/****************************************************************************
** (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: tbmod.sqc 
**    
** SAMPLE: How to modify table data 
**           
** SQL STATEMENTS USED:
**         DELETE 
**         DECLARE CURSOR 
**         OPEN
**         FETCH
**         CLOSE
**         INSERT
**         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 information on DB2 APIs, see the Administrative API 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"

/* types of insert */
int InsertUsingValues(void);
int InsertUsingFullselect(void);

/* types of update */
int UpdateWithoutSubqueries(void);
int UpdateUsingSubqueryInSetClause(void);
int UpdateUsingSubqueryInWhereClause(void);
int UpdateUsingCorrelatedSubqueryInSetClause(void);
int UpdateUsingCorrelatedSubqueryInWhereClause(void);
int PositionedUpdateWithoutSubqueries(void);
int PositionedUpdateUsingSubqueryInSetClause(void);
int PositionedUpdateUsingCorrelatedSubqueryInSetClause(void);

/* types of delete */
int DeleteWithoutSubqueries(void);
int DeleteUsingSubqueryInWhereClause(void);
int DeleteUsingCorrelatedSubqueryInWhereClause(void);
int PositionedDelete(void);

/* support functions */
int StaffTbContentDisplay(void);

EXEC SQL BEGIN DECLARE SECTION;
  short id;
  char name[10];
  short dept;
  char job[10];
  short jobInd;
  short years;
  short yearsInd;
  double salary;
  double comm;
  short commInd;
  char empno[7];
  char workdept[8];
EXEC SQL END DECLARE SECTION;

int main(int argc, char *argv[])
{
  int rc = 0;
  struct sqlca sqlca;

  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 MODIFY TABLE DATA.\n");

  printf("\n  THERE ARE THREE WAYS TO MODIFY TABLE DATA:\n");
  printf("    INSERT ROW(S)\n");
  printf("    UPDATE ROW(S)\n");
  printf("    DELETE ROW(S)\n");
  printf("  THIS SAMPLE SHOWS ALL TYPES OF INSERT, UPDATE AND DELETE\n");
  printf("  INVOKING THE STATEMENTS STATICALLY, WITHOUT PARAMETERS.\n");
  printf("\n  HOWEVER, FOR EVERY TYPE, ALL THE METHODS\n");
  printf("  DESCRIBED IN THE SAMPLE dbuse CAN BE USED, AS FOLLOWS:\n");
  printf("    StaticStmtInvoke\n");
  printf("    StaticStmtWithHostVarsInvoke\n");
  printf("    DynamicStmtEXECUTE_IMMEDIATE\n");
  printf("    DynamicStmtEXECUTE\n");
  printf("    DynamicStmtWithMarkersEXECUTEusingHostVars\n");
  printf("    DynamicStmtWithMarkersEXECUTEusingSQLDA\n");
  printf("    CompoundStmtInvoke\n");

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

  /* create table for sample */
  /*rc = CreateTableForSample();*/

  /* types of Insert */
  rc = InsertUsingValues();
  rc = InsertUsingFullselect();

  /* types of Update */
  rc = UpdateWithoutSubqueries();
  rc = UpdateUsingSubqueryInSetClause();
  rc = UpdateUsingSubqueryInWhereClause();
  rc = UpdateUsingCorrelatedSubqueryInSetClause();
  rc = UpdateUsingCorrelatedSubqueryInWhereClause();
  rc = PositionedUpdateWithoutSubqueries();
  rc = PositionedUpdateUsingSubqueryInSetClause();
  rc = PositionedUpdateUsingCorrelatedSubqueryInSetClause();

  /* types of Delete */
  rc = DeleteWithoutSubqueries();
  rc = DeleteUsingSubqueryInWhereClause();
  rc = DeleteUsingCorrelatedSubqueryInWhereClause();
  rc = PositionedDelete();

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

  return 0;
} /* end main */

int StaffTbContentDisplay(void)
{
  struct sqlca sqlca;

  printf("\n  SELECT * FROM staff WHERE id >= 310\n");
  printf("    ID  NAME     DEPT JOB   YEARS SALARY   COMM\n");
  printf("    --- -------- ---- ----- ----- -------- -------\n");

  EXEC SQL DECLARE posCur0 CURSOR FOR SELECT * FROM staff WHERE id >= 310;

  EXEC SQL OPEN posCur0;
  EMB_SQL_CHECK("cursor -- open");

