PT-20 Programming Guide
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Other value: the quantity of the data.
WriteField
Purpose
：
Use this function can revise the designated record in the existed file.
Syntax
：
int WriteField(_DBMS* F_Search, int recordno, int fieldno, char* field);
Example call
：
c
har str_field[10]=”123456789”;
WriteField(&fsearch,0,1, str_field);// Revise the second field of the first
data to “str_field”.
As revising success, file index will be moved to the front of the record
included revising field.
Includes
：
#include “DBMS.h”
Description
：
Using WriteField function can copy the field of appointed record. If the file
in disc D that you want to write, it will not allow to write.
Returns
：
-1: Write into defeat.
Other value: Write into the amount of data.
WriteRecord
Purpose
：
Using this function can copy the existed record.
Syntax
：
int WriteRecord(_DBMS* F_Search, int recordno, char* record);
Example call
：
char str_record[20]=”A123456,PA-20,2330”;
WriteRecord(&fsearch,0, str_record);// Revise the first record to char
str_record
。
Includes
：
#include “DBMS.h”
Description
：
Use WriteRecord function can copy the existed record, but unable to
increase a new record.
As revising success, file index will be moved to revise the front of revising
record. If the file in disc D that you want to write, it will not allow to write.
Returns
：
-1: Write into defeat.
Other value: Write into the amount of data.
ReadField
Purpose
：
Use this function to read the data of appointed field in the appointed
record.
Syntax
：
int ReadField(_DBMS* F_Search, int recordno, int fieldno, char* buffer);
Example call
：
char str_buffer[30];
ReadField(&fsearch,5,0,str_buffer);//Reading the data of first field in the
sixth record, and store to “str_buffer”.
Includes
：
#include “DBMS.h”
Description
：
int recordno : Read of record position.
int fieldno : Read of field position.
char* buffer : Read the storing space of field
。
