SQLMoreResults
SQLMoreResults birden çok sonuç satır kümesi almak uygulama sağlar. A Transact-SQLveya odbc gönderilen toplu bir compute yan tümcesi içeren bir select deyimi veya Transact-SQLdeyimleri, neden SQL Serverbirden çok sonuç kümeleri oluşturmak için yerel istemci odbc sürücüsü. SQL Serverher iki durumda da sonuçları işlemek için sunucu imleç oluşturma izin vermez. Bu nedenle, geliştirici, odbc deyimi engelliyor sağlamalıdır. Geliştirici, döndürülen verileri egzoz veya diğer etkin deyimleri bağlantı veri işleme önce odbc deyimi iptal gerekir.
[!NOT]
A Transact-SQLbir compute yan tümcesi içeren bir select deyimi yalnızca bir sunucu sürümü öncesinde bağlanırken desteklenir SQL Server 2012.
Geliştirici sonuç özelliklerini ayarlar compute yan tarafından oluşturulan satırları ve sütunları belirlemek için bir Transact-SQLselect deyimi. Daha ayrıntılı bilgi için bkz: SQLColAttribute.
Ne zaman SQLMoreResults denilen unfetched veri satırlarını sonuç kümesi ile bu satırlar kaybolur ve sonraki sonuç satır kümesi satır verileri kullanılabilir yapılır.
Örnekler
void GetComputedRows
(
SQLHSTMT hStmt
)
{
SQLUSMALLINT nCols;
SQLUSMALLINT nCol;
PODBCSETINFO pODBCSetInfo = NULL;
SQLRETURN sRet;
UINT nRow;
SQLINTEGER nComputes = 0;
SQLINTEGER nSet;
BYTE* pValue;
// If SQLNumResultCols failed, then some error occurred in
// statement execution. Exit.
if (!SQL_SUCCEEDED(SQLNumResultCols(hStmt, (SQLSMALLINT*) &nCols)))
{
goto EXIT;
}
// Determine the presence of COMPUTE clause result sets. The SQL
// Server Native Client ODBC driver uses column attributes to report multiple
// sets. The column number must be less than or equal to the
// number of columns returned. You are guaranteed to have at least
// one, so use '1' for the SQLColAttribute ColumnNumber
// parameter.
SQLColAttribute(hStmt, 1, SQL_CA_SS_NUM_COMPUTES,
NULL, 0, NULL, (SQLPOINTER) &nComputes);
// Create a result info structure pointer array, one element for
// the normal result rows and one for each compute result set.
// Initialize the array to NULL pointers.
pODBCSetInfo = new ODBCSETINFO[1 + nComputes];
// Process the result sets...
nSet = 0;
while (TRUE)
{
// If required, get the column information for the result set.
if (pODBCSetInfo[nSet].pODBCColInfo == NULL)
{
if (pODBCSetInfo[nSet].nCols == 0)
{
SQLNumResultCols(hStmt, (SQLSMALLINT*) &nCols);
pODBCSetInfo[nSet].nCols = nCols;
}
if (GetColumnsInfo(hStmt, pODBCSetInfo[nSet].nCols,
&(pODBCSetInfo[nSet].pODBCColInfo)) == SQL_ERROR)
{
goto EXIT;
}
}
// Get memory for bound return values if required.
if (pODBCSetInfo[nSet].pRowValues == NULL)
{
CreateBindBuffer(&(pODBCSetInfo[nSet]));
}
// Rebind columns each time the result set changes.
myBindCols(hStmt, pODBCSetInfo[nSet].nCols,
pODBCSetInfo[nSet].pODBCColInfo,
pODBCSetInfo[nSet].pRowValues);
// Set for ODBC row array retrieval. Fast retrieve for all
// sets. COMPUTE row sets have only a single row, but
// normal rows can be retrieved in blocks for speed.
SQLSetStmtAttr(hStmt, SQL_ATTR_ROW_BIND_TYPE,
(void*) pODBCSetInfo[nSet].nResultWidth, SQL_IS_UINTEGER);
SQLSetStmtAttr(hStmt, SQL_ATTR_ROW_ARRAY_SIZE,
(void*) pODBCSetInfo[nSet].nRows, SQL_IS_UINTEGER);
SQLSetStmtAttr(hStmt, SQL_ATTR_ROWS_FETCHED_PTR,
(void*) &nRowsFetched, sizeof(SQLINTEGER));
while (TRUE)
{
// In ODBC 3.x, SQLFetch supports arrays of bound rows or
// columns. SQLFetchScroll (or ODBC 2.x SQLExtendedFetch)
// is not necessary to support fastest retrieval of
// data rows.
if (!SQL_SUCCEEDED(sRet = SQLFetch(hStmt)))
{
break;
}
for (nRow = 0; nRow < (UINT) nRowsFetched; nRow++)
{
for (nCol = 0; nCol < pODBCSetInfo[nSet].nCols;
nCol++)
{
// Processing row and column values...
}
}
}
// sRet is not SQL_SUCCESS and is not SQL_SUCCESS_WITH_INFO.
