ESQL 资料（完全版）(6)

2019-04-08 19:07

#include /* Defines for BINDING */ /*初试化SQLDA*/

int init_da (SQLDA **DAPointer, int DAsqln); /*为存放列数据的sd_column结构申请空间*/ int alloc_host_vars (SQLDA *sqldaPointer); /*释放SQLDA所申请的空间*/ void free_da (SQLDA *sqldaPointer); /*获取列名信息*/

char * readColName (SQLDA *sqldaPointer, short sd_columnIndex, char * buffer); /*获取列数据*/

char * readCol (SQLDA *sqldaPointer, short sd_columnIndex, char * buffer); #ifdef __cplusplus } #endif

/*定义最大列数*/

#define MAX_COLUMNS255

#define MAX_CHAR_FOR_DOUBLE20 #define MAX_CHAR_FOR_LONG15 #define MAX_CHAR_FOR_DATETIME30 #define MAX_CHAR_FOR_DEFAULT100 EXEC SQL INCLUDE SQLCA ; EXEC SQL INCLUDE SQLDA ; #define SQLSTATE sqlca.sqlstate #define SQLCODE sqlca.sqlcode /*处理SQL语句*/

int process_statement( char * ) ; int main() { int rc ; char st[1024]; char tmpstr[1024]; /*获得SQL语句*/

printf(Please enter the any sql statement:); gets( st); /* 处理该语句 */

rc = process_statement( st ) ; /*打印处理结果*/ printf( %d, rc);

printf(the sqlcode is %d,SQLCODE); }

/****************************************************************************** * FUNCTION : process_statement * 处理SQL语句

*****************************************************************************/ int process_statement ( char * sqlInput ) { int counter = 0 ; SQLDA * sqldaPointer ;

short sqlda_d ; /* Total columns */ short idx; char buffer[4096]; char varname[1024]; char colnamelist[4096];

EXEC SQL BEGIN DECLARE SECTION ; char st[1024] ;

EXEC SQL END DECLARE SECTION ; strcpy( st, sqlInput ) ; /* 为SQLDA结构申请空间 */

if (init_da( &sqldaPointer, MAX_COLUMNS ) == -1) { return -1; }

/*准备SQL语句*/

EXEC SQL PREPARE statement1 from :st ; if (SQLCODE < 0) {

free_da(sqldaPointer); return SQLCODE; }

/*获取查询列的信息到SQLDA结构*/

EXEC SQL DESCRIBE statement1 USING DESCRIPTOR sqldaPointer ; /* 如果SQLCODE为0，则表示为SELECT语句 */ if ( SQLCODE != 0 ) { free_da(sqldaPointer); return SQLCODE; } /* end if */

sqlda_d = sqldaPointer->sd_sqld ; if ( sqlda_d > 0 ) {

/* 为存放列数据的sd_column结构申请空间 */ if (alloc_host_vars( sqldaPointer ) == -1) {free_da(sqldaPointer); return -1; }

/*声明游标*/

EXEC SQL DECLARE pcurs CURSOR FOR statement1 ; /打开游标*/

EXEC SQL OPEN pcurs ; if (SQLCODE < 0)

return SQLCODE;

/*取一行数据到SQLDA结构*/

EXEC SQL FETCH pcurs INTO DESCRIPTOR sqldaPointer; if (SQLCODE < 0) {

EXEC SQL CLOSE pcurs ; return SQLCODE; }

/*显示列标题 */ colnamelist[0] = 0;

for ( idx=0; idx< sqlda_d; idx++)

{ strcat(colnamelist, readColName(sqldaPointer, idx, buffer)); if (idx < sqlda_d -1) strcat(colnamelist, ,); }

/* 显示行数据*/

while ( SQLCODE == 0 ) { counter++ ;

for ( idx=0; idx< sqlda_d; idx++)

printf(%s,readCol(sqldaPointer, idx, buffer));

EXEC SQL FETCH pcurs INTO DESCRIPTOR sqldaPointer ; } /* endwhile */ /*关闭游标*/

EXEC SQL CLOSE pcurs ;

EXEC SQL DEALLOCATE CURSOR pcurs; /* 释放为SQLDA申请的空间 */ free_da( sqldaPointer ) ; } else { /* 不是SELECT语句*/ EXEC SQL EXECUTE statement1 ; free_da( sqldaPointer ) ; if (SQLCODE < 0) return SQLCODE; } /* end if */ return( 0 ) ;

} /* end of program : ADHOC.CP */

/******************************************************************************* PROCEDURE : init_da *为SQLDA分配空间。使用SQLDASIZE 获得SQLDA的大小。如果返回-1，则表示分配 *空间不成功。

******************************************************************************/ int init_da (SQLDA **DAPointer, int DAsqln) { int idx;

*DAPointer = (SQLDA *)malloc(SYB_SQLDA_SIZE(DAsqln)); if (*DAPointer == NULL) return (-1);

memset (*DAPointer, \\0, SYB_SQLDA_SIZE(DAsqln)); (*DAPointer)->sd_sqln = DAsqln; (*DAPointer)->sd_sqld = 0; return 0; }

/******************************************************************************* FUNCTION : alloc_host_vars *为存放列数据的sd_column结构申请空间。如果返回-1，则表示不能获得足够内存。 ******************************************************************************/ int alloc_host_vars (SQLDA *sqldaPointer) { short idx;

for (idx = 0; idx < sqldaPointer->sd_sqld; idx++) {

switch (sqldaPointer->sd_column[idx].sd_datafmt.datatype ) { case CS_CHAR_TYPE: case CS_VARCHAR_TYPE: