一个、概要
在实际的软件开发项目。我们经常会遇到需要创造更多的相同类型的数据库表或存储过程时，。例如。假设按照尾号点表的ID号，然后，你需要创建10用户信息表，的用户信息放在同一个表中。
对于类型同样的多个表，我们能够逐个建立，也能够採用循环的方法来建立。与之相相应的，能够用一个存储过程实现对全部表的操作。也能够循环建立存储过程，每一个存储过程实现对某个特定表的操作。
本文中，我们建立10个员工信息表。每一个表中包括员工工号(8位)和年龄字段，以工号的最后一位来分表。同一时候，我们建立存储过程实现对员工信息的插入。本文中的SQL语句基于ORACLE数据库实现。
二、一般的实现方式
在该实现方式中，我们逐个建立员工信息表，并在一个存储过程实现对全部表的操作。详细SQL语句例如以下：
建表语句：
-- tb_employeeinfo0
begin
execute immediate ‘drop table tb_employeeinfo0 cascade constraints‘;
exception when others then commit;
end;
/
create table tb_employeeinfo0
(
employeeno varchar2(10) not null, -- employee number
employeeage int not null -- employee age
);
create unique index idx1_tb_employeeinfo0 on tb_employeeinfo0(employeeno);
prompt ‘create table tb_employeeinfo0 ok‘;
commit;
-- tb_employeeinfo1
begin
execute immediate ‘drop table tb_employeeinfo1 cascade constraints‘;
exception when others then commit;
end;
/
create table tb_employeeinfo1
(
employeeno varchar2(10) not null, -- employee number
employeeage int not null -- employee age
);
create unique index idx1_tb_employeeinfo1 on tb_employeeinfo1(employeeno);
prompt ‘create table tb_employeeinfo1 ok‘;
commit;
-- tb_employeeinfo2
begin
execute immediate ‘drop table tb_employeeinfo2 cascade constraints‘;
exception when others then commit;
end;
/
create table tb_employeeinfo2
(
employeeno varchar2(10) not null, -- employee number
employeeage int not null -- employee age
);
create unique index idx1_tb_employeeinfo2 on tb_employeeinfo2(employeeno);
prompt ‘create table tb_employeeinfo2 ok‘;
commit;
-- tb_employeeinfo3
begin
execute immediate ‘drop table tb_employeeinfo3 cascade constraints‘;
exception when others then commit;
end;
/
create table tb_employeeinfo3
(
employeeno varchar2(10) not null, -- employee number
employeeage int not null -- employee age
);
create unique index idx1_tb_employeeinfo3 on tb_employeeinfo3(employeeno);
prompt ‘create table tb_employeeinfo3 ok‘;
commit;
-- tb_employeeinfo4
begin
execute immediate ‘drop table tb_employeeinfo4 cascade constraints‘;
exception when others then commit;
end;
/
create table tb_employeeinfo4
(
employeeno varchar2(10) not null, -- employee number
employeeage int not null -- employee age
);
create unique index idx1_tb_employeeinfo4 on tb_employeeinfo4(employeeno);
prompt ‘create table tb_employeeinfo4 ok‘;
commit;
-- tb_employeeinfo5
begin
execute immediate ‘drop table tb_employeeinfo5 cascade constraints‘;
exception when others then commit;
end;
/
create table tb_employeeinfo5
(
employeeno varchar2(10) not null, -- employee number
employeeage int not null -- employee age
);
create unique index idx1_tb_employeeinfo5 on tb_employeeinfo5(employeeno);
prompt ‘create table tb_employeeinfo5 ok‘;
commit;
-- tb_employeeinfo6
begin
execute immediate ‘drop table tb_employeeinfo6 cascade constraints‘;
exception when others then commit;
end;
/
create table tb_employeeinfo6
(
employeeno varchar2(10) not null, -- employee number
employeeage int not null -- employee age
);
create unique index idx1_tb_employeeinfo6 on tb_employeeinfo6(employeeno);
prompt ‘create table tb_employeeinfo6 ok‘;
commit;
-- tb_employeeinfo7
begin
execute immediate ‘drop table tb_employeeinfo7 cascade constraints‘;
exception when others then commit;
end;
/
create table tb_employeeinfo7
(
employeeno varchar2(10) not null, -- employee number
employeeage int not null -- employee age
);
create unique index idx1_tb_employeeinfo7 on tb_employeeinfo7(employeeno);
prompt ‘create table tb_employeeinfo7 ok‘;
commit;
-- tb_employeeinfo8
begin
execute immediate ‘drop table tb_employeeinfo8 cascade constraints‘;
exception when others then commit;
end;
/
create table tb_employeeinfo8
(
employeeno varchar2(10) not null, -- employee number
employeeage int not null -- employee age
);
create unique index idx1_tb_employeeinfo8 on tb_employeeinfo8(employeeno);
prompt ‘create table tb_employeeinfo8 ok‘;
commit;
-- tb_employeeinfo9
begin
execute immediate ‘drop table tb_employeeinfo9 cascade constraints‘;
exception when others then commit;
end;
/
create table tb_employeeinfo9
(
employeeno varchar2(10) not null, -- employee number
employeeage int not null -- employee age
);
create unique index idx1_tb_employeeinfo9 on tb_employeeinfo9(employeeno);
prompt ‘create table tb_employeeinfo9 ok‘;
commit;存储过程创建语句：
create or replace procedure pr_insertdata
(
v_employeeno in varchar2,
v_employeeage in int
)
as
v_employeecnt int;
v_tableindex varchar2(2);
begin
v_tableindex := substr(v_employeeno, length(v_employeeno), 1);
if v_tableindex = ‘0‘ then
begin
select count(*) into v_employeecnt from tb_employeeinfo0 where employeeno = v_employeeno;
if v_employeecnt > 0 then -- the employeeno is already in DB
begin
return;
end;
else -- the employeeno is not in DB
begin
insert into tb_employeeinfo0(employeeno, employeeage) values(v_employeeno, v_employeeage);
end;
end if;
end;
elsif v_tableindex = ‘1‘ then
begin
select count(*) into v_employeecnt from tb_employeeinfo1 where employeeno = v_employeeno;
if v_employeecnt > 0 then -- the employeeno is already in DB
begin
return;
end;
else -- the employeeno is not in DB
begin
insert into tb_employeeinfo1(employeeno, employeeage) values(v_employeeno, v_employeeage);
end;
end if;
end;
elsif v_tableindex = ‘2‘ then
begin
select count(*) into v_employeecnt from tb_employeeinfo2 where employeeno = v_employeeno;
if v_employeecnt > 0 then -- the employeeno is already in DB
begin
return;
end;
else -- the employeeno is not in DB
begin
insert into tb_employeeinfo2(employeeno, employeeage) values(v_employeeno, v_employeeage);
end;
end if;
end;
elsif v_tableindex = ‘3‘ then
begin
select count(*) into v_employeecnt from tb_employeeinfo3 where employeeno = v_employeeno;
if v_employeecnt > 0 then -- the employeeno is already in DB
begin
return;
end;
else -- the employeeno is not in DB
begin
insert into tb_employeeinfo3(employeeno, employeeage) values(v_employeeno, v_employeeage);
end;
end if;
end;
elsif v_tableindex = ‘4‘ then
begin
select count(*) into v_employeecnt from tb_employeeinfo4 where employeeno = v_employeeno;
if v_employeecnt > 0 then -- the employeeno is already in DB
begin
return;
end;
else -- the employeeno is not in DB
begin
insert into tb_employeeinfo4(employeeno, employeeage) values(v_employeeno, v_employeeage);
end;
end if;
end;
elsif v_tableindex = ‘5‘ then
begin
select count(*) into v_employeecnt from tb_employeeinfo5 where employeeno = v_employeeno;
if v_employeecnt > 0 then -- the employeeno is already in DB
begin
return;
end;
else -- the employeeno is not in DB
begin
insert into tb_employeeinfo5(employeeno, employeeage) values(v_employeeno, v_employeeage);
end;
end if;
end;
elsif v_tableindex = ‘6‘ then
begin
