111、ProC动态SQL示例(第1,2,3种方法)

下面是ProC前三种动态SQL的完整示例。

(1)动态SQL1: 不能是查询(SELECT)语句,并且没有宿主变量.
用法:拼一句动态SQL语句,并用EXECUTE IMMEDIATE执行,如:

EXEC SQL EXECUTE IMMEDIATE CREATE TABLE test (test_col VARCHAR2(4));
EXEC SQL EXECUTE IMMEDIATE INSERT INTO TABLE test ('AAAA');
EXEC SQL EXECUTE IMMEDIATE DELETE test WHERE test_col='AAAA';

(2)动态SQL2: 不能是查询(SELECT)语句,并且输入的宿主变量数目是知道的,
用法:拼一句动态SQL语句,用PREPARE,EXECUTE语句执行.
strcpy(sqlstring, "DELETE FROM test WHERE test_col = :?");
EXEC SQL PREPARE sqlproc FROM :sqlstring;
EXEC SQL EXECUTE sqlproc USING :emp_number;

下文示例中大多数是采用动态SQL2.

(3)动态SQL3: 用于创建动态查询, 并且要查询的字段以及输入的宿主变量数目是知道的
用法: 拼一句动态SQL语句,用PREPARE分析该语句,并要定义一个CURSOR进行取值
如:要查询的数据在多张表中，select user_name from，可采用动态SQL3来进行查询
strcpy(sql,"select user_name from ");
strcat(sql,"table1");//table2,table3,table4
EXEC SQL PREPARE sqlproc FROM :sql;
EXEC SQL DECLARE cur_user_name CURSOR FOR sqlproc;
EXEC SQL OPEN cur_user_name;
while(1)
{
EXEC SQL FETCH cur_user_name into :ora_id;
if (sqlca.sqlcode < 0)
{
/*FETCH CURSOR失败*/
printf("fetch cursor fail,sqlcode=%ld,sqlserr=%s",sqlca.sqlcode,sqlca.sqlerrm.sqlerrmc);
}
if( sqlca.sqlcode == SQLNOTFOUND)
{
break;
}
}
EXEC SQL CLOSE cur_user_name;

下文示例中Case5也是采用这种方法.

//Proc 示例

#include <stdio.h>
#include <string.h>
#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include "sqlca.h"
#include <ctype.h>

//变量，过程预声明
int i;
char screen[1];
char cmd[1];

//**********************************************************
//CASE对应与db_selectop的switch
EXEC SQL BEGIN DECLARE SECTION;

VARCHAR oraName[30];    //CASE 1,2,3

VARCHAR oraValue[20];    //CASE 1,2,3,5
int oraCount;          //CASE 1,2,3,4,5
VARCHAR oraSql[30],oraTable[20]; //CASE 4,5

VARCHAR oraField[10];    //CASE 5
VARCHAR oraCountSql[30];   //CASE 5

VARCHAR oraCode[10];    //CASE 6
VARCHAR oraContent[10];    //CASE 6

EXEC SQL END DECLARE SECTION;
//**********************************************************

int db_connect();
int db_selectop();

//void dy_tablecount();
//void dy_tablefield();
void view_tabledata();

void pause();
void sql_error(char *);

//主函数
void main()
{
EXEC SQL INCLUDE sqlca;
EXEC ORACLE OPTION (RELEASE_CURSOR = YES);
EXEC SQL WHENEVER SQLERROR DO sql_error(" <ERROR> ");

if(db_connect()==0)
{
db_selectop();
}
}

//打开数据连接
int db_connect()
{

EXEC SQL BEGIN DECLARE SECTION;
VARCHAR oraCN[30];
EXEC SQL END DECLARE SECTION;

printf("----------------------------------");
printf("\n [ Examples With Oracle DB ]\n");
printf("----------------------------------");
printf("\n                   Designed by Liwei 2005\n");
cmd[0]='A';
while(cmd[0]!='0' && cmd[0]!='1')
{

printf("\n Confirm DB Source:");
printf("\n 1:workflow/workflow@if");
printf("\n 0:Exit;");
printf("\n Choose:");

gets(cmd);
switch(cmd[0])
{
   case '1':
    strcpy(oraCN.arr,"workflow/workflow@if");
    oraCN.len = strlen(oraCN.arr);
    oraCN.arr[oraCN.len]='\0';

    //EXEC SQL WHENEVER SQLERROR GOTO cnError;
    EXEC SQL CONNECT :oraCN;
   
    printf("\n [OK Connected!] ");
    return 0;

  
    break;
   case '0':
    break;
   default:
    printf("\n [Error Input!] \n");
    break;
}

}

exit(0);

