Creates a readable external table, ext_expenses, from all files with the txt extension using the gpfdists protocol. The column delimiter is a pipe ( | ) and NULL (' ') is a space. For information about the location of security certificates, see gpfdists:// 协议.

1. Run gpfdist with the --ssl option.
2. Run the following command.

   =# CREATE EXTERNAL TABLE ext_expenses ( name text, 
      date date,  amount float4, category text, desc1 text ) 
      LOCATION ('gpfdists://etlhost-1:8081/*.txt', 
                'gpfdists://etlhost-2:8082/*.txt')
      FORMAT 'TEXT' ( DELIMITER '|' NULL ' ') ;