Oracle® Streams Advanced Queuing User's Guide and Reference 10g Release 2 (10.2) Part Number B14257-01 |
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This appendix presents examples using the Oracle Streams Advanced Queuing (AQ) Pro*C/C++ interface. You must set up data structures similar to the following for certain examples to work.
$ cat >> message.typ case=lower type aq.message_typ $ $ ott userid=aq/aq intyp=message.typ outtyp=message_o.typ \ code=c hfile=demo.h $ $ proc intyp=message_o.typ iname=program name \ config=config file SQLCHECK=SEMANTICS userid=aq/aq $ cat >> message.typ case=lower type aq.message_typ $ $ ott userid=aq/aq intyp=message.typ outtyp=message_o.typ \ code=c hfile=demo.h $ $ proc intyp=message_o.typ iname=program name \ config=config file SQLCHECK=SEMANTICS userid=aq/aq
This appendix contains these topics:
Enqueuing and Dequeuing Object Type Messages Using Pro*C/C++
Enqueuing and Dequeuing Messages by Correlaton and Message ID Using Pro*C/C++
This section provides an example that enqueues and dequeues object type messages using Pro*C/C++.
Example D-1 Enqueuing and Dequeuing Object Type Messages (Pro*C/C++)
#include <stdio.h> #include <string.h> #include <sqlca.h> #include <sql2oci.h> /* The header file generated by processing object type 'aq.Message_typ': */ #include "pceg.h" void sql_error(msg) char *msg; { EXEC SQL WHENEVER SQLERROR CONTINUE; printf("%s\n", msg); printf("\n% .800s \n", sqlca.sqlerrm.sqlerrmc); EXEC SQL ROLLBACK WORK RELEASE; exit(1); } main() { Message_typ *message = (Message_typ*)0; /* payload */ message_type_ind *imsg; /*payload indicator*/ char user[60]="aq/AQ"; /* user logon password */ char subject[30]; /* components of the */ char txt[80]; /* payload type */ /* ENQUEUE and DEQUEUE to an OBJECT QUEUE */ /* Connect to database: */ EXEC SQL CONNECT :user; /* On an oracle error print the error number :*/ EXEC SQL WHENEVER SQLERROR DO sql_error("Oracle Error :"); /* Allocate memory for the host variable from the object cache : */ EXEC SQL ALLOCATE :message; /* ENQUEUE */ strcpy(subject, "NORMAL ENQUEUE"); strcpy(txt, "The Enqueue was done through PLSQL embedded in PROC"); /* Initialize the components of message : */ EXEC SQL OBJECT SET subject, text OF :message TO :subject, :txt; /* Embedded PLSQL call to the AQ enqueue procedure : */ EXEC SQL EXECUTE DECLARE message_properties dbms_aq.message_properties_t; enqueue_options dbms_aq.enqueue_options_t; msgid RAW(16); BEGIN /* Bind the host variable 'message' to the payload: */ dbms_aq.enqueue(queue_name => 'msg_queue', message_properties => message_properties, enqueue_options => enqueue_options, payload => :message:imsg, /* indicator must be specified */ msgid => msgid); END; END-EXEC; /* Commit work */ EXEC SQL COMMIT; printf("Enqueued Message \n"); printf("Subject :%s\n",subject); printf("Text :%s\n",txt); /* Dequeue */ /* Embedded PLSQL call to the AQ dequeue procedure : */ EXEC SQL EXECUTE DECLARE message_properties dbms_aq.message_properties_t; dequeue_options dbms_aq.dequeue_options_t; msgid RAW(16); BEGIN /* Return the payload into the host variable 'message': */ dbms_aq.dequeue(queue_name => 'msg_queue', message_properties => message_properties, dequeue_options => dequeue_options, payload => :message, msgid => msgid); END; END-EXEC; /* Commit work :*/ EXEC SQL COMMIT; /* Extract the components of message: */ EXEC SQL OBJECT GET SUBJECT,TEXT FROM :message INTO :subject,:txt; printf("Dequeued Message \n"); printf("Subject :%s\n",subject); printf("Text :%s\n",txt); }
This section provides an example that enqueues and dequeues RAW type messages using Pro*C/C++.
