/****************************************************************************
** (c) Copyright IBM Corp. 2007 All rights reserved.
** 
** The following sample of source code ("Sample") is owned by International 
** Business Machines Corporation or one of its subsidiaries ("IBM") and is 
** copyrighted and licensed, not sold. You may use, copy, modify, and 
** distribute the Sample in any form without payment to IBM, for the purpose of 
** assisting you in the development of your applications.
** 
** The Sample code is provided to you on an "AS IS" basis, without warranty of 
** any kind. IBM HEREBY EXPRESSLY DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR 
** IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
** MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. Some jurisdictions do 
** not allow for the exclusion or limitation of implied warranties, so the above 
** limitations or exclusions may not apply to you. IBM shall not be liable for 
** any damages you suffer as a result of using, copying, modifying or 
** distributing the Sample, even if IBM has been advised of the possibility of 
** such damages.
*****************************************************************************
**
** SOURCE FILE NAME: tbtrig.sqc
**
** SAMPLE: How to use a trigger on a table
**
** SQL STATEMENTS USED:
**         DECLARE CURSOR
**         SELECT
**         OPEN
**         FETCH
**         CLOSE
**         CREATE TABLE
**         EXECUTE IMMEDIATE
**         PREPARE
**         DROP
**         CREATE TRIGGER
**         INSERT
**         DELETE
**         UPDATE
**
**                           
*****************************************************************************
**
** For more information on the sample programs, see the README file.
**
** For information on developing embedded SQL applications see the Developing Embedded SQL Applications book.
**
** For information on using SQL statements, see the SQL Reference.
**
** For the latest information on programming, building, and running DB2
** applications, visit the DB2 Information Center:
**     http://publib.boulder.ibm.com/infocenter/db2luw/v9r7/index.jsp
****************************************************************************/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sqlenv.h>
#include <sqlutil.h>
#include "utilemb.h"

int TbBeforeInsertTriggerUse(void);
int TbAfterInsertTriggerUse(void);
int TbBeforeDeleteTriggerUse(void);
int TbBeforeUpdateTriggerUse(void);
int TbAfterUpdateTriggerUse(void);

/* support functions */
int StaffTbContentDisplay(void);
int StaffStatsTbCreate(void);
int StaffStatsTbContentDisplay(void);
int StaffStatsTbDrop(void);
int SalaryStatusTbCreate(void);
int SalaryStatusTbContentDisplay(void);
int SalaryStatusTbDrop(void);
int SalaryHistoryTbCreate(void);
int SalaryHistoryTbContentDisplay(void);
int SalaryHistoryTbDrop(void);

EXEC SQL BEGIN DECLARE SECTION;
  char dbAlias[15];
  char user[15];
  char pswd[15];
  short id;
  char name[10];
  short dept;
  char job[10];
  short jobInd;
  short years;
  short yearsInd;
  double salary;
  double comm;
  short commInd;
  short nbemp;
  char emp_name[10];
  double sal;
  char status[16];
  char employee_name[10];
  double salary_record;
  char change_date[15];
  char strStmt[512];
EXEC SQL END DECLARE SECTION;

int main(int argc, char *argv[])
{
  int rc = 0;
  char dbAlias[SQL_ALIAS_SZ + 1];
  char user[USERID_SZ + 1];
  char pswd[PSWD_SZ + 1];

  /* check the command line arguments */
  rc = CmdLineArgsCheck1(argc, argv, dbAlias, user, pswd);
  if (rc != 0)
  {
    return rc;
  }

  printf("\nTHIS SAMPLE SHOWS HOW TO USE TRIGGERS.\n");

  /* connect to database */
  rc = DbConn(dbAlias, user, pswd);
  if (rc != 0)
  {
    return rc;
  }

  rc = TbBeforeInsertTriggerUse();
  rc = TbAfterInsertTriggerUse();
  rc = TbBeforeDeleteTriggerUse();
  rc = TbBeforeUpdateTriggerUse();
  rc = TbAfterUpdateTriggerUse();

  /* disconnect from the database */
  rc = DbDisconn(dbAlias);
  if (rc != 0)
  {
    return rc;
  }

  return 0;
} /* main */

int StaffTbContentDisplay(void)
{
  struct sqlca sqlca;

  printf("\n  Select * from staff where id <= 50\n");
  printf("    ID  NAME     DEPT JOB   YEARS SALARY   COMM\n");
  printf("    --- -------- ---- ----- ----- -------- --------\n");

