You specify a custom data format in the FORMAT clause of CREATE EXTERNAL TABLE.

FORMAT 'CUSTOM' (formatter=format_function, key1=val1,...keyn=valn)

Where the 'CUSTOM' keyword indicates that the data has a custom format and formatter specifies the function to use to format the data, followed by comma-separated parameters to the formatter function.

Greenplum Database provides functions for formatting fixed-width data, but you must author the formatter functions for variable-width data. The steps are as follows.

1. Author and compile input and output functions as a shared library.
2. Specify the shared library function with CREATE FUNCTION in Greenplum Database.

3. Use the formatter parameter of CREATE EXTERNAL TABLE’s FORMAT clause to call the function.

4. Importing and Exporting Fixed Width Data

5. Examples: Read Fixed-Width Data

Parent topic: Loading and Writing Non-HDFS Custom Data