需求:构建简单的测试用例,完成演示Vertica导出数据的功能。
  测试用例:导出test业务用户t_jingyu表中的数据。
  一、初始化测试环境
  业务用户test下创建t_jingyu测试表,并初始化一些数据.
  参考《Vertica 业务用户指定资源池加载数据》构建初始化测试环境。
  二、导出数据
  2.1 vsql命令说明帮助
[dbadmin@vertica1 ~]$ vsql --help
This is vsql, the Vertica Analytic Database interactive terminal.
Usage:
vsql [OPTIONS]... [DBNAME [USERNAME]]
General options:
-d DBNAME       specify database name to connect to (default: "dbadmin")
-c COMMAND      run only single command (SQL or internal) and exit
-f FILENAME     execute commands from file, then exit
-l              list available databases, then exit
-v NAME=VALUE   set vsql variable NAME to VALUE
-X              do not read startup file (~/.vsqlrc)
--help          show this help, then exit
--version       output version information, then exit
Input and output options:
-a              echo all input from script
-e              echo commands sent to server
-E              display queries that internal commands generate
-q              run quietly (no messages, only query output)
-o FILENAME     send query results to file (or |pipe)
-n              disable enhanced command line editing (readline)
-s              single-step mode (confirm each query)
-S              single-line mode (end of line terminates SQL command)
Output format options:
-A              unaligned table output mode (-P format=unaligned)
-b              beep on command completion
-H              HTML table output mode (-P format=html)
-t              print rows only (-P tuples_only)
-T TEXT         set HTML table tag attributes (width, border) (-P tableattr=)
-x              turn on expanded table output (-P expanded)
-P VAR[=ARG]    set printing option VAR to ARG (see pset command)
-F STRING       set field separator for unaligned output (default: "|") (-P fieldsep=)
-R STRING       set record separator (default: newline) (-P recordsep=)
Connection options:
-B SERVER:PORT  set connection backup server/port (default: not set)
-C              enable connection load balancing (default: not enabled)
-h HOSTNAME     database server host or socket directory (default: "local socket")
-p PORT         database server port (default: "5433")
-U NAME         database user name (default: "dbadmin")
-W              prompt for password (should happen automatically)
-w PASSWORD     database user's password
-k KRB SERVICE  Kerberos service name (default: "vertica")
-K KRB HOST     Kerberos host name
For more information, type "?" (for vsql commands)
from within vsql, or consult the vsql section in
the Vertica Analytic Database documentation.
  2.2 导出全表数据
  根据vsql参数说明,确定本次导出表数据的命令:
  vsql -Utest -wtestpwd -At -F'|' -c "select * from t_jingyu" -o /tmp/t_jingyu_expdata.dat
  终实现将test用户下t_jingyu的数据导出到文件/tmp/t_jingyu_expdata.dat中。
  2.3 导出符合指定条件的表数据
  可以指定where条件,只导出符合条件的数据,例如:
  vsql -Utest -wtestpwd -At -F'|' -c "select * from t_jingyu where col1=1" -o /tmp/t_jingyu_expdata_col1.dat
  这样只导出col1=1的t_jingyu表中数据到文件/tmp/t_jingyu_expdata_col1.dat中。
  三、验证
  查看表数据的导出文件/tmp/t_jingyu_expdata.dat内容:
  [dbadmin@vertica1 tmp]$ more /tmp/t_jingyu_expdata.dat
  4|martin|2014-06-20 00:00:00
  1|jingyu|2014-06-19 00:00:00
  5|靖宇|2014-06-19 00:00:00
  3|alfred|2014-05-20 00:00:00
  2|xiaobei|2014-06-20 00:00:00
  查看表数据的导出文件/tmp/t_jingyu_expdata_col1.dat内容:
  [dbadmin@vertica1 tmp]$ more /tmp/t_jingyu_expdata_col1.dat
  1|jingyu|2014-06-19 00:00:00