  EXEC SQL FETCH posCur0 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", comm);
    }
    else
    {
      printf("       -");
    }
    printf("\n");

    EXEC SQL FETCH posCur0 INTO :id, :name, :dept, :job:jobInd,
                                :years:yearsInd, :salary, :comm:commInd;
    EMB_SQL_CHECK("cursor -- fetch");
  }

  EXEC SQL CLOSE posCur0;
  EMB_SQL_CHECK("cursor -- close");

  return 0;
} /* StaffTbContentDisplay */

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

  printf("\n-----------------------------------------------------------");
  printf("\nUSE THE SQL STATEMENT:\n");
  printf("  INSERT\n");
  printf("TO INSERT DATA INTO A TABLE USING VALUES.\n");

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

  /* insert into table using values */
  printf("\n  Invoke the statement\n");
  printf("    INSERT INTO staff(id, name, dept, job, salary)\n");
  printf("      VALUES(380, 'Pearce', 38, 'Clerk', 13217.50),\n");
  printf("            (390, 'Hachey', 38, 'Mgr', 21270.00),\n");
  printf("            (400, 'Wagland', 38, 'Clerk', 14575.00)\n");

  EXEC SQL INSERT INTO staff(id, name, dept, job, salary)
    VALUES(380, 'Pearce', 38, 'Clerk', 13217.50),
          (390, 'Hachey', 38, 'Mgr', 21270.00),
          (400, 'Wagland', 38, 'Clerk', 14575.00);
  EMB_SQL_CHECK("table -- insert using values");

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

  /* rollback the transaction */
  TransRollback();

  return 0;
} /* InsertUsingValues */

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

  printf("\n-----------------------------------------------------------");
  printf("\nUSE THE SQL STATEMENT:\n");
  printf("  INSERT\n");
  printf("TO INSERT DATA INTO A TABLE USING FULLSELECT.\n");

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

  /* insert into the table using fullselect */
  printf("\n  Invoke the statement\n");
  printf("    INSERT INTO staff(id, name, dept, salary)\n");
  printf("      SELECT INTEGER(empno)+100, lastname, 77, salary\n");
  printf("        FROM employee\n");
  printf("        WHERE INTEGER(empno) >= 310\n");
  printf("        AND INTEGER(empno) <= 340\n");

  EXEC SQL INSERT INTO staff(id, name, dept, salary)
    SELECT INTEGER(empno) + 100, lastname, 77, salary
      FROM employee
      WHERE INTEGER(empno) >= 310
      AND INTEGER(empno) <= 340;
  EMB_SQL_CHECK("table -- insert using fullselect");

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

  /* rollback the transaction */
  TransRollback();

  return 0;
} /* InsertUsingFullselect */

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

  printf("\n-----------------------------------------------------------");
  printf("\nUSE THE SQL STATEMENT:\n");
  printf("  UPDATE\n");
  printf("TO UPDATE TABLE DATA.\n");

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

  /* update the table */
  printf("\n  Invoke the statement\n");
  printf("    UPDATE staff SET salary = salary + 1000\n");
  printf("      WHERE id >= 310 AND dept = 84\n");

  EXEC SQL UPDATE staff SET salary = salary + 1000
    WHERE id >= 310 AND dept = 84;
  EMB_SQL_CHECK("table -- update");

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

  /* rollback the transaction */
  TransRollback();

  return 0;
} /* UpdateWithoutSubqueries */

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

  printf("\n-----------------------------------------------------------");
  printf("\nUSE THE SQL STATEMENT:\n");
  printf("  UPDATE\n");
  printf("TO UPDATE TABLE DATA\n");
  printf("USING SUBQUERY IN 'SET' CLAUSE.\n");

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

  /* table -- update using subquery in SET clause */
  printf("\n  Invoke the statement\n");
  printf("    UPDATE staff SET salary = (SELECT MIN(salary)\n");
  printf("                                 FROM staff\n");
  printf("                                 WHERE id >= 310)\n");
  printf("      WHERE id = 350\n");

  EXEC SQL UPDATE staff SET salary = (SELECT MIN(salary)
                                        FROM staff
                                        WHERE id >= 310)
    WHERE id = 350;
  EMB_SQL_CHECK("table -- update using subquery in SET clause");