select count(*) into v_employeecnt from tb_employeeinfo6 where employeeno = v_employeeno;
if v_employeecnt > 0 then -- the employeeno is already in DB
begin
return;
end;
else -- the employeeno is not in DB
begin
insert into tb_employeeinfo6(employeeno, employeeage) values(v_employeeno, v_employeeage);
end;
end if;
end;
elsif v_tableindex = ‘7‘ then
begin
select count(*) into v_employeecnt from tb_employeeinfo7 where employeeno = v_employeeno;
if v_employeecnt > 0 then -- the employeeno is already in DB
begin
return;
end;
else -- the employeeno is not in DB
begin
insert into tb_employeeinfo7(employeeno, employeeage) values(v_employeeno, v_employeeage);
end;
end if;
end;
elsif v_tableindex = ‘8‘ then
begin
select count(*) into v_employeecnt from tb_employeeinfo8 where employeeno = v_employeeno;
if v_employeecnt > 0 then -- the employeeno is already in DB
begin
return;
end;
else -- the employeeno is not in DB
begin
insert into tb_employeeinfo8(employeeno, employeeage) values(v_employeeno, v_employeeage);
end;
end if;
end;
elsif v_tableindex = ‘9‘ then
begin
select count(*) into v_employeecnt from tb_employeeinfo9 where employeeno = v_employeeno;
if v_employeecnt > 0 then -- the employeeno is already in DB
begin
return;
end;
else -- the employeeno is not in DB
begin
insert into tb_employeeinfo9(employeeno, employeeage) values(v_employeeno, v_employeeage);
end;
end if;
end;
end if;
commit;
exception when others then
begin
rollback;
return;
end;
end;
/
prompt ‘create procedure pr_insertdata ok‘三、循环创建的实现方式
在该实现方式中，我们採用循环的方法建立员工信息表及存储过程。详细SQL语句例如以下：
建表语句：
-- tb_employeeinfo0~9
begin
declare i int;tmpcount int;tbname varchar2(50);strsql varchar2(1000);
begin
i:=0;
while i<10 loop
begin
tbname := ‘tb_employeeinfo‘||to_char(i);
i := i+1;
select count(1) into tmpcount from user_tables where table_name = Upper(tbname);
if tmpcount>0 then
begin
execute immediate ‘drop table ‘||tbname;
commit;
end;
end if;
strsql := ‘create table ‘||tbname||
‘(
employeeno varchar2(10) not null, -- employee number
employeeage int not null -- employee age
)‘;
execute immediate strsql;
strsql := ‘begin
execute immediate ‘‘drop index idx1_‘||tbname || ‘ ‘‘‘
|| ‘;exception when others then null;
end;‘;
execute immediate strsql;
execute immediate ‘create unique index idx1_‘||tbname||‘ on ‘||tbname||‘(employeeno)‘;
end;
end loop;
end;
end;
/存储过程创建语句：
begin
declare v_i int;v_procname varchar(50);v_employeeinfotbl varchar(50);strsql varchar(4000);
begin
v_i := 0;
while v_i < 10 loop
v_procname := ‘pr_insertdata‘||substr(to_char(v_i),1,1);
v_employeeinfotbl := ‘tb_employeeinfo‘||substr(to_char(v_i),1,1);
v_i := v_i + 1;
strsql := ‘create or replace procedure ‘||v_procname||‘(
v_employeeno in varchar2,
v_employeeage in int
)
as
v_employeecnt int;
begin
select count(*) into v_employeecnt from ‘||v_employeeinfotbl||‘ where employeeno = v_employeeno;
if v_employeecnt > 0 then -- the employeeno is already in DB
begin
return;
end;
else -- the employeeno is not in DB
begin
insert into ‘||v_employeeinfotbl||‘(employeeno, employeeage) values(v_employeeno, v_employeeage);
end;
end if;
commit;
exception when others then
begin
rollback;
return;
end;
end;‘;
execute immediate strsql;
end loop;
end;
end;
/四、总结
当同样类型的表的个数较多时(如有上百个)。显然用循环创建的实现方式能够节约大量的工作时间，提高工作效率。可是，在使用该方法的时候，要特别细致，尤其要注意单引號的使用，避免为了省事而引入代码逻辑问题。
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时间： 2024-09-28 23:09:22