Database

#include "stdafx.h"
   #include "windows.h"
   #include <sqlext.h>

   int main(int argc, char* argv[])
   {
   printf("Starting\r\n");

   SQLHANDLE hEnv; // ODBC Environment handle
   SQLHANDLE hDbc; // ODBC Connection handle
   SQLHANDLE hStmt; // ODBC Statement handle

   SQLRETURN status; // SQL return variable to test success or failure

   // 1. Create Environment Handle
   status = SQLAllocHandle(SQL_HANDLE_ENV, SQL_NULL_HANDLE, &hEnv);

   // 2. Set the ODBC Version we are using to 3.0
   status = SQLSetEnvAttr(hEnv, SQL_ATTR_ODBC_VERSION, (void *) SQL_OV_ODBC3, 0);

   // 3. Create a Connection Handle.
   status = SQLAllocHandle(SQL_HANDLE_DBC, hEnv, &hDbc);

   // 4. Set Connection Login Timeout to 5 seconds.
   status = SQLSetConnectAttr(hDbc, SQL_LOGIN_TIMEOUT,(void *) 5, 0);

   // 5. Open a Connection To Datasource (DSN
   status = SQLConnect(hDbc,(SQLWCHAR *) "postgres", SQL_NTS,
   (SQLWCHAR *) "postgres", SQL_NTS,
   (SQLWCHAR *) "dbpass", SQL_NTS); // connect to DSN

   // 6. Create SQL Statement Handle.
   status = SQLAllocHandle(SQL_HANDLE_STMT, hDbc, &hStmt);

   // 7. Set Cursor Type to Static.
   status = SQLSetStmtAttr(hStmt, SQL_ATTR_CURSOR_TYPE, (SQLPOINTER) SQL_CURSOR_STATIC, 0);

   // 8. Execute a SQL Statement. Here we get the employee records from Northwind database.
   status = SQLExecDirect(hStmt,(SQLWCHAR *) "Select * from lookup_hand_groups", SQL_NTS);

   // 9. Do whatever you will with the returned data. First, check to see that something
   // was returned.

   printf("After settings\r\n");
   // count the number of rows in the returned data
   int rowcnt; // variable to hold row count

   rowcnt = 0; // initialize row counter

   while (true) // loop forever
   {
   status = SQLFetch(hStmt); // fetch a row of data

   if (status == SQL_NO_DATA_FOUND) break; // if No Data was returned then exit the loop

   rowcnt++; // add 1 to the row counter
   }
   printf("rowcnt\r\n");

   printf("There were %d rows of data returned by the SQL Statement.\r\n", rowcnt);

   // Now, reset the cursor to the first row of data

   status = SQLFetchScroll(hStmt,SQL_FETCH_FIRST,0);

   if (rowcnt > 0) {
   SQLSMALLINT numcols; // variable to store number of SQL Columns

   status = SQLNumResultCols(hStmt, &numcols); // retrieve number of SQL Columns

   if (status == SQL_SUCCESS || status == SQL_SUCCESS_WITH_INFO) {
   printf("Number of returned Columns is: %d. \r\n",numcols);
   }
   else {
   printf("Error returning number of Columns...\r\n");
   }

   // Describe the Name of a Column in the returned data

   # define SQL_MAX_NAME_SIZE 128

   SQLSMALLINT iCol; // variable to hold column number to Describe

   iCol = 3; // Column Number to Describe

   SQLWCHAR namebuffer[SQL_MAX_NAME_SIZE + 1]; // buffer to receive column name

   SQLSMALLINT buffersize; // returns actual size of column name returned

   SQLSMALLINT typeOfData; // returns type of data in the column

   SQLUINTEGER columnsize; // returns size of the column

   SQLSMALLINT decimaldigits; // returns number of decimal digits for the column

   SQLSMALLINT nullable; // returns - does column allow NULLs? 1 = yes, 0 = No

   memset(namebuffer, 0, SQL_MAX_NAME_SIZE + 1); // initialize name buffer

   status = SQLDescribeCol(hStmt, iCol, namebuffer, SQL_MAX_NAME_SIZE, &buffersize, &typeOfData, &columnsize,
   &decimaldigits, &nullable); // Get Description of Column

   printf("Column name of column number %d is %s.\r\n",iCol, namebuffer);


   // Last, but not least, return the Column Data from the column number iCol shown above.

   int icol = iCol; // same column number as above
   long nchars; // number of characters returned

   char buffer[512]; // 512 character buffer

   memset(buffer,0,sizeof(buffer)); // initialize buffer

   // Get the Column Data and convert it to Character.
   status = SQLGetData(hStmt, icol, SQL_C_CHAR, buffer, sizeof(buffer) - 1, &nchars);

   printf("Data from Column %d is '%s'.\r\n",icol, buffer);
   }

   // 10. Close the Cursor if one was created...
   status = SQLCloseCursor(hStmt);

   if (status == SQL_SUCCESS || status == SQL_SUCCESS_WITH_INFO) {
   }
   else {
   printf("Error with SQLCloseCursor...\r\n");
   }

   // 11. Release the SQL Statement Handle.
   status = SQLFreeHandle(SQL_HANDLE_STMT, hStmt);

   // 12. Close the Connection
   status = SQLDisconnect(hDbc);

   // 13. Release the Connection Handle
   status = SQLFreeHandle(SQL_HANDLE_DBC, hDbc);

   // 14. Release the Environment Handle
   status = SQLFreeHandle(SQL_HANDLE_ENV, hEnv);

   printf("All Done!\n\nPress Any Key To Continue...");

   getchar(); // wait for a keypress -- not required in Visual Studio 6 but is in later ones

   return 0;
   }

cmd.CommandText = "SELECT * FROM GuestInfo WHERE Col2 = 12345"
Dim lrd As SqlDataReader = cmd.ExecuteReader()

cmd.CommandText = "SELECT * FROM GuestInfo WHERE Col1 = 'ABC'"
Dim lrd As SqlDataReader = cmd.ExecuteReader()

Dim str As String

str = "ABC"

cmd.CommandText = "SELECT * FROM GuestInfo WHERE Col1 = '" & str & "'"
Dim lrd As SqlDataReader = cmd.ExecuteReader()