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

  /* rollback the transaction */
  TransRollback();

  return 0;
} /* UpdateUsingSubqueryInSetClause */

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

  printf("\n-----------------------------------------------------------");
  printf("\nUSE THE SQL STATEMENT:\n");
  printf("  UPDATE\n");
  printf("TO UPDATE TABLE DATA\n");
  printf("USING SUBQUERY IN 'WHERE' CLAUSE.\n");

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

  /* update the table using subquery in WHERE clause */
  printf("\n  Invoke the statement\n");
  printf("    UPDATE staff SET comm = 250.00\n");
  printf("      WHERE dept = 84 AND\n");
  printf("            salary < (SELECT AVG(salary)\n");
  printf("                        FROM staff\n");
  printf("                        WHERE id >= 310 AND dept = 84)\n");

  EXEC SQL UPDATE staff SET comm = 250.00
    WHERE dept = 84 AND
          salary < (SELECT AVG(salary)
                      FROM staff
                      WHERE id >= 310 AND dept = 84);
  EMB_SQL_CHECK("table -- update using subquery in WHERE clause");

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

  /* rollback the transaction */
  TransRollback();

  return 0;
} /* UpdateUsingSubqueryInWhereClause */

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

  printf("\n-----------------------------------------------------------");
  printf("\nUSE THE SQL STATEMENT:\n");
  printf("  UPDATE\n");
  printf("TO UPDATE TABLE DATA\n");
  printf("USING CORRELATED SUBQUERY IN 'SET' CLAUSE.\n");

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

  /* update the table using correlated subquery in SET clause */
  printf("\n  Invoke the statement\n");
  printf("    UPDATE staff s1\n");
  printf("      SET comm = 0.01 * (SELECT MIN(salary)\n");
  printf("                           FROM staff s2\n");
  printf("                           WHERE id >= 310 AND\n");
  printf("                                 s2.dept = s1.dept)\n");
  printf("      WHERE id >= 340\n");

  EXEC SQL UPDATE staff s1
    SET comm = 0.01 * (SELECT MIN(salary)
                         FROM staff s2
                         WHERE id >= 310 AND
                               s2.dept = s1.dept)
    WHERE id >= 340;
  EMB_SQL_CHECK("table -- update using correl. subquery in SET clause");

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

  /* rollback the transaction */
  TransRollback();

  return 0;
} /* UpdateUsingCorrelatedSubqueryInSetClause */

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

  printf("\n-----------------------------------------------------------");
  printf("\nUSE THE SQL STATEMENT:\n");
  printf("  UPDATE\n");
  printf("TO UPDATE TABLE DATA\n");
  printf("USING CORRELATED SUBQUERY IN 'WHERE' CLAUSE.\n");

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

  /* update the table using correlated subquery in WHERE clause */
  printf("\n  Invoke the statement\n");
  printf("    UPDATE staff s1 SET comm = 700\n");
  printf("      WHERE id >= 340 AND\n");
  printf("            salary < (SELECT AVG(salary)\n");
  printf("                        FROM staff s2\n");
  printf("                        WHERE id >= 310 AND\n");
  printf("                              s2.dept = s1.dept)\n");

  EXEC SQL UPDATE staff s1 SET comm = 700
    WHERE id >= 340 AND
          salary < (SELECT AVG(salary)
                      FROM staff s2
                      WHERE id >= 310 AND
                            s2.dept = s1.dept);
  EMB_SQL_CHECK("table -- update using correl. subquery in WHERE clause");

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

  /* rollback the transaction */
  TransRollback();

  return 0;
} /* UpdateUsingCorrelatedSubqueryInWhereClause */

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

  printf("\n-----------------------------------------------------------");
  printf("\nUSE THE SQL STATEMENTS:\n");
  printf("  DECLARE CURSOR\n");
  printf("  OPEN\n");
  printf("  FETCH\n");
  printf("  UPDATE\n");
  printf("  CLOSE\n");
  printf("TO PERFORM POSITIONED UPDATE ON A ROW.\n");

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

  printf("\n  Invoke the statements:\n");
  printf("    DECLARE posCur1 CURSOR FOR\n");
  printf("      SELECT name, dept FROM staff WHERE id >= 310");
  printf(" FOR UPDATE OF comm\n");
  printf("    OPEN posCur1\n");
  printf("    FETCH posCur1 INTO :name, :dept\n");
  printf("    while (successful fetch)\n");
  printf("    {\n");
  printf("      if (dept != 84)\n");
  printf("      {\n");
  printf("        UPDATE staff SET comm = NULL");
  printf(" WHERE CURRENT OF posCur1\n");
  printf("      }\n");
  printf("      FETCH posCur1 INTO :name, :dept\n");
  printf("    }\n");