  EXEC SQL DECLARE c1 CURSOR FOR
    SELECT * FROM staff WHERE id <= 50;

  EXEC SQL OPEN c1;
  EMB_SQL_CHECK("cursor -- open");

  EXEC SQL FETCH c1 INTO :id, :name, :dept, :job:jobInd, :years:yearsInd,
                         :salary, :comm:commInd;
  EMB_SQL_CHECK("cursor -- fetch");

  while (sqlca.sqlcode != 100)
  {
    printf("    %3d %-8.8s %4d", id, name, dept);
    if (jobInd >= 0)
    {
      printf(" %-5.5s", job);
    }
    else
    {
      printf("     -");
    }
    if (yearsInd >= 0)
    {
      printf(" %5d", years);
    }
    else
    {
      printf("     -");
    }
    printf(" %7.2f", salary);
    if (commInd >= 0)
    {
      printf(" %7.2f\n", comm);
    }
    else
    {
      printf("       -\n");
    }

    EXEC SQL FETCH c1 INTO :id, :name, :dept, :job:jobInd, :years:yearsInd,
                           :salary, :comm:commInd;
    EMB_SQL_CHECK("cursor -- fetch");
  }

  EXEC SQL CLOSE c1;
  EMB_SQL_CHECK("cursor -- close");

  return 0;
} /* StaffTbContentDisplay */

int StaffStatsTbCreate(void)
{
  struct sqlca sqlca;

  printf("\n  CREATE TABLE staff_stats(nbemp SMALLINT)\n");

  EXEC SQL CREATE TABLE staff_stats(nbemp SMALLINT);
  EMB_SQL_CHECK("table -- create");

  printf("\n  INSERT INTO staff_stats VALUES(SELECT COUNT(*) FROM staff)\n");
  strcpy(strStmt,
         "INSERT INTO staff_stats VALUES(SELECT COUNT(*) FROM staff) ");

  EXEC SQL EXECUTE IMMEDIATE :strStmt;
  EMB_SQL_CHECK("statement -- execute immediate");

  EXEC SQL COMMIT;
  EMB_SQL_CHECK("transaction -- commit");

  return 0;
} /* StaffStatsTbCreate */

int StaffStatsTbContentDisplay(void)
{
  struct sqlca sqlca;

  printf("\n  SELECT nbemp FROM staff_stats\n");
  printf("    NBEMP\n");
  printf("    -----\n");

  strcpy(strStmt, "SELECT * FROM staff_stats");

  EXEC SQL PREPARE stmt2 FROM :strStmt;
  EMB_SQL_CHECK("statement -- prepare");

  EXEC SQL DECLARE c2 CURSOR FOR stmt2;
  EMB_SQL_CHECK("cursor -- declare");

  EXEC SQL OPEN c2;
  EMB_SQL_CHECK("cursor -- open");

  EXEC SQL FETCH c2 INTO :nbemp;
  EMB_SQL_CHECK("cursor -- fetch");

  EXEC SQL CLOSE c2;

  printf("    %5d\n", nbemp);

  return 0;
} /* StaffStatsTbContentDisplay */

int StaffStatsTbDrop(void)
{
  struct sqlca sqlca;

  printf("\n  DROP TABLE staff_stats\n");

  EXEC SQL DROP TABLE staff_stats;
  EMB_SQL_CHECK("table -- drop");

  EXEC SQL COMMIT;
  EMB_SQL_CHECK("transaction -- commit");

  return 0;
} /* StaffStatsTbDrop */

int SalaryStatusTbCreate(void)
{
  struct sqlca sqlca;

  printf("\n  CREATE TABLE salary_status(emp_name VARCHAR(9),");
  printf("\n                             sal DECIMAL(7, 2),");
  printf("\n                             status CHAR(15))\n");

  EXEC SQL CREATE TABLE salary_status(emp_name VARCHAR(9),
                                      sal DECIMAL(7, 2),
                                      status CHAR(15));
  EMB_SQL_CHECK("table -- create");

  printf("\n  INSERT INTO salary_status\n");
  printf("  SELECT name, salary, 'Not Defined'\n");
  printf("  FROM staff\n");
  printf("  WHERE id <= 50\n");

  strcpy(strStmt, "INSERT INTO salary_status "
                  "SELECT name, salary, 'Not Defined' "
                  "FROM staff "
                  "WHERE id <= 50 ");

