SQL写法规范（创建，更新等）

SQL写法规范

一、创建表

declare
cnt integer;
begin
select count(0)
into cnt
from user_all_tables
where table_name = upper('Student_Info');

if cnt = 0 then
execute immediate 'CREATE TABLE STUDENT_INFO
( ID VARCHAR2(12) NOT NULL)';
end if;
end;
/

二、增加约束

declare
cnt integer;
begin
select count(0)
into cnt
from user_constraints a
where a.constraint_name = upper('STUDENT_UK');

if cnt = 0 then
execute immediate 'ALTER TABLE STUDENT ADD CONSTRAINT STUDENT_UK UNIQUE(ID) ENABLE';
end if;
end;

三、更新表字段大小

declare cnt integer;
begin
select count(0)
into cnt
from user_tab_columns a
where a.Table_name = upper('STUDENT')
and a.COLUMN_NAME = upper('ID')
and a.DATA_LENGTH < 32;

if cnt = 1 then
execute immediate 'ALTER TABLE STUDENT modify ID VARCHAR2(64)';
end if;
end;

四、创建序列

declare
cnt integer;
begin
select count(0)
into cnt
from user_sequences a
where a.sequence_name = upper('STUDENT_SEQ');

if cnt = 0 then
execute immediate 'create sequence STUDENT_SEQ MINVALUE 1 MAXVALUE 999999999999999999999999999 INCREMENT BY 1 START WITH 1 CACHE 20 NOORDER  NOCYCLE';
end if;
end;
/

五、创建索引

declare
cnt integer;
begin
select count(0)
into cnt
from user_indexes a
where a.index_name = upper('UK_ID') and a.table_name = upper('STUDENT');
if cnt = 0 then
execute immediate 'create unique index UK_ID on STUDENT (
ID ASC)';
end if;
end;
/

六、增加列

declare
cnt integer;
begin
select count(0)
into cnt
from user_tab_columns a
where a.Table_name = upper('STUDENT')
and a.COLUMN_NAME = upper('NAME');

if cnt = 0 then
execute immediate 'ALTER TABLE STUDENT ADD NAME varchar2(22)';
end if;
end;
/

七、删除序列和索引

declare
cnt integer;
begin
select count(0)
into cnt
from user_constraints a
where a.constraint_name = upper('PK_STUDENT');

if (cnt > 0) then
execute immediate 'alter table cnaps drop constraint PK_STUDENT';
end if;

select count(0)
into cnt
from user_indexes a
where a.index_name=upper('PK_STUDENT');

if (cnt > 0) then
execute immediate 'drop index PK_STUDENT';
end if;

end;
/

命名规则：

update: *.SQL

create table: *.TAB

create sequence: *SEQ.PDC

create procedure: *.PRC

create view: VM_*.VM

批量执行sql文件：

文件内容（*.pdc)：

@目录\sql1.PDC;

@目录\sql2.PDC;

通过pl/sql打开command script 然后找到批量执行文件*.pdc，然后选择“执行”