Hive学习笔记 --- Hive外部表和内部表的关系

• 1.默认情况下是内部表（MANAGED_TABLE）；

• 2.外部表（External Table）创建的时候需要加上External关键字，并指定位置存储位置；

• 3.删除内部表会直接删除元数据（METADATA）以及存储数据；删除外部表仅仅会删除元数据，HDFS上的文件并不会删除；

• 4.内部表由数据由Hive自由管理，外部表数据由HDFS管理；

• 5.对内部表的修改直接同步给元数据，而对外部表的表结构和分区进行修改，则需要修复（MSCK REPAIR TABLE Table_NAME）;

如下是Hive-WIKI中的关于外部表的描述：

A table created without the EXTERNAL clause is called a managed table because Hive manages its data.

Managed and External Tables

By default Hive creates managed tables, where files, metadata and statistics are managed by internal Hive processes. A managed table is stored under the hive.metastore.warehouse.dir path property, by default in a folder path similar to /apps/hive/warehouse/databasename.db/tablename/. The default location can be overridden by the location property during table creation. If a managed table or partition is dropped, the data and metadata associated with th