  EXEC SQL EXECUTE IMMEDIATE :strStmt;
  EMB_SQL_CHECK("statement -- execute immediate");

  EXEC SQL COMMIT;
  EMB_SQL_CHECK("transaction -- commit");

  return 0;
} /* SalaryStatusTbCreate */

int SalaryStatusTbContentDisplay(void)
{
  struct sqlca sqlca;

  printf("\n  Select * from salary_status\n");
  printf("    EMP_NAME   SALARY   STATUS          \n");
  printf("    ---------- -------- ----------------\n");

  strcpy(strStmt, "SELECT * FROM salary_status");

  EXEC SQL PREPARE stmt3 FROM :strStmt;
  EMB_SQL_CHECK("statement -- prepare");

  EXEC SQL DECLARE c3 CURSOR FOR stmt3;
  EMB_SQL_CHECK("cursor -- declare");

  EXEC SQL OPEN c3;
  EMB_SQL_CHECK("cursor -- open");

  EXEC SQL FETCH c3 INTO :emp_name, :sal, :status;
  EMB_SQL_CHECK("cursor -- fetch");

  while (sqlca.sqlcode != 100)
  {
    printf("    %-10s %7.2f %-15s\n", emp_name, sal, status);

    EXEC SQL FETCH c3 INTO :emp_name, :sal, :status;
    EMB_SQL_CHECK("cursor -- fetch");
  }
  EXEC SQL CLOSE c3;

  return 0;
} /* SalaryStatusTbContentDisplay */

int SalaryStatusTbDrop(void)
{
  struct sqlca sqlca;

  printf("\n  DROP TABLE salary_status\n");

  EXEC SQL DROP TABLE salary_status;
  EMB_SQL_CHECK("table -- drop");

  EXEC SQL COMMIT;
  EMB_SQL_CHECK("transaction -- commit");

  return 0;
} /* SalaryStatusTbDrop */

int SalaryHistoryTbCreate(void)
{
  struct sqlca sqlca;

  printf("\n  CREATE TABLE salary_history(employee_name VARCHAR(9),");
  printf("\n                              salary_record DECIMAL(7, 2),");
  printf("\n                              change_date DATE)\n");

  EXEC SQL CREATE TABLE salary_history(employee_name VARCHAR(9),
                                       salary_record DECIMAL(7, 2),
                                       change_date DATE);
  EMB_SQL_CHECK("table -- create");

  EXEC SQL COMMIT;
  EMB_SQL_CHECK("transaction -- commit");

  return 0;
} /* SalaryHistoryTbCreate */

int SalaryHistoryTbContentDisplay(void)
{
  struct sqlca sqlca;

  printf("\n  Select * from salary_history\n");
  printf("    EMPLOYEE_NAME  SALARY_RECORD  CHANGE_DATE\n");
  printf("    -------------- -------------- -----------\n");

  strcpy(strStmt, "SELECT * FROM salary_history");

  EXEC SQL PREPARE stmt4 FROM :strStmt;
  EMB_SQL_CHECK("statement -- prepare");

  EXEC SQL DECLARE c4 CURSOR FOR stmt4;
  EMB_SQL_CHECK("cursor -- declare");

  EXEC SQL OPEN c4;
  EMB_SQL_CHECK("cursor -- open");

  EXEC SQL FETCH c4 INTO :employee_name, :salary_record, :change_date;
  EMB_SQL_CHECK("cursor -- fetch");

  while (sqlca.sqlcode != 100)
  {
    printf("    %-14s %14.2f %-15s\n",
           employee_name, salary_record, change_date);

    EXEC SQL FETCH c4 INTO :employee_name, :salary_record, :change_date;
    EMB_SQL_CHECK("cursor -- fetch");
  }
  EXEC SQL CLOSE c4;

  return 0;
} /* SalaryHistoryTbContentDisplay */

int SalaryHistoryTbDrop(void)
{
  struct sqlca sqlca;

  printf("\n  DROP TABLE salary_history\n");

