hi,

i got difficulties inserting a NULL-value into my table:
to tell ODBC, that i want to insert a NULL-value, i use a variable (SQLINTEGER) with a value of SQL_NULL_DATA as last argument to SQLBindParameter:

buffer = new char[255];
strcpy(buffer,"");
SQLINTEGER nInd = SQL_NO_DATA;
SQLPrepare(myHandle,"INSERT INTO TEST (col1) VALUES(?)",SQL_NTS);
SQLBindParameter(myHandle,firstcolumn, SQL_PARAM_INPUT, SQL_C_CHAR,SQL_VARCHAR, 0,0, (void*)buffer, 0, &nInd);
SQLExecute(myHandle);

when i call execute a get an access violation

any idea ?

solution:
1. the length values have to be at least 1 (don't ask me why) otherwise you get an adequate error message.
2. nInd has to be a pointer to SQLINTEGER at least SQLINTEGER[8];

why ? i don't know.

SQLINTEGER nInd[8];
*(SQLINTEGER*)nInd = SQL_NULL_DATA;
SQLBindParameter(myHandle,firstcolumn, SQL_PARAM_INPUT, SQL_C_CHAR,SQL_VARCHAR, 1,0, (void*)buffer, 1, nInd);

i red at least 20 documentations about SQLBindParameter and didn't find a solution. try and error led to the solution - thanks to Bill - the documentations of microsoft give more confusion than help.