\u6709\u670b\u53cb\u95ee\u6211\u80fd\u5426\u7528\u89e6\u53d1\u5668\u5b9e\u73b0\u66f4\u65b0\u6570\u636e\u65f6\uff0c\u5982\u679c\u53d1\u73b0\u4e3b\u952e\u5df2\u7ecf\u5b58\u5728\uff0c\u5219\u5c06\u51b2\u7a81\u7684\u4e3b\u952e\u66f4\u65b0\u4e3a\u5f53\u524d\u8bb0\u5f55\u4e4b\u524d\u7684\u4e3b\u952e\u503c\u3002
\n\u7b80\u5355\u7684\u8bf4\uff0c\u5982\u679c\u8868\u4e2d\u5b58\u5728\u4e3b\u952e\u4e3a1\u548c2\u7684\u8bb0\u5f55\uff0c\u5982\u679c\u4e00\u6761UPDATE\u8bed\u53e5\u5c061\u66f4\u65b0\u4e3a2\uff0c\u90a3\u4e48\u60f3\u8981\u5b9e\u73b0\u7684\u529f\u80fd\u662f\u4e3a\u4e86\u786e\u4fdd\u8fd9\u4e2aUPDATE\u53ef\u4ee5\u6267\u884c\u6210\u529f\uff0c\u5728\u540e\u53f0\u81ea\u52a8\u5c06ID\u4e3a2\u7684\u8bb0\u5f55\u66f4\u65b0\u4e3a1\u3002
\n\u8fd9\u4e2a\u529f\u80fd\u5e94\u8be5\u53ef\u4ee5\u5b9e\u73b0\uff0c\u4f46\u662f\u76f4\u63a5\u5728\u89e6\u53d1\u5668\u4e2d\u80af\u5b9a\u65e0\u6cd5\u5b9e\u73b0\uff0c\u56e0\u4e3a\u8fd9\u662f\u4e00\u4e2a\u6807\u51c6\u7684\u53d8\u5f02\u8868\u95ee\u9898\u3002\u800c\u4e14\u5373\u4f7f\u662f\u91c7\u7528\u81ea\u6cbb\u4e8b\u52a1\u7684\u65b9\u5f0f\uff0c\u4e5f\u9700\u8981\u5c0f\u5fc3\uff0c\u56e0\u4e3a\u8981\u4fee\u6539\u539f\u6709\u7684\u8bb0\u5f55\u5c31\u5fc5\u987b\u901a\u8fc7UPDATE\u5b9e\u73b0\uff0c\u800c\u8fd9\u4e2aUPDATE\u53c8\u4f1a\u5bfc\u81f4\u89e6\u53d1\u5668\u7684\u89e6\u53d1\uff0c\u5982\u679c\u5904\u7406\u4e0d\u5f53\uff0c\u5c31\u4f1a\u5bfc\u81f4\u5faa\u73af\u89e6\u53d1\u3002<\/p>\n
SQL> CREATE TABLE T (ID NUMBER, NAME VARCHAR2(30), CONSTRAINT PK_T PRIMARY KEY (ID));\r\nTable created.\r\nSQL> CREATE OR REPLACE PROCEDURE P_UPDATE_T (P_NEW NUMBER, P_OLD NUMBER) AS\r\n 2 BEGIN\r\n 3 FOR I IN (SELECT ID FROM T WHERE ID = P_NEW) LOOP\r\n 4 UPDATE T SET ID = P_OLD WHERE ID = I.ID;\r\n 5 END LOOP;\r\n 6 END;\r\n 7 \/\r\nProcedure created.\r\nSQL> INSERT INTO T SELECT ROWNUM, TNAME FROM TAB WHERE ROWNUM < 5;\r\n4 rows created.\r\nSQL> COMMIT;\r\nCommit complete.\r\nSQL> CREATE OR REPLACE TRIGGER TRI_B_T \r\n 2 BEFORE UPDATE ON T\r\n 3 FOR EACH ROW\r\n 4 BEGIN\r\n 5 P_UPDATE_T(:NEW.ID, :OLD.ID);\r\n 6 END;\r\n 7 \/\r\nTrigger created.\r\nSQL> SELECT * FROM T;\r\n ID NAME\r\n---------- ------------------------------\r\n 1 BIN$uo1flhazQQngRDzZK0pZWw==$0\r\n 2 BRIDGE_CROSSING\r\n 3 C_NORMAL\r\n 4 C_SINGLE\r\nSQL> UPDATE T SET ID = 3 WHERE ID = 2;\r\nUPDATE T SET ID = 3 WHERE ID = 2\r\n *\r\nERROR at line 1:\r\nORA-04091: table TEST.T is mutating, trigger\/function may not see it\r\nORA-06512: at \"TEST.P_UPDATE_T\", line 3\r\nORA-06512: at \"TEST.TRI_B_T\", line 2\r\nORA-04088: error during execution of trigger 'TEST.TRI_B_T'\r\nSQL> CREATE OR REPLACE PROCEDURE P_UPDATE_T (P_NEW NUMBER, P_OLD NUMBER) AS\r\n 2 PRAGMA AUTONOMOUS_TRANSACTION;\r\n 3 BEGIN\r\n 4 FOR I IN (SELECT ID FROM T WHERE ID = P_NEW) LOOP\r\n 5 UPDATE T SET ID = P_OLD WHERE ID = I.ID;\r\n 6 END LOOP;\r\n 7 COMMIT;\r\n 8 END;\r\n 9 \/\r\nProcedure created.\r\nSQL> UPDATE T SET ID = 3 WHERE ID = 2;\r\nUPDATE T SET ID = 3 WHERE ID = 2\r\n *\r\nERROR at line 1:\r\nORA-00060: deadlock detected while waiting for resource\r\nORA-06512: at \"TEST.P_UPDATE_T\", line 5\r\nORA-06512: at \"TEST.TRI_B_T\", line 2\r\nORA-04088: error during execution of trigger 'TEST.TRI_B_T'\r\nORA-06512: at \"TEST.P_UPDATE_T\", line 5\r\nORA-06512: at \"TEST.TRI_B_T\", line 2\r\nORA-04088: error during execution of trigger 'TEST.TRI_B_T'<\/pre>\n\u6b63\u5982\u524d\u9762\u63d0\u5230\u7684\uff0c\u5982\u679c\u76f4\u63a5\u4fee\u6539\u5219\u78b0\u5230\u53d8\u5f02\u8868\u95ee\u9898\uff0c\u5982\u679c\u60f3\u8981\u901a\u8fc7\u81ea\u6cbb\u4e8b\u52a1\u89e3\u51b3\u53d8\u5f02\u8868\u7684\u95ee\u9898\uff0c\u53c8\u4f1a\u5bfc\u81f4\u81ea\u8eab\u7684\u6b7b\u9501\u95ee\u9898\u3002
\n\u4e3a\u4e86\u89e3\u51b3\u8fd9\u4e2a\u95ee\u9898\uff0c\u9700\u8981\u4eff\u7167\u53d8\u5f02\u8868\u7684\u5e38\u89c4\u5904\u7406\u65b9\u6cd5\u6765\u89e3\u51b3\u3002\u5e38\u89c4\u5904\u7406\u65b9\u6cd5\u662f\u901a\u8fc7\u4e00\u4e2a\u5305\u8bb0\u5f55\u53d8\u91cf\uff0c\u52a0\u4e0aBEFORE\u548cAFTER\u4e24\u4e2a\u884c\u7ea7\u89e6\u53d1\u5668\u4ee5\u53ca\u4e00\u4e2a\u8bed\u53e5\u7ea7\u89e6\u53d1\u5668\u7684\u5171\u540c\u914d\u5408\u3002\u4f46\u662f\u4e00\u822c\u800c\u8a00\uff0c\u53d8\u5f02\u8868\u7684\u5904\u7406\u5e76\u4e0d\u4f1a\u5f15\u5165\u672c\u8eab\u8bb0\u5f55\u7684\u66f4\u65b0\uff0c\u800c\u5f53\u524d\u8fd8\u9700\u8981\u89e3\u51b3\u66f4\u65b0\u5f53\u524d\u8868\u5f15\u53d1\u7684\u65e0\u9650\u5faa\u73af\u95ee\u9898\u3002<\/p>\n
SQL> CREATE OR REPLACE PACKAGE P_VAR AS\r\n 2 G_STATUS NUMBER := 0;\r\n 3 END;\r\n 4 \/\r\nPackage created.\r\nSQL> CREATE OR REPLACE FUNCTION F_GET_T (P_ID NUMBER) RETURN NUMBER AS\r\n 2 PRAGMA AUTONOMOUS_TRANSACTION;\r\n 3 V_RESULT NUMBER;\r\n 4 BEGIN\r\n 5 SELECT COUNT(*) INTO V_RESULT FROM T WHERE ID = P_ID;\r\n 6 RETURN V_RESULT;\r\n 7 END;\r\n 8 \/\r\nFunction created.\r\nSQL> CREATE OR REPLACE TRIGGER TRI_B_T\r\n 2 BEFORE UPDATE ON T\r\n 3 FOR EACH ROW\r\n 4 DECLARE\r\n 5 V_RESULT NUMBER;\r\n 6 BEGIN\r\n 7 V_RESULT := F_GET_T(:NEW.ID);\r\n 8 IF V_RESULT = 1 THEN\r\n 9 :NEW.ID := -:NEW.ID;\r\n 10 P_VAR.G_STATUS := 1;\r\n 11 END IF;\r\n 12 END;\r\n 13 \/\r\nTrigger created.