  EXEC SQL DROP TABLE salary_history;
  EMB_SQL_CHECK("table -- drop");

  EXEC SQL COMMIT;
  EMB_SQL_CHECK("transaction -- commit");

  return 0;
} /* SalaryHistoryTbDrop */

int TbBeforeInsertTriggerUse(void)
{
  int rc = 0;
  struct sqlca sqlca;

  printf("\n-----------------------------------------------------------");
  printf("\nUSE THE SQL STATEMENTS:\n");
  printf("  CREATE TRIGGER\n");
  printf("  COMMIT\n");
  printf("  INSERT\n");
  printf("  DROP TRIGGER\n");
  printf("TO SHOW A 'BEFORE INSERT' TRIGGER.\n");

  /* display initial table content */
  rc = StaffTbContentDisplay();

  printf("\n  CREATE TRIGGER min_sal"
         "\n    NO CASCADE BEFORE"
         "\n    INSERT ON staff"
         "\n    REFERENCING NEW AS newstaff"
         "\n    FOR EACH ROW"
         "\n    BEGIN ATOMIC"
         "\n      SET newstaff.salary ="
         "\n        CASE"
         "\n          WHEN newstaff.job = 'Mgr' AND "
                          "newstaff.salary < 17000.00"
         "\n            THEN 17000.00"
         "\n          WHEN newstaff.job = 'Sales' AND "
                          "newstaff.salary < 14000.00"
         "\n            THEN 14000.00"
         "\n          WHEN newstaff.job = 'Clerk' AND "
                          "newstaff.salary < 10000.00"
         "\n            THEN 10000.00"
         "\n          ELSE newstaff.salary"
         "\n        END;"
         "\n    END\n");

  EXEC SQL CREATE TRIGGER min_sal
    NO CASCADE BEFORE
    INSERT ON staff
    REFERENCING NEW AS newstaff
    FOR EACH ROW
    BEGIN ATOMIC
      SET newstaff.salary =
        CASE
          WHEN newstaff.job = 'Mgr' AND newstaff.salary < 17000.00
            THEN 17000.00
          WHEN newstaff.job = 'Sales' AND newstaff.salary < 14000.00
            THEN 14000.00
          WHEN newstaff.job = 'Clerk' AND newstaff.salary < 10000.00
            THEN 10000.00
          ELSE newstaff.salary
        END;
    END;
  EMB_SQL_CHECK("trigger -- create");

  EXEC SQL COMMIT;
  EMB_SQL_CHECK("create trigger -- commit");

  /* insert into the table using values */
  printf("\n  Invoke the statement\n");
  printf("    INSERT INTO staff(id, name, dept, job, salary)\n");
  printf("      VALUES(25, 'Pearce', 38, 'Clerk', 7217.50),\n");
  printf("            (35, 'Hachey', 38, 'Mgr', 21270.00),\n");
  printf("            (45, 'Wagland', 38, 'Sales', 11575.00)\n");

  EXEC SQL INSERT INTO staff(id, name, dept, job, salary)
    VALUES(25, 'Pearce', 38, 'Clerk', 7217.50),
          (35, 'Hachey', 38, 'Mgr', 21270.00),
          (45, 'Wagland', 38, 'Sales', 11575.00);
  EMB_SQL_CHECK("table -- insert using values");

  /* display final content of the table */
  rc = StaffTbContentDisplay();

  /* rollback transaction */
  printf("\n  Rollback the transaction.\n");

  EXEC SQL ROLLBACK;
  EMB_SQL_CHECK("transaction -- rollback");

  printf("\n  DROP TRIGGER min_sal\n");

  EXEC SQL DROP TRIGGER min_sal;
  EMB_SQL_CHECK("trigger -- drop");

  EXEC SQL COMMIT;
  EMB_SQL_CHECK("drop trigger -- commit");

  return 0;
} /* TbBeforeInsertTriggerUse */

int TbAfterInsertTriggerUse(void)
{
  int rc = 0;
  struct sqlca sqlca;

  printf("\n-----------------------------------------------------------");
  printf("\nUSE THE SQL STATEMENTS:\n");
  printf("  CREATE TRIGGER\n");
  printf("  COMMIT\n");
  printf("  INSERT\n");
  printf("  DROP TRIGGER\n");
  printf("TO SHOW AN 'AFTER INSERT' TRIGGER.\n");

