Sqoop 面试题与答案

问题 11. Explain the purpose of the --map-column-java option in Sqoop.

The --map-column-java option allows you to specify how the columns from the database table should be mapped to Java types during import.

Example:

sqoop import --connect jdbc:mysql://localhost:3306/db --table mytable --map-column-java id=String,value=Double

问题 12. What is the difference between the free-form query import and table-based import in Sqoop?

In free-form query import, you can specify a SQL query to extract data, while in table-based import, you directly import an entire table.

问题 13. Explain the purpose of the --direct-split-size option in Sqoop.

The --direct-split-size option is used to specify the number of bytes per split when using direct mode for imports and exports.

Example:

sqoop import --connect jdbc:mysql://localhost:3306/db --table mytable --direct --direct-split-size 1000000

问题 14. How can you perform a full load import in Sqoop?

A full load import in Sqoop can be done by using the --m (or --num-mappers) option with a value of 1 to import the data using a single mapper.

Example:

sqoop import --connect jdbc:mysql://localhost:3306/db --table mytable --m 1

问题 15. Explain the purpose of the --merge-key option in Sqoop.

The --merge-key option is used during the Sqoop merge operation to specify the columns used for identifying rows to merge.