//cnError:
// printf("\n [Error Oracle Connected!]");
// return 1;
}

//选择数据操作
int db_selectop()
{
char order[1];

cmd[0]='A';
//order[0]='A';

while(cmd[0]!='0')
{
printf("\n ");
printf("\n Select DB Method:");
printf("\n -------------------------------------------");
printf("\n 1: GetTableCount      STATIC [CLASS_FLOW]");
printf("\n 2: GetTableField One STATIC [CLASS_FLOW]");
printf("\n 3: GetTableField Muti STATIC [USE_POWER]");
printf("\n");
printf("\n 4: GetTableCount      DYNAMIC      ");
printf("\n 5: GetTableField One DYNAMIC      ");
printf("\n");
printf("\n 6: EditTable USE_DEPT");
printf("\n -------------------------------------------");
printf("\n 0: Exit");
printf("\n\n Enter:");

gets(cmd);

switch(cmd[0])
{
   case '1':
   
    EXEC SQL SELECT NVL(COUNT(*),0) INTO :oraCount FROM CLASS_FLOW;
   
    printf("\n <The Table Count> ");
    printf("%d",oraCount);
    pause();
    break;

   case '2':
   
    EXEC SQL DECLARE curOne CURSOR FOR SELECT DISTINCT FLOW_NAME FROM CLASS_FLOW WHERE FLOW_CLASS='请假';
    EXEC SQL SELECT COUNT(DISTINCT FLOW_NAME) INTO :oraCount FROM CLASS_FLOW WHERE FLOW_CLASS='请假';
    EXEC SQL OPEN curOne;
   
    for(i=1;i<=oraCount;i++)
    {   
     EXEC SQL FETCH curOne INTO :oraName;
     oraName.arr[oraName.len]='\0';
     printf("\n <Field List> ");
     printf("%s",oraName.arr);
    }
    EXEC SQL CLOSE curOne;
    pause();
    break;

   case '3':

    EXEC SQL DECLARE curMuti CURSOR FOR SELECT POWER_ID,POWER_NAME FROM USE_POWER ORDER BY POWER_ID ASC;
    EXEC SQL SELECT COUNT(*) INTO :oraCount FROM USE_POWER;
    EXEC SQL OPEN curMuti;
   
    for(i=1;i<=oraCount;i++)
    {   
     EXEC SQL FETCH curMuti INTO :oraValue,:oraName;
     oraValue.arr[oraValue.len]='\0';
     oraName.arr[oraName.len]='\0';
     printf("\n <Fields List> ");
     printf("%-8s",oraValue.arr);
     printf("%-20s",oraName.arr);
    }

    EXEC SQL CLOSE curMuti;

    pause();
    break;

   case '4':

    //EXEC SQL BEGIN DECLARE SECTION;
    //VARCHAR oraSql[30],oraTable[20];
    //int oraCount;
    //EXEC SQL END DECLARE SECTION;

    printf("\n Custom Table ");
    printf("\n ----------------------- ");
    printf("\n Input Table Name:");
    gets(oraTable.arr);

    oraTable.len=strlen(oraTable.arr);
    oraTable.arr[oraTable.len]='\0';

    strcpy(oraSql.arr,"SELECT COUNT(*) FROM ");
    strcat(oraSql.arr,oraTable.arr);
    oraSql.len=strlen(oraSql.arr);
    oraSql.arr[oraSql.len]='\0';

    printf("\n <SQL STATE> ");
    printf(oraSql.arr);
    printf("\n ");

    EXEC SQL PREPARE sqlDyCount FROM :oraSql;
    EXEC SQL DECLARE curDyCount CURSOR FOR sqlDyCount;
    EXEC SQL OPEN curDyCount;
    EXEC SQL FETCH curDyCount INTO :oraCount;
    EXEC SQL CLOSE curDyCount;

    printf("\n <Table Count> ");
    printf("%d",oraCount);
    //dy_tablecount();
    pause();
    break;

   case '5':

    //EXEC SQL BEGIN DECLARE SECTION;
    //VARCHAR oraSql[30],oraTable[10],oraField[10],oraValue[20];
    //VARCHAR oraCountSql[30];
    //int oraCount;
    //EXEC SQL END DECLARE SECTION;

    //接受屏幕数据
    printf("\n Custom Table And Field ");
    printf("\n ----------------------- ");
    printf("\n Input Table Name:");
    gets(oraTable.arr);
    oraTable.len=strlen(oraTable.arr);
    oraTable.arr[oraTable.len]='\0';
    printf(" Input Field Name:");
    gets(oraField.arr);
    oraField.len=strlen(oraField.arr);
    oraField.arr[oraField.len]='\0';

    //组合SELECT语句
    strcpy(oraSql.arr,"SELECT ");
    strcat(oraSql.arr,oraField.arr);
    strcat(oraSql.arr," FROM ");
    strcat(oraSql.arr,oraTable.arr);
    oraSql.len=strlen(oraSql.arr);
    oraSql.arr[oraSql.len]='\0';
    printf("\n <SQL STATE> ");
    printf(oraSql.arr);
    printf("\n");
    //读取内容
    EXEC SQL PREPARE sqlDy FROM :oraSql;
    EXEC SQL DECLARE curDyField CURSOR FOR sqlDy;
    EXEC SQL OPEN curDyField;