Example D-2 Enqueuing and Dequeuing RAW Type Messages (Pro*C/C++ )
#include <stdio.h> #include <string.h> #include <sqlca.h> #include <sql2oci.h> void sql_error(msg) char *msg; { EXEC SQL WHENEVER SQLERROR CONTINUE; printf("%s\n", msg); printf("\n% .800s \n", sqlca.sqlerrm.sqlerrmc); EXEC SQL ROLLBACK WORK RELEASE; exit(1); } main() { OCIEnv *oeh; /* OCI Env handle */ OCIError *err; /* OCI Err handle */ OCIRaw *message= (OCIRaw*)0; /* payload */ ub1 message_txt[100]; /* data for payload */ char user[60]="aq/AQ"; /* user logon password */ int status; /* returns status of the OCI call */ /* Enqueue and dequeue to a RAW queue */ /* Connect to database: */ EXEC SQL CONNECT :user; /* On an oracle error print the error number: */ EXEC SQL WHENEVER SQLERROR DO sql_error("Oracle Error :"); /* Get the OCI Env handle: */ if (SQLEnvGet(SQL_SINGLE_RCTX, &oeh) != OCI_SUCCESS) { printf(" error in SQLEnvGet \n"); exit(1); } /* Get the OCI Error handle: */ if (status = OCIHandleAlloc((dvoid *)oeh, (dvoid **)&err, (ub4)OCI_HTYPE_ERROR, (ub4)0, (dvoid **)0)) { printf(" error in OCIHandleAlloc %d \n", status); exit(1); } /* Enqueue */ /* The bytes to be put into the raw payload:*/ strcpy(message_txt, "Enqueue to a Raw payload queue "); /* Assign bytes to the OCIRaw pointer : Memory must be allocated explicitly to OCIRaw*: */ if (status=OCIRawAssignBytes(oeh, err, message_txt, 100, &message)) { printf(" error in OCIRawAssignBytes %d \n", status); exit(1); } /* Embedded PLSQL call to the AQ enqueue procedure : */ EXEC SQL EXECUTE DECLARE message_properties dbms_aq.message_properties_t; enqueue_options dbms_aq.enqueue_options_t; msgid RAW(16); BEGIN /* Bind the host variable message to the raw payload: */ dbms_aq.enqueue(queue_name => 'raw_msg_queue', message_properties => message_properties, enqueue_options => enqueue_options, payload => :message, msgid => msgid); END; END-EXEC; /* Commit work: */ EXEC SQL COMMIT; /* Dequeue */ /* Embedded PLSQL call to the AQ dequeue procedure :*/ EXEC SQL EXECUTE DECLARE message_properties dbms_aq.message_properties_t; dequeue_options dbms_aq.dequeue_options_t; msgid RAW(16); BEGIN /* Return the raw payload into the host variable 'message':*/ dbms_aq.dequeue(queue_name => 'raw_msg_queue', message_properties => message_properties, dequeue_options => dequeue_options, payload => :message, msgid => msgid); END; END-EXEC; /* Commit work: */ EXEC SQL COMMIT; }
This section provides an example that enqueues and dequeues messages by correlation and message ID.
Example D-3 Enqueuing and Dequeuing by Correlation and Message ID (Pro*C/C++)
#include <stdio.h> #include <string.h> #include <sqlca.h> #include <sql2oci.h> /* The header file generated by processing object type 'aq.Message_typ': */ #include "pceg.h" void sql_error(msg) char *msg; { EXEC SQL WHENEVER SQLERROR CONTINUE; printf("%s\n", msg); printf("\n% .800s \n", sqlca.sqlerrm.sqlerrmc); EXEC SQL ROLLBACK WORK RELEASE; exit(1); } main() { OCIEnv *oeh; /* OCI Env Handle */ OCIError *err; /* OCI Error Handle */ Message_typ *message = (Message_typ*)0; /* queue payload */ message_type_ind *imsg; /*payload indicator*/ OCIRaw *msgid = (OCIRaw*)0; /* message id */ ub1 msgmem[16]=""; /* memory for msgid */ char user[60]="aq/AQ"; /* user login password */ char subject[30]; /* components of */ char txt[80]; /* Message_typ */ char correlation1[30]; /* message correlation */ char correlation2[30]; int status; /* code returned by the OCI calls */ /* Dequeue by correlation and msgid */ /* Connect to the database: */ EXEC SQL CONNECT :user; EXEC SQL WHENEVER SQLERROR DO sql_error("Oracle Error :"); /* Allocate space in the object cache for the host variable: */ EXEC SQL ALLOCATE :message; /* Get the OCI Env