Conformance
Version Introduced:ODBC 1.0
Standards Compliance:ISO 92
Summary
SQLNumParams returns the number of parameters in an SQL statement.
Syntax
SQLRETURN SQLNumParams(
SQLHSTMTStatementHandle,
SQLSMALLINT *ParameterCountPtr);
Arguments
StatementHandle
[Input]
Statement handle.
ParameterCountPtr
[Output]
Pointer to a buffer in which to return the number of parameters in the statement.
Returns
SQL_SUCCESS, SQL_SUCCESS_WITH_INFO, SQL_STILL_EXECUTING, SQL_ERROR, or SQL_INVALID_HANDLE.
Diagnostics
When SQLNumParams returns SQL_ERROR or SQL_SUCCESS_WITH_INFO, an associated SQLSTATE value may be obtained by calling SQLGetDiagRec with a HandleType of SQL_HANDLE_STMT and a Handle of StatementHandle. The following table lists the SQLSTATE values commonly returned by SQLNumParams and explains each one in the context of this function; the notation “(DM)” precedes the descriptions of SQLSTATEs returned by the Driver Manager. The return code associated with each SQLSTATE value is SQL_ERROR, unless noted otherwise.
| SQLSTATE | Error | Description |
| 01000 | General warning | Driver-specific informational message. (Function returns SQL_SUCCESS_WITH_INFO.) |
| 08S01 | Communication link failure | The communication link between the driver and the data source to which the driver was connected failed before the function completed processing. |
| HY000 | General error | An error occurred for which there was no specific SQLSTATE and for which no implementation-specific SQLSTATE was defined. The error message returned by SQLGetDiagRec in the *MessageText buffer describes the error and its cause. |
| HY001 | Memory allocation error | The driver was unable to allocate memory required to support execution or completion of the function. |
| HY008 | Operation canceled | Asynchronous processing was enabled for the StatementHandle. The function was called and, before it completed execution, SQLCancel was called on the StatementHandle; the function was then called again on the StatementHandle. The function was called and, before it completed execution, SQLCancel was called on the StatementHandle from a different thread in a multithread application. |
| HY010 | Function sequence error | (DM) The function was called prior to calling SQLPrepare or SQLExecDirect for the StatementHandle. (DM) An asynchronously executing function (not this one) was called for the StatementHandle and was still executing when this function was called. (DM) SQLExecute, SQLExecDirect, SQLBulkOperations, or SQLSetPos was called for the StatementHandle and returned SQL_NEED_DATA. This function was called before data was sent for all data-at-execution parameters or columns. |
| HY013 | Memory management error | The function call could not be processed because the underlying memory objects could not be accessed, possibly because of low memory conditions. |
| HYT01 | Connection timeout expired | The connection timeout period expired before the data source responded to the request. The connection timeout period is set through SQLSetConnectAttr, SQL_ATTR_CONNECTION_TIMEOUT. |
| IM001 | Driver does not support this function | (DM) The driver associated with the StatementHandle does not support the function. |
Comments
SQLNumParams can be called only after SQLPrepare has been called.
If the statement associated with StatementHandle does not contain parameters, SQLNumParams sets *ParameterCountPtr to 0.
The number of parameters returned by SQLNumParams is the same value as the SQL_DESC_COUNT field of the IPD.
For more information, see “Describing Parameters” in Chapter 9, “Executing Statements.”
Related Functions
| For information about | See |
| Binding a buffer to a parameter | SQLBindParameter |
| Returning information about a parameter in a statement | SQLDescribeParam |