\r\nSQL> CREATE OR REPLACE TRIGGER TRI_A_T\r\n 2 AFTER UPDATE ON T\r\n 3 FOR EACH ROW\r\n 4 DECLARE\r\n 5 V_JOB NUMBER;\r\n 6 BEGIN\r\n 7 IF P_VAR.G_STATUS = 1 THEN\r\n 8 DBMS_JOB.SUBMIT(V_JOB, 'BEGIN\r\n 9 UPDATE T SET ID = ' || :OLD.ID || ' WHERE ID = ' || (-1 * :NEW.ID) || ';\r\n 10 COMMIT;\r\n 11 UPDATE T SET ID = ' || (-1 * :NEW.ID) || ' WHERE ID = ' || :NEW.ID || ';\r\n 12 COMMIT; \r\n 13 END;', SYSDATE);\r\n 14 P_VAR.G_STATUS := 0;\r\n 15 END IF;\r\n 16 END;\r\n 17 \/\r\nTrigger created.\r\nSQL> SELECT * FROM T;\r\n ID NAME\r\n---------- ------------------------------\r\n 1 BIN$uo1flhazQQngRDzZK0pZWw==$0\r\n 2 BRIDGE_CROSSING\r\n 3 C_NORMAL\r\n 4 C_SINGLE\r\nSQL> UPDATE T SET ID = 3 WHERE ID = 2;\r\n1 row updated.\r\nSQL> SELECT * FROM T;\r\n ID NAME\r\n---------- ------------------------------\r\n 1 BIN$uo1flhazQQngRDzZK0pZWw==$0\r\n -3 BRIDGE_CROSSING\r\n 3 C_NORMAL\r\n 4 C_SINGLE\r\nSQL> SELECT WHAT FROM USER_JOBS;\r\nWHAT\r\n-----------------------------------------------------------------------------------\r\nBEGIN\r\n UPDATE T SET ID = 2 WHERE ID = 3;\r\n COMMIT;\r\n UPDATE T SET ID = 3 WHERE ID = -3;\r\n COMMIT;\r\n END;\r\nSQL> COMMIT;\r\nCommit complete.\r\nSQL> SELECT * FROM T;\r\n ID NAME\r\n---------- ------------------------------\r\n 1 BIN$uo1flhazQQngRDzZK0pZWw==$0\r\n 3 BRIDGE_CROSSING\r\n 2 C_NORMAL\r\n 4 C_SINGLE<\/pre>\n\u6700\u7ec8\u95ee\u9898\u901a\u8fc7\u5229\u7528\u5305\u53d8\u91cf\u8bb0\u5f55\u662f\u5426\u5b58\u5728\u51b2\u7a81\u8bb0\u5f55\uff0c\u914d\u5408\u5f02\u6b65JOB\u7684\u65b9\u5f0f\u5bf9\u51b2\u7a81\u8bb0\u5f55\u8fdb\u884c\u4fee\u6539\u7684\u65b9\u5f0f\u907f\u514d\u4e86\u65e0\u9650UPDATE\u7684\u60c5\u51b5\u3002
\n\u5f53\u7136\u4e0a\u9762\u53ea\u662f\u4e00\u4e2a\u793a\u4f8b\uff0c\u5bf9\u4e8e\u9700\u8981\u540c\u65f6\u66f4\u65b0\u591a\u6761\u8bb0\u5f55\u7684\u60c5\u51b5\uff0c\u9700\u8981\u5728\u5305\u4e2d\u6784\u5efa\u4e00\u4e2a\u7c7b\u4f3c\u6620\u5c04\u8868\u7684\u7ed3\u6784\uff0c\u4ece\u800c\u8bb0\u5f55\u6bcf\u6761\u66f4\u65b0\u7684ID\u662f\u5426\u4f1a\u51fa\u73b0NEW.ID\u5b58\u5728\u7684\u60c5\u51b5\u3002
\n\u800c\u4e14\u5728\u63d0\u4ea4\u7684JOB\u4e2d\u4e5f\u5e94\u8be5\u5bf9\u4ee3\u7801\u505a\u66f4\u591a\u7684\u4fdd\u62a4\uff0c\u6bd4\u5982\u6dfb\u52a0\u5f02\u5e38\u5904\u7406\u7b49\u3002