handle: */ if (SQLEnvGet(SQL_SINGLE_RCTX, &oeh) != OCI_SUCCESS) { printf(" error in SQLEnvGet \n"); exit(1); } /* Get the OCI Error handle: */ if (status = OCIHandleAlloc((dvoid *)oeh, (dvoid **)&err, (ub4)OCI_HTYPE_ERROR, (ub4)0, (dvoid **)0)) { printf(" error in OCIHandleAlloc %d \n", status); exit(1); } /* Assign memory for msgid: Memory must be allocated explicitly to OCIRaw*: */ if (status=OCIRawAssignBytes(oeh, err, msgmem, 16, &msgid)) { printf(" error in OCIRawAssignBytes %d \n", status); exit(1); } /* First enqueue */ strcpy(correlation1, "1st message"); strcpy(subject, "NORMAL ENQUEUE1"); strcpy(txt, "The Enqueue was done through PLSQL embedded in PROC"); /* Initialize the components of message: */ EXEC SQL OJECT SET subject, text OF :message TO :subject, :txt; /* Embedded PLSQL call to the AQ enqueue procedure: */ EXEC SQL EXECUTE DECLARE message_properties dbms_aq.message_properties_t; enqueue_options dbms_aq.enqueue_options_t; BEGIN /* Bind the host variable 'correlation1': to message correlation*/ message_properties.correlation := :correlation1; /* Bind the host variable 'message' to payload and return message ID into host variable 'msgid': */ dbms_aq.enqueue(queue_name => 'msg_queue', message_properties => message_properties, enqueue_options => enqueue_options, payload => :message:imsg, /* indicator must be specified */ msgid => :msgid); END; END-EXEC; /* Commit work: */ EXEC SQL COMMIT; printf("Enqueued Message \n"); printf("Subject :%s\n",subject); printf("Text :%s\n",txt); /* Second enqueue */ strcpy(correlation2, "2nd message"); strcpy(subject, "NORMAL ENQUEUE2"); strcpy(txt, "The Enqueue was done through PLSQL embedded in PROC"); /* Initialize the components of message: */ EXEC SQL OBJECT SET subject, text OF :messsage TO :subject,:txt; /* Embedded PLSQL call to the AQ enqueue procedure: */ EXEC SQL EXECUTE DECLARE message_properties dbms_aq.message_properties_t; enqueue_options dbms_aq.enqueue_options_t; msgid RAW(16); BEGIN /* Bind the host variable 'correlation2': to message correlaiton */ message_properties.correlation := :correlation2; /* Bind the host variable 'message': to payload */ dbms_aq.enqueue(queue_name => 'msg_queue', message_properties => message_properties, enqueue_options => enqueue_options, payload => :message, msgid => msgid); END; END-EXEC; /* Commit work: */ EXEC SQL COMMIT; printf("Enqueued Message \n"); printf("Subject :%s\n",subject); printf("Text :%s\n",txt); /* First dequeue - by correlation */ EXEC SQL EXECUTE DECLARE message_properties dbms_aq.message_properties_t; dequeue_options dbms_aq.dequeue_options_t; msgid RAW(16); BEGIN /* Dequeue by correlation in host variable 'correlation2': */ dequeue_options.correlation := :correlation2; /* Return the payload into host variable 'message': */ dbms_aq.dequeue(queue_name => 'msg_queue', message_properties => message_properties, dequeue_options => dequeue_options, payload => :message, msgid => msgid); END; END-EXEC; /* Commit work : */ EXEC SQL COMMIT; /* Extract the values of the components of message: */ EXEC SQL OBJECT GET subject, text FROM :message INTO :subject,:txt; printf("Dequeued Message \n"); printf("Subject :%s\n",subject); printf("Text :%s\n",txt); /* SECOND DEQUEUE - by MSGID */ EXEC SQL EXECUTE DECLARE message_properties dbms_aq.message_properties_t; dequeue_options dbms_aq.dequeue_options_t; msgid RAW(16); BEGIN /* Dequeue by msgid in host variable 'msgid': */ dequeue_options.msgid := :msgid; /* Return the payload into host variable 'message': */ dbms_aq.dequeue(queue_name => 'msg_queue', message_properties => message_properties, dequeue_options => dequeue_options, payload => :message, msgid => msgid); END; END-EXEC; /* Commit work: */ EXEC SQL COMMIT; }