Writable External table demonstration

This section describes how to extract data from the data warehouse to a flat file. The data warehouse table is EMP and the destination file is emp.txt. Gtlions = # select * from emp; empno | ename | job | mgr | hiredate | sal | comm | deptno ------- + -------- + ----------- + ------ + ------------ + ---------- + -------- 7499 | ALLEN | SALESMAN | 7698 | 1600.00 | 300.00 | 30 7521 | WARD | SALESMAN | 7698 | 1981-02-22 | 1250.00 | 500.00 | 30 7698 | BLAKE | MANAGER | 7839 | 2850.00 | 30 7782 | CLARK | MANAGER | 7839 | 1981-06 -09 | 2450.00 | 10 7788 | SCOTT | ANALYST | 7566 | 1982-12-09 | 3000.00 | 20 7844 | TURNER | SALESMAN | 7698 | 1981-09-08 | 1500.00 | 0.00 | 30 7876 | ADAMS | CLERK | 7788 | 1983-01-12 | 1100.00 | 20 7900 | JAMES | CLERK | 7698 | 1981-12-03 | 950.00 | 30 7902 | FORD | ANALYST | 7566 | 1981-12-03 | 3000.00 | 20 7934 | MILLER | CLERK | 7782 | 1982-01-23 | 1300.00 | 10 8200 | Sun Jian | sales | 81 80 | 1934-11-30 | 1000.00 | 70 8220 | sun ce | finance | 8180 | 1937-12-03 | 4100.00 | 345.00 | 50 8240 | Zhuge Jin | R & D | 8180 | 1940-01-07 | 1000.00 | 80 7369 | SMITH | CLERK | 7902 | 1980-12-17 | 800.00 | 20 7566 | JONES | MANAGER | 7839 | 1981-04-02 | 2975.00 | 20 7654 | MARTIN | SALESMAN | 7698 | 1981-09-28 | 1250.00 | 1400.00 | 30 7839 | KING | PRESIDENT | 1981-11-17 | 5000.00 | 10 8000 | leaf | Boss | 99999.00 | 99999.00 | 90 8010 | Liu Bei | manager | 8000 | 21000.00 | 200.00 | 8020 | 60 8010 | Zhang Fei | sales | 41000.00 | 300.00 | 70 8040 | Zhao Yun | finance | 8010 | 61000.00 | 50 8060 | Guan Yu | R & D | 8010 | 1913-04-10 | 81000.00 | 80 8080 | Zhuge Liang | Xianzhi | 8010 | 10100.00 | | 60 8100 | Cao | manager | 8000 | 12100.00 | 389.00 | 60 8120 | Cao Yu | sales | 8100 | 14100.00 | 70 8140 | Cao Zhi | finance | 8100 | 16100.00 | 700.00 | 8160 | 50 8100 | Cao ang | R & D | 18100.00 | 8180 | 80 | | Sun Quan | manager | 8000 | 1931-10-28 | 20100.00 | 409.00 | 60 (28 rows) gtlions = # create writable external table emp_exp (like emp) location ('gpfdist: // o564gtser1: 8080/emp_exp.txt ') format 'text'; NOTICE: table doesn't have 'distributed by 'clause, defau Lting to distribution columns from LIKE tableCREATE EXTERNAL TABLEgtlions = # insert into emp_exp select * from emp; INSERT 0 28 gtlions = # select * from emp_exp; ERROR: it is not possible to read from a WRITABLE external table. HINT: Create the table as READABLE instead [gpadmin @ o564gtser1 gpfdist] $ cat emp_exp.txt 7499 allen salesman 7698 1981-02-20 1600.00 300.00 307521 ward salesman 7698 1981-02-22 12 50.00 500.00 307698 blake manager 7839 1981-05-01 2850.00 \ N 307782 clark manager 7839 1981-06-09 2450.00 \ N 107788 scott analyst 7566 1982-12-09 3000.00 \ N 207844 turner salesman 7698 1981-09-08 1500.00 0.00 307876 adams clerk 7788 1983-01-12 1100.00 \ N 207900 james clerk 7698 1981-12-03 950.00 \ N 307902 ford analyst 7566 1981-12-03 3000.00 \ N 207934 miller clerk 7782 1982-01-23 1300.00 \ N 108200 Sun Jian sales 8180 1934-11-30 1000.00 \ N 708220 sun ce finance 8180 1937-12-03 4100.00 345.00 Zhuge Jin R & D 508240 1940-01-07 8180 \ N 1000.00 smith clerk 807369 1980-12-17 7902 \ N 800.00 jones manager 207566 1981-04-02 7839 \ N 2975.00 martin salesman 7698 1981-09-28 1250.00 1400.00 307839 king president \ N 1981-11-17 5000.00 \ N 108000 leaf boss \ N 1984-01-18 99999.00 99999.00 908010 Liu Bei manager 8000 21000.00 200. 00 608020 Zhang Fei sales 8010 1907-02-04 41000.00 300.00 708040 Zhao yunying 8010 1910-03-07 61000.00 \ N 508060 Guan Yu R & D 8010 1913-04-10 81000.00 \ N 808080 Zhuge Liang xiangren 8010 1916-05-13 10100.00 \ N 608100 Cao manager 8000 19-06-16 12100.00 389.00 608120 cao Yu sales 8100 1922-07-19 14100.00 \ N 708140 Cao Zhi finance 8100 1925-08-22 16100.00 700.00 508160 Cao ang R & D 8100 1928-09-25 18100.00 \ N 808180 Sun Quan manager 8000 1931-10-28 20100.00 409.00 60 so as to unload data To the flat file, note that the writable operation is not allowed except insert. -EOF-