Querying Data
After Connecting, you can allocate a statement handle and execute the statement.
SELECT Procedure
Use SQLExecDirect to execute the statement and SQLFetch to fetch the records. You can use SQLBindCol to bind variables to columns in the result set. The numbering of the result set columns starts at 1.
SQLAllocHandle(SQL_HANDLE_ENV, SQL_NULL_HANDLE, &henv); SQLSetEnvAttr(henv, SQL_ATTR_ODBC_VERSION, (void*)SQL_OV_ODBC3, 0); SQLAllocHandle(SQL_HANDLE_DBC, henv, &hdbc); SQLDriverConnect(hdbc, 0, (SQLCHAR*)"Dsn=CData MicrosoftProject Source", SQL_NTS, 0, 0, 0, 0); SQLAllocHandle(SQL_HANDLE_STMT, hdbc, &hstmt); SQLExecDirect(hstmt, (SQLCHAR*)"SELECT Name FROM Projects WHERE Name =; 'Tax Checker'", SQL_NTS); SQLCHAR sName[20] = {0}; SQLLEN cbName = 0; SQLBindCol(hstmt, 1, SQL_C_CHAR, sName, 20, &cbName); SQLRETURN retcode = SQLFetch(hstmt); if (retcode == SQL_SUCCESS || retcode == SQL_SUCCESS_WITH_INFO) { ... }
Iterating over the Results
You can use SQLGetData to get values while iterating through a cursor. To iterate over the results, use SQLFetch to fetch rows and SQLGetData to retrieve the column values.
SQLHENV henv; SQLHDBC hdbc; SQLHSTMT hstmt; char sId[255] = {0}; SQLLEN cbId = 0; if (SQLAllocHandle(SQL_HANDLE_ENV, 0 ,&henv) == SQL_SUCCESS) { SQLSetEnvAttr(henv, SQL_ATTR_ODBC_VERSION, (void*)SQL_OV_ODBC3, 0); if (SQLAllocHandle(SQL_HANDLE_DBC, henv ,&hdbc) == SQL_SUCCESS) { if (SQLConnect(hdbc, "CData MicrosoftProject Source", SQL_NTS, 0, 0, 0, 0) == SQL_SUCCESS) { if (SQLAllocHandle(SQL_HANDLE_STMT, hdbc ,&hstmt) == SQL_SUCCESS) { if (SQLExecDirect(hstmt, "SELECT Id FROM Projects WHERE Name =; 'Tax Checker'", SQL_NTS) == SQL_SUCCESS) { while(SQLFetch(hstmt) == SQL_SUCCESS) { if (SQLGetData(hstmt, 1, SQL_C_CHAR, (SQLPOINTER)sId, 255, &cbId) == SQL_SUCCESS) { printf("Id: %s\n", sId); } } } SQLFreeHandle(SQL_HANDLE_STMT, hstmt); } SQLDisconnect(hdbc); } SQLFreeHandle(SQL_HANDLE_DBC, hdbc); } SQLFreeHandle(SQL_HANDLE_ENV, henv); }