Hive Table Type Mapping to JDBC Table Type

Hive Table Type Mapping to JDBC Table Type

• Create external table

For hive, if you want to create an external table, please use the following HQL:

CREATE EXTERNAL TABLE marvin_ext_table1(id INT, name STRING, age INT) ROW FORMAT DELIMITED FIELDS TERMINATED BY ',' STORED AS TEXTFILE LOCATION ‘/user/marvin/externaTable1′;

Hive will create a table named marvin_ext_table1 which points to an existing file(data) externaTable1 in the HDFS path /user/marvin/. The contents of file named externaTable1 are as follows:

001,Marvin,27
090,Jack,22
111,Lucy,32

• JDBC for Hive to Get Tables

The following is a map to JDBC table types from Hive table types:

Hive Table Type         JDBC Table Type
    MANAGED_TABLE     ->        'TABLE'
    VIRTUAL_VIEW      ->        'VIEW'
    EXTERNAL_TABLE    ->     'EXTERNAL TABLE'

For hive there are some table types in the enum of TableType as follows:

public enum TableType {
  MANAGED_TABLE, EXTERNAL_TABLE, VIRTUAL_VIEW, INDEX_TABLE
}

 If you want to get the JDBC types of hive, you could invoke the method in HiveDatabaseMetaData:

/**
   * Translate hive table types into jdbc table types.
   * @param hivetabletype
   * @return
   */
  public static String toJdbcTableType(String hivetabletype) {
    if (hivetabletype==null) {
      return null;
    } else if (hivetabletype.equals(TableType.MANAGED_TABLE.toString())) {
      return "TABLE";
    } else if (hivetabletype.equals(TableType.VIRTUAL_VIEW.toString())) {
      return "VIEW";
    } else if (hivetabletype.equals(TableType.EXTERNAL_TABLE.toString())) {
      return "EXTERNAL TABLE";
    } else {
      return hivetabletype;
    }
  }

转载于:https://my.oschina.net/javachina/blog/108302