基于ORACLE建表和循环回路来创建数据库存储过程SQL语句来实现

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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