\n\u6b64\u5916\uff0c\u8fd9\u4e2a\u95ee\u9898\u7684\u6700\u5927\u7f3a\u70b9\u5728\u4e8e\uff0c\u53ea\u6709COMMIT\u540e\u624d\u80fd\u8fbe\u5230\u9884\u671f\u76ee\u6807\uff0c\u800c\u5728\u66f4\u65b0\u4e4b\u540e\u4e14\u6ca1\u6709\u63d0\u4ea4\u4e4b\u524d\uff0c\u66f4\u65b0\u7684\u7ed3\u679c\u5e76\u4e0d\u662fUPDATE\u8bed\u53e5\u8981\u5b8c\u6210\u7684\u64cd\u4f5c\uff0c\u800c\u53ea\u662f\u4e00\u4e2a\u4e2d\u95f4\u7ed3\u679c\u3002
\n\u4e8b\u5b9e\u4e0a\uff0c\u8fd9\u4e2a\u95ee\u9898\u672c\u6765\u5c31\u4e0d\u5e94\u8be5\u7531\u89e6\u53d1\u5668\u6765\u89e3\u51b3\uff0c\u5bf9\u4e8e\u66f4\u65b0\u73b0\u6709ID\u5230\u4e00\u4e2a\u5df2\u7ecf\u5b58\u5728\u7684ID\u7684\u64cd\u4f5c\uff0c\u5e94\u8be5\u901a\u8fc7\u4e00\u6bb5PL\/SQL\u4ee3\u7801\u6765\u5b9e\u73b0\uff0c\u8fd9\u6837\u624d\u80fd\u66f4\u597d\u7684\u8003\u8651\u5e76\u53d1\uff0c\u4e8b\u52a1\u4e00\u81f4\u6027\u548c\u4e8b\u52a1\u5b8c\u6574\u6027\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"
\u6709\u670b\u53cb\u95ee\u6211\u80fd\u5426\u7528\u89e6\u53d1\u5668\u5b9e\u73b0\u66f4\u65b0\u6570\u636e\u65f6\uff0c\u5982\u679c\u53d1\u73b0\u4e3b\u952e\u5df2\u7ecf\u5b58\u5728\uff0c\u5219\u5c06\u51b2\u7a81\u7684\u4e3b\u952e\u66f4\u65b0\u4e3a\u5f53\u524d\u8bb0\u5f55\u4e4b\u524d\u7684\u4e3b\u952e\u503c\u3002 \u7b80\u5355\u7684\u8bf4\uff0c\u5982\u679c\u8868\u4e2d\u5b58\u5728\u4e3b\u952e\u4e3a1\u548c2\u7684\u8bb0\u5f55\uff0c\u5982\u679c\u4e00\u6761UPDATE\u8bed\u53e5\u5c061\u66f4\u65b0\u4e3a2\uff0c\u90a3\u4e48\u60f3\u8981\u5b9e\u73b0\u7684\u529f\u80fd\u662f\u4e3a\u4e86\u786e\u4fdd\u8fd9\u4e2aUPDATE\u53ef\u4ee5\u6267\u884c\u6210\u529f\uff0c\u5728\u540e\u53f0\u81ea\u52a8\u5c06ID\u4e3a2\u7684\u8bb0\u5f55\u66f4\u65b0\u4e3a1\u3002 \u8fd9\u4e2a\u529f\u80fd\u5e94\u8be5\u53ef\u4ee5\u5b9e\u73b0\uff0c\u4f46\u662f\u76f4\u63a5\u5728\u89e6\u53d1\u5668\u4e2d\u80af\u5b9a\u65e0\u6cd5\u5b9e\u73b0\uff0c\u56e0\u4e3a\u8fd9\u662f\u4e00\u4e2a\u6807\u51c6\u7684\u53d8\u5f02\u8868\u95ee\u9898\u3002\u800c\u4e14\u5373\u4f7f\u662f\u91c7\u7528\u81ea\u6cbb\u4e8b\u52a1\u7684\u65b9\u5f0f\uff0c\u4e5f\u9700\u8981\u5c0f\u5fc3\uff0c\u56e0\u4e3a\u8981\u4fee\u6539\u539f\u6709\u7684\u8bb0\u5f55\u5c31\u5fc5\u987b\u901a\u8fc7UPDATE\u5b9e\u73b0\uff0c\u800c\u8fd9\u4e2aUPDATE\u53c8\u4f1a\u5bfc\u81f4\u89e6\u53d1\u5668\u7684\u89e6\u53d1\uff0c\u5982\u679c\u5904\u7406\u4e0d\u5f53\uff0c\u5c31\u4f1a\u5bfc\u81f4\u5faa\u73af\u89e6\u53d1\u3002 SQL> CREATE TABLE T (ID NUMBER, NAME VARCHAR2(30), CONSTRAINT PK_T PRIMARY KEY (ID)); Table created. SQL> CREATE OR REPLACE PROCEDURE P_UPDATE_T (P_NEW NUMBER, P_OLD NUMBER) AS 2 BEGIN 3 FOR I IN (SELECT ID FROM T WHERE … Continue reading