  /* create staff_stats table */
  rc = StaffStatsTbCreate();
  if (rc != 0)
  {
    return rc;
  }

  /* display staff_stats table content */
  rc = StaffStatsTbContentDisplay();

  strcpy(strStmt, "CREATE TRIGGER new_hire AFTER"
                  "  INSERT ON staff "
                  "  FOR EACH ROW "
                  "  BEGIN ATOMIC "
                  "    UPDATE staff_stats SET nbemp = nbemp + 1; "
                  "  END");
  printf("\n  CREATE TRIGGER new_hire AFTER"
         "\n    INSERT ON staff"
         "\n    FOR EACH ROW"
         "\n    BEGIN ATOMIC"
         "\n      UPDATE staff_stats SET nbemp = nbemp + 1;"
         "\n    END\n");

  EXEC SQL EXECUTE IMMEDIATE :strStmt;
  EMB_SQL_CHECK("trigger -- create");

  EXEC SQL COMMIT;
  EMB_SQL_CHECK("create trigger -- commit");

  /* insert into the table using values */
  printf("\n  Invoke the statement\n");
  printf("    INSERT INTO staff(id, name, dept, job, salary)\n");
  printf("      VALUES(25, 'Pearce', 38, 'Clerk', 7217.50),\n");
  printf("            (35, 'Hachey', 38, 'Mgr', 21270.00),\n");
  printf("            (45, 'Wagland', 38, 'Sales', 11575.00)\n");

  EXEC SQL INSERT INTO staff(id, name, dept, job, salary)
    VALUES(25, 'Pearce', 38, 'Clerk', 7217.50),
          (35, 'Hachey', 38, 'Mgr', 21270.00),
          (45, 'Wagland', 38, 'Sales', 11575.00);
  EMB_SQL_CHECK("table -- insert using values");

  /* display staff_stats table content */
  rc = StaffStatsTbContentDisplay();

  /* rollback transaction */
  printf("\n  Rollback the transaction.\n");

  EXEC SQL ROLLBACK;
  EMB_SQL_CHECK("transaction -- rollback");

  strcpy(strStmt, "  DROP TRIGGER new_hire");
  printf("\n%s\n", strStmt);

  EXEC SQL EXECUTE IMMEDIATE :strStmt;
  EMB_SQL_CHECK("trigger -- drop");

  EXEC SQL COMMIT;
  EMB_SQL_CHECK("drop trigger -- commit");

  /* drop staff_stats table */
  rc = StaffStatsTbDrop();

  return 0;
} /* TbAfterInsertTriggerUse */

int TbBeforeDeleteTriggerUse(void)
{
  int rc = 0;
  struct sqlca sqlca;
  char sqlstate[5 + 1];
  char sqlerrmsg[70 + 1];

  printf("\n-----------------------------------------------------------");
  printf("\nUSE THE SQL STATEMENTS:\n");
  printf("  CREATE TRIGGER\n");
  printf("  COMMIT\n");
  printf("  DELETE\n");
  printf("  DROP TRIGGER\n");
  printf("TO SHOW A 'BEFORE DELETE' TRIGGER.\n");

  /* display initial content of the table */
  rc = StaffTbContentDisplay();

  printf("\n  CREATE TRIGGER do_not_delete_sales"
         "\n    NO CASCADE BEFORE"
         "\n    DELETE ON staff"
         "\n    REFERENCING OLD AS oldstaff"
         "\n    FOR EACH ROW"
         "\n    WHEN(oldstaff.job = 'Sales')"
         "\n    BEGIN ATOMIC"
         "\n      SIGNAL SQLSTATE '75000' "
         "('Sales can not be deleted now.');"
         "\n    END\n");

  EXEC SQL CREATE TRIGGER do_not_delete_sales
    NO CASCADE BEFORE
    DELETE ON staff
    REFERENCING OLD AS oldstaff
    FOR EACH ROW
    WHEN(oldstaff.job = 'Sales')
    BEGIN ATOMIC
      SIGNAL SQLSTATE '75000' ('Sales can not be deleted now.');
    END;
  EMB_SQL_CHECK("trigger -- create");

  EXEC SQL COMMIT;
  EMB_SQL_CHECK("create trigger -- commit");

  /* delete table */
  printf("\n  Invoke the statement\n");
  printf("    DELETE FROM staff WHERE id <= 50\n");

  EXEC SQL DELETE FROM staff WHERE id <= 50;

  if (sqlca.sqlcode == -438)
  {
    memcpy(sqlstate, sqlca.sqlstate, 5);
    sqlstate[5] = '\0';
    memcpy(sqlerrmsg, sqlca.sqlerrmc, sqlca.sqlerrml);
    sqlerrmsg[sqlca.sqlerrml] = '\0';

    printf("  SQL0438N %s SQLSTATE = %s\n", sqlerrmsg, sqlstate);
  }
  else
  {
    EMB_SQL_CHECK("table -- delete");
  }

  /* display final content of the table */
  rc = StaffTbContentDisplay();

  /* rollback transaction */
  printf("\n  Rollback the transaction.\n");

  EXEC SQL ROLLBACK;
  EMB_SQL_CHECK("transaction -- rollback");

  printf("\n  DROP TRIGGER do_not_delete_sales\n");

  EXEC SQL DROP TRIGGER do_not_delete_sales;
  EMB_SQL_CHECK("trigger -- drop");

  EXEC SQL COMMIT;
  EMB_SQL_CHECK("drop trigger -- commit");

  return 0;
} /* TbBeforeDeleteTriggerUse */

int TbBeforeUpdateTriggerUse(void)
{
  int rc = 0;
  struct sqlca sqlca;

  printf("\n-----------------------------------------------------------");
  printf("\nUSE THE SQL STATEMENTS:\n");
  printf("  CREATE TRIGGER\n");
  printf("  COMMIT\n");
  printf("  UPDATE\n");
  printf("  DROP TRIGGER\n");
  printf("TO SHOW A 'BEFORE UPDATE' TRIGGER.\n");

  /* create salary_status table */
  rc = SalaryStatusTbCreate();
  if (rc != 0)
  {
    return rc;
  }

  /* display salary_status table content */
  rc = SalaryStatusTbContentDisplay();

  strcpy(strStmt,
         "CREATE TRIGGER sal_status "
         "  NO CASCADE BEFORE "
         "  UPDATE OF sal "
         "  ON salary_status "
         "  REFERENCING NEW AS new OLD AS old "
         "  FOR EACH ROW "
         "  BEGIN ATOMIC "
         "    SET new.status = "
         "      CASE "
         "        WHEN new.sal < old.sal THEN 'Decreasing' "
         "        WHEN new.sal > old.sal THEN 'Increasing' "
         "      END;"
         "  END ");

  printf("\n  CREATE TRIGGER salary_status"
         "\n    NO CASCADE BEFORE"
         "\n    UPDATE OF sal"
         "\n    ON salary_status"
         "\n    REFERENCING NEW AS new OLD AS old"
         "\n    FOR EACH ROW"
         "\n    BEGIN ATOMIC"
         "\n      SET new.status ="
         "\n        CASE"
         "\n          WHEN new.sal < old.sal THEN 'Decreasing'"
         "\n          WHEN new.sal > old.sal THEN 'Increasing'"
         "\n        END;"
         "\n    END\n");

  EXEC SQL EXECUTE IMMEDIATE :strStmt;
  EMB_SQL_CHECK("trigger -- create");

  EXEC SQL COMMIT;
  EMB_SQL_CHECK("create trigger -- commit");

  /* update table */
  printf("\n  Invoke the statement\n");
  printf("    UPDATE salary_status SET sal = 18000.00\n");
  strcpy(strStmt, "UPDATE salary_status SET sal = 18000.00");

  EXEC SQL EXECUTE IMMEDIATE :strStmt;
  EMB_SQL_CHECK("table -- update");

  /* display salary_status table content */
  rc = SalaryStatusTbContentDisplay();

  /* rollback transaction */
  printf("\n  Rollback the transaction.\n");

  EXEC SQL ROLLBACK;
  EMB_SQL_CHECK("transaction -- rollback");

  strcpy(strStmt, "  DROP TRIGGER sal_status");
  printf("\n%s\n", strStmt);

  EXEC SQL EXECUTE IMMEDIATE :strStmt;
  EMB_SQL_CHECK("trigger -- drop");