    //组合SELECT COUNT语句
    strcpy(oraCountSql.arr,"SELECT COUNT(*) FROM ");
    strcat(oraCountSql.arr,oraTable.arr);
    oraCountSql.len=strlen(oraCountSql.arr);
    oraCountSql.arr[oraCountSql.len]='\0';
    //读取数
    EXEC SQL PREPARE sqlDyCount FROM :oraCountSql;
    EXEC SQL DECLARE curDyFieldCount CURSOR FOR sqlDyCount;
    EXEC SQL OPEN curDyFieldCount;
    EXEC SQL FETCH curDyFieldCount INTO :oraCount;

    for(i=1;i<=oraCount;i++)
    {
    EXEC SQL FETCH curDyField INTO :oraValue;
    oraValue.arr[oraValue.len]='\0';
    printf("\n <Field List> ");
    printf("%s",oraValue.arr);
    }
    EXEC SQL CLOSE curDyFieldCount;
    EXEC SQL CLOSE curDyField;
    //dy_tablefield();
    pause();
    break;

   case '6':

    order[0]='A';
    while(order[0]!='0')
    {
     printf("\n ");
     printf("\n Edit Table ");
     printf("\n -------------");
     printf("\n 1: VIEW");
     printf("\n 2: INSERT");
     printf("\n 3: DELETE");
     printf("\n 4: UPDATE");
     printf("\n -------------");
     printf("\n 0: EXIT");
     printf("\n\n Enter:");
     gets(order);

     switch(order[0])
     {
     case '1':
      view_tabledata();
      pause();
      break;
     case '2':
      //INSERT
      printf("\n INSERT ");
      printf("\n ----------------------- ");
      printf("\n ENTER CODE:");
      gets(oraCode.arr);
      oraCode.len=strlen(oraCode.arr);
      oraCode.arr[oraCode.len]='\0';
      printf(" ENTER CONTENT:");
      gets(oraContent.arr);
      oraContent.len=strlen(oraContent.arr);
      oraContent.arr[oraContent.len]='\0';

      EXEC SQL INSERT INTO USE_DEPT VALUES(:oraCode,:oraContent);
      EXEC SQL COMMIT;
      pause();
      break;
     case '3':
      view_tabledata();
      //DELETE
      printf("\n DELETE ");
      printf("\n ----------------------- ");
      printf("\n ENTER CODE:");
      gets(oraCode.arr);
      oraCode.len=strlen(oraCode.arr);
      oraCode.arr[oraCode.len]='\0';
      EXEC SQL DELETE USE_DEPT WHERE DEPT_ID=:oraCode;
      EXEC SQL COMMIT;
      //strcpy(c_sql, "DELETE FROM EMP WHERE EMPNO = :?");
      //EXEC SQL PREPARE sql_stmt FROM :c_sql;
      //EXEC SQL EXECUTE sql_stmt USING :emp_number;
      pause();
      break;
     case '4':
      view_tabledata();
      //UPDATE
      printf("\n UPDATE ");
      printf("\n ----------------------- ");
      printf("\n ENTER CODE:");
      gets(oraCode.arr);
      oraCode.len=strlen(oraCode.arr);
      oraCode.arr[oraCode.len]='\0';
      printf(" ENTER CONTENT:");
      gets(oraContent.arr);
      oraContent.len=strlen(oraContent.arr);
      oraContent.arr[oraContent.len]='\0';

      EXEC SQL UPDATE USE_DEPT SET DEPT_NAME=:oraContent WHERE DEPT_ID=:oraCode;
      EXEC SQL COMMIT;

      pause();
      break;
     default:
      break;
     }
    }
    cmd[0]='6';
    break;

   default:
    break;
}

}
return 0;

}

void view_tabledata()
{
//VIEW
EXEC SQL DECLARE curTable CURSOR FOR SELECT DEPT_ID,DEPT_NAME FROM USE_DEPT ORDER BY DEPT_ID ASC;
EXEC SQL SELECT COUNT(*) INTO :oraCount FROM USE_DEPT;
EXEC SQL OPEN curTable;

printf("\n ");
printf("%-8s","CODE");
printf("%-20s","CONTENT");
printf("\n--------------------");

for(i=1;i<=oraCount;i++)
{   
EXEC SQL FETCH curTable INTO :oraValue,:oraName;
oraValue.arr[oraValue.len]='\0';
oraName.arr[oraName.len]='\0';
printf("\n ");
printf("%-8s",oraValue.arr);
printf("%-20s",oraName.arr);
}

printf("\n--------------------");

EXEC SQL CLOSE curTable;
}
//暂停屏幕
void pause()
{
printf("\n\n--Press Enter To Continue--");
gets(screen);

}
//显示意外错误
void sql_error(char *msg)
{
//printf("\n%s %ld %s\n", msg,sqlca.sqlcode,(char *)sqlca.sqlerrm.sqlerrmc);
printf("\n%s %s\n", msg,(char *)sqlca.sqlerrm.sqlerrmc);
//EXEC SQL ROLLBACK RELEASE;
db_selectop();
}

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