Common Concepts

Client
Users can access the server from the client through the Java API and Thrift API to perform Hive-related operations.
HQL
Similar to SQL
HCatalog
HCatalog is a table information management layer created based on Hive metadata and absorbs DDL commands of Hive. HCatalog provides read/write interfaces for MapReduce and provides Hive command line interfaces (CLIs) for defining data and querying metadata. Hive and MapReduce development personnel can share metadata based on the HCatalog component of MRS, preventing intermediate conversion and adjustment and improving the data processing efficiency.
WebHCat
WebHCat running users use Rest APIs to perform operations, such as running Hive DDL commands, submitting MapReduce tasks, and querying MapReduce task execution results.