  EXEC SQL COMMIT;
  EMB_SQL_CHECK("drop trigger -- commit");

  /* drop salary_status table */
  rc = SalaryStatusTbDrop();

  return 0;
} /* TbBeforeUpdateTriggerUse */

int TbAfterUpdateTriggerUse(void)
{
  int rc = 0;
  struct sqlca sqlca;

  printf("\n-----------------------------------------------------------");
  printf("\nUSE THE SQL STATEMENTS:\n");
  printf("  CREATE TRIGGER\n");
  printf("  COMMIT\n");
  printf("  UPDATE\n");
  printf("  DROP TRIGGER\n");
  printf("TO SHOW AN 'AFTER UPDATE' TRIGGER.\n");

  /* create salary_history table */
  rc = SalaryHistoryTbCreate();
  if (rc != 0)
  {
    return rc;
  }

  /* display salary_history table content */
  rc = SalaryHistoryTbContentDisplay();

  strcpy(strStmt,
         "CREATE TRIGGER sal_history "
         "  AFTER "
         "  UPDATE OF salary ON staff "
         "  REFERENCING NEW AS newstaff "
         "  FOR EACH ROW "
         "  BEGIN ATOMIC "
         "    INSERT INTO salary_history "
         "      VALUES(newstaff.name, newstaff.salary, CURRENT DATE);"
         "  END ");

  printf("\n  CREATE TRIGGER sal_history"
         "\n    AFTER"
         "\n    UPDATE OF salary ON staff"
         "\n    REFERENCING NEW AS newstaff"
         "\n    FOR EACH ROW"
         "\n    BEGIN ATOMIC"
         "\n      INSERT INTO salary_history"
         "\n        VALUES(newstaff.name, newstaff.salary, CURRENT DATE);"
         "\n    END\n");

  EXEC SQL EXECUTE IMMEDIATE :strStmt;
  EMB_SQL_CHECK("trigger -- create");

  EXEC SQL COMMIT;
  EMB_SQL_CHECK("create trigger -- commit");

  /* update table */
  printf("\n  Invoke the statement\n");
  printf("    UPDATE staff SET salary = 20000.00 WHERE name = 'Sanders'\n");

  EXEC SQL UPDATE staff SET salary = 20000.00 WHERE name = 'Sanders';
  EMB_SQL_CHECK("table -- update");

  printf("\n  Invoke the statement\n");
  printf("    UPDATE staff SET salary = 21000.00 WHERE name = 'Sanders'\n");

  EXEC SQL UPDATE staff SET salary = 21000.00 WHERE name = 'Sanders';
  EMB_SQL_CHECK("table -- update");

  printf("\n  Invoke the statement\n");
  printf("    UPDATE staff SET salary = 23000.00 WHERE name = 'Sanders'\n");

  EXEC SQL UPDATE staff SET salary = 23000.00 WHERE name = 'Sanders';
  EMB_SQL_CHECK("table -- update");

  printf("\n  Invoke the statement\n");
  printf("    UPDATE staff SET salary = 20000.00 WHERE name = 'Hanes'\n");

  EXEC SQL UPDATE staff SET salary = 20000.00 WHERE name = 'Hanes';
  EMB_SQL_CHECK("table -- update");

  printf("\n  Invoke the statement\n");
  printf("    UPDATE staff SET salary = 21000.00 WHERE name = 'Hanes'\n");

  EXEC SQL UPDATE staff SET salary = 21000.00 WHERE name = 'Hanes';
  EMB_SQL_CHECK("table -- update")

  /* display salary_history table content */
  rc = SalaryHistoryTbContentDisplay();

  /* rollback transaction */
  printf("\n  Rollback the transaction.\n");

  EXEC SQL ROLLBACK;
  EMB_SQL_CHECK("transaction -- rollback");

  strcpy(strStmt, "  DROP TRIGGER sal_history");
  printf("\n%s\n", strStmt);

  EXEC SQL EXECUTE IMMEDIATE :strStmt;
  EMB_SQL_CHECK("trigger -- drop");

  EXEC SQL COMMIT;
  EMB_SQL_CHECK("drop trigger -- commit");

  /* drop salary_history table */
  rc = SalaryHistoryTbDrop();

  return 0;
} /* TbAfterUpdateTriggerUse */