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Oracle 批量更新sequence的存储

Jun 07, 2016 pm 04:43 PM

前言: Oracle的序列(SEQUENCE)A SCHEMA OBJECT THAT GENERATES A SERIAL LIST OF UNIQUE NUMBERS FOR TABLE COLUMNS.TO USE A

前言:

Oracle的序列(SEQUENCE)A SCHEMA OBJECT THAT GENERATES A SERIAL LIST OF UNIQUE NUMBERS FOR TABLE COLUMNS.TO USE A SEQUENCE ,YOUR SCHEMA MUST CONTAIN THE SEQUENCE OR YOU MUST HAVE BEEN GRANTED THE SELECT OBJECT PRIVILEGE FOR ANOTHER USER IS SEQUENCE.ONCE A SEQUENCE IS DEFINED,IT CAN BE ACCESSED AND INCREMENTED BY MULTIPLE USERS(WHO HAVE SELECT OBJECT PRIVILEGE FOR THE SEQUENCE CONTAINING THE SEQUENCE)WITH NO WAITING.THE DATABASE DOES NOT WAIT FOR A TRANSACTION THAT HAS INCREMENTED A SEQUENCE TO COMPLETE BEFORE THAT SEQUENCE CAN BE INCREMENTED AGAIN. 

简单说:序列一般用于自动递增生成主键值 ..

但是否有一些情况会导致调用SEQ_....NEXTVAL时大于主键最大值呢?

场景:

  主键表 -> T表 '100W'数据同步到T1表(同步:TRUNCATE/DELETE或IMPDP...等方式[手动改数据])

  例如: T表对应SEQ_T.NEXTVAL= 100W;

        T1表对应SEQ_T.NEXTVAL= 10W;

        TRUNCATE TABLE T1;

        INSERT TABLE T1 SELECT * FROM T;

        数据同步但T1表对应SEQ_T.NEXTVAL= 10W序列不变;

        此时T1调用序列INSERT到T1表时就会报错 ( ORA-00001 : 违反唯一约束条件 (LOTTERY.PK_T1))

        (若批量同步很多表就可能会引起很多表序列需要更新成主键最大值+ 1才能保证不报错

        (可以用把源库的SEQUENCE同步过来①或者如下存储解决② ))

  ①PLSQL 工具的COMPARE USER OBJECTS可以解决SEQUENCE序列对象同步到其他环境...在此就不细说了

  ②我们环境序列一般都是由SEQ_表名字组成.所以写批量更新存储的时候比较方便~

  如下存储针对常用于以上场景的环境,,生产环境不批量导新数据/同步用户数据/表数据 就很少用到...也可只提供参考...

--批量更新序列存储--
CREATE OR REPLACE PROCEDURE P_SYNCSEQ(USERNAME VARCHAR2 /*传入要检查/更新序列的用户*/ ) IS

  /*

  **@AUTHOR 毛海晴

  ORACLE 批量更新SEQUENCE

  注释:

    批量更新SEQUENCE,

    更新序列下一个值 = 主键最大值+1

    ---序列创建时,属性NOMAXVALUE=最大值是10的28次方

  思路:

    1、找到每个表主键列 且在该表主键最大值是什么?

    2、找到表对应SEQUENCE值 与 表主键最大值去对比。

    如果SEQUENCE 下一个值大于表主键最大值就不做更新;
 

    否则需要进行更新(2中更新方式)

    1)删除SEQUENCE ,创建新序列开始值为表主键最大值+1;  --本文选择此方案...嘿嘿~

    (坏处:赶好在DROP SEQUENCE..而程序也恰巧调用依赖它的函数和存储过程将失效

    但 后续CREATE SEQUENCE了,再调用了会重新编译 调用..不会报错....有实验过哦~)

    2)ALTER SEQUENCE .. INCREMENT BY .. NOCACHE;

      SELECT ...NEXTVAL FROM DUAL;

      ALTER SEQUENCE .. INCREMENT BY 1 CACHE 20;

    .... sequence.nextval其实也可以用user_sequences.last_number字段实现..由于最早存储就这样的写就没改~...谅解~

    SEQUENCE和表名长度最大限制是30

    SEQUENCE规范的名字SEQ_+表名字    -- 此处规范只是管理维护方便而已 并不是非要这样要求

    如果表名长度大小大于26 加上"SEQ_"就大于了SEQUENCE长度限制的30

    若表名长度大于26,那对应序列肯定不是规范命名(SEQ_表名字),再由于这样的序列并不多,所以将这些一一处理

    在更新前可先注释掉EXECUTE IMMEDIATE,先作下测试看下效果,免得EXECUTE IMMEDIATE DROP .后创建报错,导致在调用 序列不会创建,也校验不到序列

 

    所需权限:
    -- 创建序列权限 --

    -- Grant/Revoke system privileges
    grant create sequence to LOTTERY;
    --查询权限--
    -- Grant/Revoke object privileges
    grant select on DBA_CONSTRAINTS to LOTTERY;
    grant select on DBA_CONS_COLUMNS to LOTTERY;
    grant select on DBA_SEQUENCES to LOTTERY;
    grant select on DBA_TABLES to LOTTERY;
    grant select on DBA_TAB_COLUMNS to LOTTERY;
      --或者--
      -- Grant/Revoke system privileges
      grant select any dictionary to LOTTERY;
 

 */


 

  --变量

  MAX_ID            NUMBER(12 ); 

  P_SEQ_NUM          NUMBER(12 );

  P_TABLE_NAME      VARCHAR2(50 );

  P_COLUMN          VARCHAR2(50 );

  P_SEQUENCE        VARCHAR2(50 );

  P_SQL              VARCHAR2(500 );

  P_SEQ_SQL          VARCHAR2(5000 );

  P_SQL_SEQ          VARCHAR2(30000 );

  P_NEW_COUNT        NUMBER(12 );


 

  --查询表长度小于26 的表/序列

  --游标

  CURSOR C_CONS IS -- 查询表长度小于26 的表/序列

    SELECT T1.TABLE_NAME    TABLE_NAME,

          T1.COLUMN_NAME    COLUMN_NAME,

          T1.SEQUENCE_NAME1 SEQUENCE_NAME

      FROM ((SELECT C.TABLE_NAME,

                    CASE

                      WHEN C1.DATA_TYPE = 'NUMBER' THEN

                      C.COLUMN_NAME

                      ELSE

                      'TO_NUMBER(' || C.COLUMN_NAME || ')'

                    END COLUMN_NAME,

                    C.SEQUENCE_NAME1

              FROM (SELECT C.TABLE_NAME,

                            C.COLUMN_NAME,

                            'SEQ_' || C.TABLE_NAME SEQUENCE_NAME1

                      FROM DBA_CONS_COLUMNS C --用户的约束对应的表列信息

                      WHERE C.OWNER = UPPER (USERNAME)

                        AND (C.CONSTRAINT_NAME, C.TABLE_NAME) IN

                            ( SELECT S.CONSTRAINT_NAME, S.TABLE_NAME

                              FROM DBA_CONSTRAINTS S --用户的对象约束信息

                              WHERE S.OWNER = (UPPER (USERNAME))

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