  /* declare cursor */
  EXEC SQL DECLARE posCur1 CURSOR FOR
    SELECT name, dept FROM staff WHERE id >= 310 FOR UPDATE OF comm;

  /* open cursor */
  EXEC SQL OPEN posCur1;
  EMB_SQL_CHECK("cursor -- open");

  /* fetch cursor */
  EXEC SQL FETCH posCur1 INTO :name, :dept;
  EMB_SQL_CHECK("cursor -- fetch");

  while (sqlca.sqlcode != 100)
  {
    if (dept != 84)
    {
      EXEC SQL UPDATE staff SET comm = NULL WHERE CURRENT OF posCur1;
      EMB_SQL_CHECK("table -- positioned update");
    }

    EXEC SQL FETCH posCur1 INTO :name, :dept;
    EMB_SQL_CHECK("cursor -- fetch");
  }

  /* close cursor */
  EXEC SQL CLOSE posCur1;
  EMB_SQL_CHECK("cursor -- close");

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

  /* rollback the transaction */
  TransRollback();

  return 0;
} /* PositionedUpdateWithoutSubqueries */

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

  printf("\n-----------------------------------------------------------");
  printf("\nUSE THE SQL STATEMENTS:\n");
  printf("  DECLARE CURSOR\n");
  printf("  OPEN\n");
  printf("  FETCH\n");
  printf("  UPDATE\n");
  printf("  CLOSE\n");
  printf("TO PERFORM POSITIONED UPDATE ON A ROW\n");
  printf("USING SUBQUERY IN 'SET' CLAUSE.\n");

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

  printf("\n  Invoke the statements:\n");
  printf("    DECLARE posCur2 CURSOR FOR\n");
  printf("      SELECT name, dept FROM staff WHERE id >= 310");
  printf(" FOR UPDATE OF comm\n");
  printf("    OPEN posCur2\n");
  printf("    FETCH posCur2 INTO :name, :dept\n");
  printf("    while (successful fetch)\n");
  printf("    {\n");
  printf("      if (dept != 84)\n");
  printf("      {\n");
  printf("        UPDATE staff\n");
  printf("          SET comm = 0.01 * (SELECT AVG(salary)\n");
  printf("                               FROM staff\n");
  printf("                               WHERE id >= 310)\n");
  printf("          WHERE CURRENT OF posCur2\n");
  printf("      }\n");
  printf("      FETCH posCur2 INTO :name, :dept\n");
  printf("    }\n");

  /* declare cursor */
  EXEC SQL DECLARE posCur2 CURSOR FOR
    SELECT name, dept FROM staff WHERE id >= 310 FOR UPDATE OF comm;

  /* open cursor */
  EXEC SQL OPEN posCur2;
  EMB_SQL_CHECK("cursor -- open");

  /* fetch cursor */
  EXEC SQL FETCH posCur2 INTO :name, :dept;
  EMB_SQL_CHECK("cursor -- fetch");

  while (sqlca.sqlcode != 100)
  {
    if (dept != 84)
    {
      EXEC SQL UPDATE staff
        SET comm = 0.01 * (SELECT AVG(salary)
                             FROM staff
                             WHERE id >= 310)
        WHERE CURRENT OF posCur2;
      EMB_SQL_CHECK("table -- positioned update using subquery");
    }

    EXEC SQL FETCH posCur2 INTO :name, :dept;
    EMB_SQL_CHECK("cursor -- fetch");
  }

  /* close cursor */
  EXEC SQL CLOSE posCur2;
  EMB_SQL_CHECK("cursor -- close");

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

  /* rollback the transaction */
  TransRollback();

  return 0;
} /* PositionedUpdateUsingSubqueryInSetClause */

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

  printf("\n-----------------------------------------------------------");
  printf("\nUSE THE SQL STATEMENTS:\n");
  printf("  DECLARE CURSOR\n");
  printf("  OPEN\n");
  printf("  FETCH\n");
  printf("  UPDATE\n");
  printf("  CLOSE\n");
  printf("TO PERFORM POSITIONED UPDATE ON A ROW\n");
  printf("USING CORRELATED SUBQUERY IN 'SET' CLAUSE.\n");

