SQLNumParams

SQLNumParams

SQLNumParams returns the number of parameters in a SQL statement.

Syntax

SQLRETURN  SQLNumParams (
    SQLHSTMT            stmt,
    SQLSMALLINT *       parameterCounterPtr );

Arguments

Data Type	Argument	In/Out	Description
SQLHSTMT	stmt	Input	Statement handle
SQLSMALLINT *	parameterCountPtr	Output	Pointer of the number of the parameters

Return Values

SQL_SUCCESS

Description

This function can be called only after SQLPrepare() is called.

If the stmt does not include parameters, SQLNumParams() will set 0 in *parameterCountPtr.

Diagnosis

SQLSTATE	Description	Comments
HY000	General error

Related Functions

SQLBindParameter
SQLDescribeParam    

Example

< Refer to: $ALTIBASE_HOME/sample/SQLCLI/demo_info2.cpp >

SQLPrepare(hstmt, Statement, SQL_NTS);

// Check to see if there are any parameters. If so, process them.
SQLNumParams(hstmt, &NumParams);
if (NumParams) {
   // Allocate memory for three arrays. The first holds pointers to buffers in which
   // each parameter value will be stored in character form. The second contains the
   // length of each buffer. The third contains the length/indicator value for each
   // parameter.
   PtrArray = (SQLPOINTER *) malloc(NumParams * sizeof(SQLPOINTER));
   BufferLenArray = (SQLINTEGER *) malloc(NumParams * sizeof(SQLINTEGER));
   LenOrIndArray = (SQLINTEGER *) malloc(NumParams * sizeof(SQLINTEGER));

   for (i = 0; i < NumParams; i++) {
   // Describe the parameter.
   SQLDescribeParam(hstmt, i + 1, &DataType, &ParamSize, &DecimalDigits, &Nullable);

   // Call a helper function to allocate a buffer in which to store the parameter
   // value in character form. The function determines the size of the buffer from
   // the SQL data type and parameter size returned by SQLDescribeParam and returns
   // a pointer to the buffer and the length of the buffer.
   PtrArray[i] = (char*)malloc(ParamSize);
   BufferLenArray[i] = SQL_NTS;


   // Bind the memory to the parameter. Assume that we only have input parameters.
   SQLBindParameter(hstmt, i + 1, SQL_PARAM_INPUT, SQL_C_CHAR, DataType, ParamSize,
         DecimalDigits, PtrArray[i], BufferLenArray[i],
         &LenOrIndArray[i]);

   // Prompt the user for the value of the parameter and store it in the memory
   // allocated earlier. For simplicity, this function does not check the value
   // against the information returned by SQLDescribeParam. Instead, the driver does
   // this when the statement is executed.
   strcpy((char*)PtrArray[i], "AAAAAAA");
   BufferLenArray[i] = 7;
   }
}