// If it's SQL_NO_DATA, then continue. If it's an
// error state, stop.
if (sRet != SQL_NO_DATA)
{
break;
}
// If there's another set waiting, determine the result set
// indicator. The indicator is 0 for regular row sets or an
// ordinal indicating the COMPUTE clause responsible for the
// set.
if (SQLMoreResults(hStmt) == SQL_SUCCESS)
{
sRet = SQLColAttribute(hStmt, 1, SQL_CA_SS_COMPUTE_ID,
NULL, 0, NULL, (SQLPOINTER) &nSet);
}
else
{
break;
}
}
EXIT:
// Clean-up anything dynamically allocated and return.
return;
}
void GetComputedRows
(
SQLHSTMT hStmt
)
{
SQLUSMALLINT nCols;
SQLUSMALLINT nCol;
PODBCSETINFO pODBCSetInfo = NULL;
SQLRETURN sRet;
UINT nRow;
SQLINTEGER nComputes = 0;
SQLINTEGER nSet;
BYTE* pValue;
// If SQLNumResultCols failed, then some error occurred in
// statement execution. Exit.
if (!SQL_SUCCEEDED(SQLNumResultCols(hStmt, (SQLSMALLINT*) &nCols)))
{
goto EXIT;
}
// Determine the presence of COMPUTE clause result sets. The SQL
// Server Native Client ODBC driver uses column attributes to report multiple
// sets. The column number must be less than or equal to the
// number of columns returned. You are guaranteed to have at least
// one, so use '1' for the SQLColAttribute ColumnNumber
// parameter.
SQLColAttribute(hStmt, 1, SQL_CA_SS_NUM_COMPUTES,
NULL, 0, NULL, (SQLPOINTER) &nComputes);
// Create a result info structure pointer array, one element for
// the normal result rows and one for each compute result set.
// Initialize the array to NULL pointers.
pODBCSetInfo = new ODBCSETINFO[1 + nComputes];
// Process the result sets...
nSet = 0;
while (TRUE)
{
// If required, get the column information for the result set.
if (pODBCSetInfo[nSet].pODBCColInfo == NULL)
{
if (pODBCSetInfo[nSet].nCols == 0)
{
SQLNumResultCols(hStmt, (SQLSMALLINT*) &nCols);
pODBCSetInfo[nSet].nCols = nCols;
}
if (GetColumnsInfo(hStmt, pODBCSetInfo[nSet].nCols,
&(pODBCSetInfo[nSet].pODBCColInfo)) == SQL_ERROR)
{
goto EXIT;
}
}
// Get memory for bound return values if required.
if (pODBCSetInfo[nSet].pRowValues == NULL)
{
CreateBindBuffer(&(pODBCSetInfo[nSet]));
}
// Rebind columns each time the result set changes.
myBindCols(hStmt, pODBCSetInfo[nSet].nCols,
pODBCSetInfo[nSet].pODBCColInfo,
pODBCSetInfo[nSet].pRowValues);
// Set for ODBC row array retrieval. Fast retrieve for all
// sets. COMPUTE row sets have only a single row, but
// normal rows can be retrieved in blocks for speed.
SQLSetStmtAttr(hStmt, SQL_ATTR_ROW_BIND_TYPE,
(void*) pODBCSetInfo[nSet].nResultWidth, SQL_IS_UINTEGER);
SQLSetStmtAttr(hStmt, SQL_ATTR_ROW_ARRAY_SIZE,
(void*) pODBCSetInfo[nSet].nRows, SQL_IS_UINTEGER);
SQLSetStmtAttr(hStmt, SQL_ATTR_ROWS_FETCHED_PTR,
(void*) &nRowsFetched, sizeof(SQLINTEGER));
while (TRUE)
{
// In ODBC 3.x, SQLFetch supports arrays of bound rows or
// columns. SQLFetchScroll (or ODBC 2.x SQLExtendedFetch)
// is not necessary to support fastest retrieval of
// data rows.
if (!SQL_SUCCEEDED(sRet = SQLFetch(hStmt)))
{
break;
}
for (nRow = 0; nRow < (UINT) nRowsFetched; nRow++)
{
for (nCol = 0; nCol < pODBCSetInfo[nSet].nCols;
nCol++)
{
// Processing row and column values...
}
}
}
// sRet is not SQL_SUCCESS and is not SQL_SUCCESS_WITH_INFO.
// If it's SQL_NO_DATA, then continue. If it's an
// error state, stop.
if (sRet != SQL_NO_DATA)
{
break;
}
// If there's another set waiting, determine the result set
// indicator. The indicator is 0 for regular row sets or an
// ordinal indicating the COMPUTE clause responsible for the
// set.
if (SQLMoreResults(hStmt) == SQL_SUCCESS)
{
sRet = SQLColAttribute(hStmt, 1, SQL_CA_SS_COMPUTE_ID,
NULL, 0, NULL, (SQLPOINTER) &nSet);
}
else
{
break;
}
}
EXIT:
// Clean-up anything dynamically allocated and return.
return;
}