常要用的，特别是在系统升级/重建的时候。在Oracle 9i中，我们可以直接通过执行dbms_metadata从数据字典中查处DDL语句。使用这个功能强大的工具，我们可以获得单个对象或整个SCHEMA的DDL语句。最好不过的是因为它使用起来很简单。

　　1、获得单个表和索引DDL语句的方法：

　　下面是输出。我们只要把建表/索引语句取出来在后面加个分号就可以直接运行了。

　　2、获得整个SCHEMA DDL语句的方法：

　　需要注意的是，当我们的表中有外健（参照约束）时，我们需要判别参照表之间的顺序，确保重建时按照合理的顺序进行。你可以通过查询dba_constraints and dba_cons_columns来确定各表之间的顺序，不再详述。

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