pl/sql 实例精解 03

1. 在Pl/sql 中使用 sql

   1:  /*

   2:   * 一个 pl/sql 语句块, 只是一个容器, 是表明一个整体的容器, 容器里可以放置多个sql语句

   3:  */

   4:   

   5:  declare 

   6:      v_zip    zipcode.zip%type;

   7:      v_user    zipcode.created_by%type;

   8:      v_date    zipcode.created_date%type;

   9:  begin

  10:      -- statement 1

  11:      select 43438, user, sysdate

  12:        into v_zip, v_user, v_date

  13:        from dual;

  14:      

  15:      -- statement 2

  16:      insert into zipcode(zip, created_by, careate_date, modified_by,

  17:                          modified_date)

  18:      values(v_zip, v_user, v_date, v_user,

  19:              v_date);

  20:  end;

  21:  /

  22:  show errors;

  23:      

2. 在 pl/sql 中使用 commit, rollback, savepoint

   1:  /*

   2:   * ROLLBACK [WORK] to SAVEPOINT name;

   3:  */

   4:   

   5:  begin

   6:      insert into student(student_id, last_name, zip, reistration_date,

   7:                          created_by, created_date, modified_by, modified_date)

   8:      values(student_id_seql.nextval, 'Tashi', 10015, '01-一月-99',

   9:              'Student', '01-一月-99', 'studenta', '01-一月-99');

  10:      savepoint A;        -- A is work name

  11:      

  12:      insert into student(student_id, last_name, zip, reistration_date,

  13:                          created_by, created_date, modified_by, modified_date)

  14:      values(student_id_seql.nextval, 'bbb', 10015, '01-一月-99',

  15:              'Student', '01-一月-99', 'studentb', '01-一月-99');

  16:      savepoint B;        -- B is work name

  17:      

  18:      insert into student(student_id, last_name, zip, reistration_date,

  19:                          created_by, created_date, modified_by, modified_date)

  20:      values(student_id_seql.nextval, 'ccc', 10015, '01-一月-99',

  21:              'Student', '01-一月-99', 'studentc', '01-一月-99');

  22:      savepoint C;        -- C is work name

  23:      

  24:      rollback to b;

  25:  end;

如上代码执行完后, 由于 rollback to b, 所以, 第3段代码执行的插入操作就会被rollback, 所以最后的结果是插入了2条记录.

所以, 综上, rollback 到之前的一个保存点 savepoint, 那么该保存点之下的所有sql语句都会被rollback, 而保存点savepoint之上的sql没有被rollback.