Apache Sqoop is a tool designed for efficiently transferring data betweeen structured, semi-structured and unstructured data sources. Relational databases are examples of structured data sources with well defined schema for the data they store. Cassandra, Hbase are examples of semi-structured data sources and HDFS is an example of unstructured data source that Sqoop can support.Apache Sqoop 是设计来用于在结构化、半结构化和非结构化数据源之间有效转换数据的工具之一。关系型数据库存储了良好定义的结构化的模型数据。Cassandra, Hbase 存储的是半结构化的数据。HDFS 存储的是非结构化的数据。这些都是Sqoop支持数据转换的数据库。