在Oracle運行作業系統命令

oracle 在Oracle 8i中,往往會出現要在預存程序中運行作業系統命令的情況.一般來說,利用Oracle Enterprise Manager設定作業時可以達到這個目的.但是由於OEM在設定作業缺乏靈活性,設定的作業的參數是固定的.在實際應用當中往往需要在SQL語句當中運行需要隨時運行作業系統命令.Oracle 8i沒有直接運行OS命令的語句,我們可以利用DBMS_PIPE程式包實現這一要求.DBMS_PIPE通過建立管道,可以讓至少兩個進程進行通訊.Oracle的管道與作業系統的管道在概念上有相同的地方,但是在實現機制不同.下面介紹實現具體步驟:1 建立一個程式包,姑且起名叫DAEMON,SQL語句如下:/*建立daemon程式包*/CREATE OR REPLACE PACKAGE BODY daemon AS/*execute_system是實現運行os命令的函數*/FUNCTION execute_system(command VARCHAR2,timeout NUMBER DEFAULT 10)RETURN NUMBER ISstatus NUMBER;result VARCHAR2(20);command_code NUMBER;pipe_name VARCHAR2(30);BEGINpipe_name := DBMS_PIPE.UNIQUE_SESSION_NAME;DBMS_PIPE.PACK_MESSAGE('SYSTEM');DBMS_PIPE.PACK_MESSAGE(pipe_name);DBMS_PIPE.PACK_MESSAGE(command);/*向daemon管道發送表示命令的字元*/status := DBMS_PIPE.SEND_MESSAGE('daemon', timeout);IF status <> 0 THENRAISE_APPLICATION_ERROR(-20010,'Execute_system: Error while sending. Status = ' || status);END IF;status := DBMS_PIPE.RECEIVE_MESSAGE(pipe_name, timeout);IF status <> 0 THENRAISE_APPLICATION_ERROR(-20011,'Execute_system: Error while receiving. Status = ' || status);END IF;/*擷取返回結果*/DBMS_PIPE.UNPACK_MESSAGE(result);IF result <> 'done' THENRAISE_APPLICATION_ERROR(-20012,'Execute_system: Done not received.');END IF;DBMS_PIPE.UNPACK_MESSAGE(command_code);DBMS_OUTPUT.PUT_LINE('System command executed. result = ' ||command_code);RETURN command_code;END execute_system;/*stop是讓daemon停止*/PROCEDURE stop(timeout NUMBER DEFAULT 10) ISstatus NUMBER;BEGINDBMS_PIPE.PACK_MESSAGE('STOP');status := DBMS_PIPE.SEND_MESSAGE('daemon', timeout);IF status <> 0 THENRAISE_APPLICATION_ERROR(-20030,'stop: error while sending. status = ' || status);END IF;END stop;END daemon;通過Sql*Plus運行以上語句,將為目前使用者建立daemon程式包.2 建立在OS上啟動並執行守護進程,監聽由上面的daemon程式包發來的要求執行os命令的語句.以下Pro*C的代碼,必須由pro*c先進行先行編譯.#include #include EXEC SQL INCLUDE SQLCA;EXEC SQL BEGIN DECLARE SECTION;char *uid = "scott/tiger";/*在這個地方改為你自己訪問的使用者,密碼,服務名*/int status;VARCHAR command[20];VARCHAR value[2000];VARCHAR return_name[30];EXEC SQL END DECLARE SECTION;voidconnect_error(){char msg_buffer[512];int msg_length;int buffer_size = 512;EXEC SQL WHENEVER SQLERROR CONTINUE;sqlglm(msg_buffer, &buffer_size, &msg_length);printf("Daemon error while connecting:\n");printf("%.*s\n", msg_length, msg_buffer);printf("Daemon quitting.\n");exit(1);}voidsql_error(){char msg_buffer[512];int msg_length;int buffer_size = 512;EXEC SQL WHENEVER SQLERROR CONTINUE;sqlglm(msg_buffer, &buffer_size, &msg_length);printf("Daemon error while executing:\n");printf("%.*s\n", msg_length, msg_buffer);printf("Daemon continuing.\n");}main(){EXEC SQL WHENEVER SQLERROR DO connect_error();EXEC SQL CONNECT :uid;printf("Daemon connected.\n");EXEC SQL WHENEVER SQLERROR DO sql_error();printf("Daemon waiting...\n");while (1) {EXEC SQL EXECUTEBEGIN/*接收deamon發來的字元*/:status := DBMS_PIPE.RECEIVE_MESSAGE('daemon');IF :status = 0 THEN/*取出字元*/DBMS_PIPE.UNPACK_MESSAGE(:command);END IF;END;END-EXEC;IF (status == 0){command.arr[command.len] = '\0';/*如果是stop,該進程就退出*/IF (!strcmp((char *) command.arr, "STOP")){printf("Daemon exiting.\n");break;}ELSE IF (!strcmp((char *) command.arr, "SYSTEM")){EXEC SQL EXECUTEBEGINDBMS_PIPE.UNPACK_MESSAGE(:return_name);DBMS_PIPE.UNPACK_MESSAGE(:value);END;END-EXEC;value.arr[value.len] = '\0';printf("Will execute system command '%s'\n", value.arr);/*運行os命令*/status = system(value.arr);EXEC SQL EXECUTEBEGINDBMS_PIPE.PACK_MESSAGE('done');DBMS_PIPE.PACK_MESSAGE(:status);:status := DBMS_PIPE.SEND_MESSAGE(:return_name);END;END-EXEC;IF (status){printf("Daemon error while responding to system command.");printf(" status: %d\n", status);}}ELSE{printf("Daemon error: invalid command '%s' received.\n",command.arr);}}ELSE{printf("Daemon error while waiting for signal.");printf(" status = %d\n", status);}}EXEC SQL COMMIT WORK RELEASE;exit(0);}以上代碼起名為daemon.pc,用proc先行編譯:proc iname=daemon.pc userid=使用者名稱/密碼@服務名 sqlcheck=semantics得到daemon.c,在用c進行編譯,注意在NT上要把orasql8.lib加上,否則編譯通過,串連沒法通過.3 在伺服器上運行daemon.exe

4 在sqlplus運行測試語句:SQL> variable rv numberSQL> execute :rv := DAEMON.EXECUTE_SYSTEM('ls -la');PL/SQL 過程已成功完成。SQL> execute :rv := DAEMON.EXECUTE_SYSTEM('dir');PL/SQL 過程已成功完成。SQL>DBMS_PIPE的用法見oracle的文檔.