1 GBase 8s数据类型

2 GBase 8s内置数据类型

3 数据类型演示

—3.1 创建员工信息表

database mydb;

create table t_employee(
    f_employeeid serial,
    f_employeename varchar(50),
    f_age int,
    f_weight float,
    f_height decimal(18,6),
    f_salary money,
    f_joindate date,
    f_inputdate datetime year to second);

—3.2 验证serial数据类型

插入三条记录，只输入员工姓名

insert into t_employee(f_employeename) values('Tom');
insert into t_employee(f_employeename) values('Jack');
insert into t_employee(f_employeename) values('Mary');

查询员工ID和员工姓名

> select f_employeeid, f_employeename from t_employee;

f_employeeid f_employeename                                     

           1 Tom                                               
           2 Jack                                              
           3 Mary                                              

3 row(s) retrieved.

>

结论：在不提供Serial字段数值情况下，Serial字段会自动为新插入记录生成一个递增数值。

插入两条记录，输入员工ID和员工姓名

insert into t_employee(f_employeeid, f_employeename) values(5, 'Henry');
insert into t_employee(f_employeeid, f_employeename) values(8, 'Rose');

查询员工ID和员工姓名

> select f_employeeid, f_employeename from t_employee;


f_employeeid f_employeename                                     

           1 Tom                                               
           2 Jack                                              
           3 Mary                                              
           5 Henry                                             
           8 Rose                                              

5 row(s) retrieved.

>

结论：在提供Serial字段数值情况下，新插入记录的Serial字段使用提供的数值，不再自动生成新值。

插入一条记录，只输入员工姓名

insert into t_employee(f_employeename) values('Bill');

查询员工ID和员工姓名

> select f_employeeid, f_employeename from t_employee;


f_employeeid f_employeename                                     

           1 Tom                                               
           2 Jack                                              
           3 Mary                                              
           5 Henry                                             
           8 Rose                                              
           9 Bill                                              

6 row(s) retrieved.

>

结论：当新插入的数据未提供Serial字段数值时，新记录的Serial字段值为当前表记录最大值加1。

插入一条记录，输入员工ID和员工姓名

insert into t_employee(f_employeeid, f_employeename) values(6, 'Kate');

查询员工ID和员工姓名

> select f_employeeid, f_employeename from t_employee;


f_employeeid f_employeename                                     

           1 Tom                                               
           2 Jack                                              
           3 Mary                                              
           5 Henry                                             
           8 Rose                                              
           9 Bill                                              
           6 Kate                                              

7 row(s) retrieved.

>

插入一条记录，输入员工姓名

insert into t_employee(f_employeename) values('Bob');

查询员工ID和员工姓名

> select f_employeeid, f_employeename from t_employee;


f_employeeid f_employeename                                     

           1 Tom                                               
           2 Jack                                              
           3 Mary                                              
           5 Henry                                             
           8 Rose                                              
           9 Bill                                              
           6 Kate                                              
          10 Bob                                               

8 row(s) retrieved.

>

结论：当Serial字段数值出现【空位置】时，可以指定确定的值进入插入。

—3.3 验证money类型

更新Bill的f_salary字段

update t_employee set f_salary = 1234567890.1234 where f_employeeid = 9;

查询员工ID,员工姓名，薪水

> select f_employeeid, f_employeename, f_salary from t_employee where f_employeeid > 8;



f_employeeid    9
f_employeename  Bill
f_salary        RMB 1234567890.12

f_employeeid    10
f_employeename  Bob
f_salary        

2 row(s) retrieved.

>

unload to '/home/gbasedbt/employee.txt' delimiter ',' 
select f_employeeid, f_employeename, f_salary 
from t_employee 
where f_employeeid > 8;

结论：Money类型会根据本地化设置，自动显示相应的货币符号和保留对应的小数位数，但数据本身仍然是一个定点小数，并不存储有关货币符号的信息。

—3.4 验证date类型

默认的date类型格式为月/日/年（如06/18/2020），当未设置任何有关date数据类型的环境变量时

> update t_employee set f_joindate = '06/18/2020' where f_employeeid = 1;

1 row(s) updated.

执行date数据操作时，如果日期格式不匹配，可能出现下面的错误

> update t_employee set f_joindate = '2020-06-18' where f_employeeid = 1;

 1205: Invalid month in date
Error in line 1
Near character position 69
>

设置如下环境变量，设置自己使用的日期格式

export GL_DATE="%iY-%m-%d"

再次执行更新操作

> !echo $GL_DATE
%iY-%m-%d
> update t_employee set f_joindate = '2020-06-18' where f_employeeid = 1;

1 row(s) updated.

> select f_employeeid, f_employeename,f_joindate from t_employee where f_employeeid = 1;


f_employeeid f_employeename                                     f_joindate 

           1 Tom                                                2020-06-18

1 row(s) retrieved.

>

结论：GBase 8s可以根据数据中日期的具体格式，设置对应的GL_DATE，完成日期格式的输入。

—3.5 验证datetime类型

默认的datetime类型格式为【2020-06-18 12:34:56】

update t_employee set f_inputdate = '2020-06-18 12:34:56' where f_employeeid = 2;

直接使用年月日时分秒的格式（如2020-06-18 12:34:56），更新datetime字段。

> update t_employee set f_inputdate = '2020-06-18 12:34:56' where f_employeeid = 2;

1 row(s) updated.

> select f_employeeid, f_employeename,f_inputdate from t_employee where f_employeeid = 2;



f_employeeid    2
f_employeename  Jack
f_inputdate     2020-06-18 12:34:56

1 row(s) retrieved.

>

—3.6 验证int,float,decimal类型

通过员工ID，更新员工年龄

update t_employee set f_age = 28 where f_employeeid = 1;

查询员工ID,员工姓名，年龄

> update t_employee set f_age = 28 where f_employeeid = 1;

1 row(s) updated.

> select f_employeeid, f_employeename, f_age from t_employee where f_employeeid = 1;


f_employeeid f_employeename                                           f_age 

           1 Tom                                                         28

1 row(s) retrieved.

>

通过员工ID，更新员工体重

update t_employee set f_weight = 56.78 where f_employeeid = 1;

查询员工ID,员工姓名，体重

> update t_employee set f_weight = 56.78 where f_employeeid = 1;

1 row(s) updated.

> select f_employeeid, f_employeename, f_weight from t_employee where f_employeeid = 1;

f_employeeid    1
f_employeename  Tom
f_weight        56.78000000000

1 row(s) retrieved.

>

通过员工ID，更新员工身高

update t_employee set f_height = 1.86 where f_employeeid = 1;

查询员工ID,员工姓名，身高

> update t_employee set f_height = 1.86 where f_employeeid = 1;

1 row(s) updated.

> select f_employeeid, f_employeename, f_height from t_employee where f_employeeid = 1;



f_employeeid    1
f_employeename  Tom
f_height        1.860000

1 row(s) retrieved.

>

4 总结

GBase 8s 支持多种数据类型。

GBase 8s 的基本数据类型，多数与其它数据库产品兼容。

GBase 8s 提供了一些特有的数据类型，如Serial，Money，方便用户使用。

GBase 8s 的日期时间类型，可通过环境变量设置，定义日期时间格式，方便用户使用。