How to connect with database?

[debiprasad_sahoo]

We are doing a project using C. We want to know how to connect with database.
Please post your replies soon. Its urgent. Please help.

 

[JGuru]

Connecting C language with a Database using ODBC

[b]
//This program connects to an ODBC data source called "db97".  It then executes a SQL statement “SELECT Model

// FROM Makes WHERE Make = 'Vauxhall';" which should return all models made by Vauxhall stored in the database
// Author: JGuru Name: sqlexecute.cpp

#include <windows.h>

#include <sqlext.h>

#include <stdio.h>

 

int main(void)

{

                HENV                      hEnv = NULL;                                                      // Env Handle from SQLAllocEnv()

                HDBC                      hDBC = NULL;                                                      // Connection handle

                HSTMT                   hStmt = NULL;                                                      // Statement handle

                UCHAR                   szDSN[SQL_MAX_DSN_LENGTH] = "db97";                // Data Source Name buffer
UCHAR*                  szUID = NULL;                                                      // User ID buffer

                UCHAR*                  szPasswd = NULL;                                                                // Password buffer

                UCHAR                   szModel[128];                                                        // Model buffer

                SDWORD             cbModel;                                                                 // Model buffer bytes recieved

                UCHAR                   szSqlStr[] = "Select Model From Makes Where Make='Vauxhall'";                // SQL string

                RETCODE              retcode;                                                                   // Return code

               

                // Allocate memory for ODBC Environment handle

                SQLAllocEnv (&hEnv);

 

                // Allocate memory for the connection handle

                SQLAllocConnect (hEnv, &hDBC);

               

                // Connect to the data source "db97" using userid and password.

                retcode = SQLConnect (hDBC, szDSN, SQL_NTS, szUID, SQL_NTS, szPasswd, SQL_NTS);

 

                if (retcode == SQL_SUCCESS || retcode == SQL_SUCCESS_WITH_INFO)

                {

                                // Allocate memory for the statement handle

                                retcode = SQLAllocStmt (hDBC, &hStmt);

               

                                // Prepare the SQL statement by assigning it to the statement handle

                                retcode = SQLPrepare (hStmt, szSqlStr, sizeof (szSqlStr));

 

                                // Execute the SQL statement handle

                                retcode = SQLExecute (hStmt);

                               

                                // Project only column 1 which is the models

                                SQLBindCol (hStmt, 1, SQL_C_CHAR, szModel, sizeof(szModel), &cbModel);

 

                                // Get row of data from the result set defined above in the statement

                                retcode = SQLFetch (hStmt);

 

                                while (retcode == SQL_SUCCESS || retcode == SQL_SUCCESS_WITH_INFO)

                                {

                                                printf ("\t%s\n", szModel);                                                // Print row (model)

                                                retcode = SQLFetch (hStmt);                                 // Fetch next row from result set

                                }

 

                                // Free the allocated statement handle

                                SQLFreeStmt (hStmt, SQL_DROP);

 

                                // Disconnect from datasource

                                SQLDisconnect (hDBC);

                }

               

                // Free the allocated connection handle

                SQLFreeConnect (hDBC);

 

                // Free the allocated ODBC environment handle

                SQLFreeEnv (hEnv);

                return 0;

}
[/b]

 

[debiprasad_sahoo]

Thanks JGuru. Please keep me supporting.