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

  printf("\n  Invoke the statements:\n");
  printf("    DECLARE posCur3 CURSOR FOR\n");
  printf("      SELECT name, dept FROM staff WHERE id >= 310");
  printf(" FOR UPDATE OF comm\n");
  printf("    OPEN posCur3\n");
  printf("    FETCH posCur3 INTO :name, :dept\n");
  printf("    while (successful fetch)\n");
  printf("    {\n");
  printf("      if (dept != 84)\n");
  printf("      {\n");
  printf("        UPDATE staff s1\n");
  printf("          SET comm = 0.01 * (SELECT AVG(salary)\n");
  printf("                               FROM staff s2\n");
  printf("                               WHERE id >= 310 AND\n");
  printf("                                     s2.dept = s1.dept)\n");
  printf("          WHERE CURRENT OF posCur3\n");
  printf("      }\n");
  printf("      FETCH posCur3 INTO :name, :dept\n");
  printf("    }\n");

  /* declare cursor */
  EXEC SQL DECLARE posCur3 CURSOR FOR
    SELECT name, dept FROM staff WHERE id >= 310 FOR UPDATE OF comm;

  /* open cursor */
  EXEC SQL OPEN posCur3;
  EMB_SQL_CHECK("cursor -- open");

  /* fetch cursor */
  EXEC SQL FETCH posCur3 INTO :name, :dept;
  EMB_SQL_CHECK("cursor -- fetch");

  while (sqlca.sqlcode != 100)
  {
    if (dept != 84)
    {
      EXEC SQL UPDATE staff s1
        SET comm = 0.01 * (SELECT AVG(salary)
                             FROM staff s2
                             WHERE id >= 310 AND
                                   s2.dept = s1.dept)
        WHERE CURRENT OF posCur3;
      EMB_SQL_CHECK("table -- pos. update using correl. subquery");
    }

    EXEC SQL FETCH posCur3 INTO :name, :dept;
    EMB_SQL_CHECK("cursor -- fetch");
  }

  /* close cursor */
  EXEC SQL CLOSE posCur3;
  EMB_SQL_CHECK("cursor -- close");

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

  /* rollback the transaction */
  TransRollback();

  return 0;
} /* UpdateUsingCorrelatedSubqueryInSetClause */

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

  printf("\n-----------------------------------------------------------");
  printf("\nUSE THE SQL STATEMENT:\n");
  printf("  DELETE\n");
  printf("TO DELETE TABLE DATA.\n");

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

  /* delete the table data without subqueries */
  printf("\n  Invoke the statement\n");
  printf("    DELETE FROM staff WHERE id >= 310 AND salary > 20000 AND job != 'Sales'\n");

  EXEC SQL DELETE FROM staff WHERE id >= 310 AND salary > 20000 AND job != 'Sales';
  EMB_SQL_CHECK("table -- delete without subqueries");

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

  /* rollback the transaction */
  TransRollback();

  return 0;
} /* DeleteWithoutSubqueries */

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

  printf("\n-----------------------------------------------------------");
  printf("\nUSE THE SQL STATEMENT:\n");
  printf("  DELETE\n");
  printf("TO DELETE TABLE DATA\n");
  printf("USING SUBQUERY IN 'WHERE' CLAUSE.\n");

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

  /* display selected content from employee table */
  printf("\n  SELECT empno, salary, workdept FROM employee");
  printf(" WHERE workdept = 'E11'\n");
  printf("    EMPNO  SALARY     WORKDEPT\n");
  printf("    ------ ---------- --------\n");

  EXEC SQL DECLARE c0 CURSOR FOR
    SELECT empno, salary, workdept FROM employee WHERE workdept = 'E11';

  EXEC SQL OPEN c0;
  EMB_SQL_CHECK("cursor -- open");

  EXEC SQL FETCH c0 INTO :empno, :salary, :workdept;
  EMB_SQL_CHECK("cursor -- fetch");

  while (sqlca.sqlcode != 100)
  {
    printf("    %-6s %10.2f %-8s\n", empno, salary, workdept);

    EXEC SQL FETCH c0 INTO :empno, :salary, :workdept;
    EMB_SQL_CHECK("cursor -- fetch");
  }

  EXEC SQL CLOSE c0;
  EMB_SQL_CHECK("cursor -- close");

  /* delete the table data using subquery in WHERE clause */
  printf("\n  Invoke the statement\n");
  printf("    DELETE FROM staff\n");
  printf("      WHERE id >= 310 AND\n");
  printf("            job != 'Sales' AND\n");
  printf("            salary > (SELECT AVG(salary)\n");
  printf("                        FROM employee\n");
  printf("                        WHERE workdept = 'E11')\n");

  EXEC SQL DELETE FROM staff
    WHERE id >= 310 AND
          job != 'Sales' AND
          salary > (SELECT AVG(salary)
                      FROM employee
                      WHERE workdept = 'E11');
  EMB_SQL_CHECK("table -- insert using values");

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

  /* rollback the transaction */
  TransRollback();

  return 0;
} /* DeleteUsingSubqueryInWhereClause */

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

  printf("\n-----------------------------------------------------------");
  printf("\nUSE THE SQL STATEMENT:\n");
  printf("  DELETE\n");
  printf("TO DELETE TABLE DATA\n");
  printf("USING A CORRELATED SUBQUERY IN 'WHERE' CLAUSE.\n");

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

  /* delete the table data using correlated subquery in WHERE clause */
  printf("\n  Invoke the statement\n");
  printf("    DELETE FROM staff s1\n");
  printf("      WHERE id >= 310 AND\n");
  printf("            job != 'Sales' AND\n");
  printf("            salary < (SELECT AVG(salary)\n");
  printf("                        FROM staff s2\n");
  printf("                        WHERE s2.dept = s1.dept)\n");

  EXEC SQL DELETE FROM staff s1
    WHERE id >= 310 AND
          job != 'Sales' AND
          salary < (SELECT AVG(salary)
                      FROM staff s2
                      WHERE s2.dept = s1.dept);
  EMB_SQL_CHECK("table -- delete using correl. subquery in WHERE clause");

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

  /* rollback the transaction */
  TransRollback();

  return 0;
} /* TbDeleteUsingCorrelatedSubqueryInWhereClause */

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

  printf("\n-----------------------------------------------------------");
  printf("\nUSE THE SQL STATEMENTS:\n");
  printf("  DECLARE CURSOR\n");
  printf("  OPEN\n");
  printf("  FETCH\n");
  printf("  DELETE\n");
  printf("  CLOSE\n");
  printf("TO PERFORM POSITIONED DELETE ON A ROW.\n");

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

  printf("\n  Invoke the statements:\n");
  printf("    DECLARE posCur4 CURSOR FOR\n");
  printf("      SELECT name, dept FROM staff WHERE id >= 310 AND job != 'Sales' \n");
  printf("    OPEN posCur4\n");
  printf("    FETCH posCur4 INTO :name, :dept\n");
  printf("    while (successful fetch)\n");
  printf("    {\n");
  printf("      if (dept != 84)\n");
  printf("      {\n");
  printf("        DELETE FROM staff WHERE CURRENT OF posCur4\n");
  printf("      }\n");
  printf("      FETCH posCur4 INTO :name, :dept\n");
  printf("    }\n");

  /* declare cursor */
  EXEC SQL DECLARE posCur4 CURSOR FOR
    SELECT name, dept FROM staff WHERE id >= 310 AND job != 'Sales' ;

  /* open cursor */
  EXEC SQL OPEN posCur4;
  EMB_SQL_CHECK("cursor -- open");

  /* fetch cursor */
  EXEC SQL FETCH posCur4 INTO :name, :dept;
  EMB_SQL_CHECK("cursor -- fetch");

  while (sqlca.sqlcode != 100)
  {
    if (dept != 84)
    {
      EXEC SQL DELETE FROM staff WHERE CURRENT OF posCur4;
      EMB_SQL_CHECK("table -- positioned delete");
    }

    EXEC SQL FETCH posCur4 INTO :name, :dept;
    EMB_SQL_CHECK("cursor -- fetch");
  }

  /* close cursor */
  EXEC SQL CLOSE posCur4;
  EMB_SQL_CHECK("cursor -- close");

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

  /* rollback the transaction */
  TransRollback();

  return 0;
} /* PositionedDelete */

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

  /* delete the table data without subqueries */
  printf("\n  Create table for the sample \n");

  EXEC SQL create table staff like staff;
  EMB_SQL_CHECK("create table staff");

  EXEC SQL insert into staff select * from staff;
  EMB_SQL_CHECK("insert data in table staff");

  return 0;
} /* CreateTableForSample */